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Polyphenolic Chemistry of Tea and Coffee: A Century of Progress
Abstract
Tea and coffee, the most popular beverages in the world, have been consumed for thousands of years for their alluring flavors and health benefits. Polyphenols, particularly flavonoids and phenolic acids, are of great abundance in tea and coffee and contribute a lot to their flavor and health properties. This paper reviews the polyphenol chemistry of tea and coffee, specifically their stability, and scavenging ability of reactive oxygen species (ROS) and reactive carbonyl species (RCS). During the manufacturing and brewing process, green tea and black tea polyphenols undergo epimerization and oxidation, respectively. Meanwhile, the lactonization and the polymerization of chlorogenic acid are the major causes for the degradation of polyphenols in coffee. Tea catechins, besides having antioxidant properties, have the novel characteristic of trapping reactive carbonyl species. The A ring of the catechins is the binding site for RCS trapping, whereas the B ring is the preferred site for antioxidation.
... Subsequently, dry ashing was carried out at a temperature of 525 °C for a time of 4 h. Afterward, the crucible was cooled down and reweighed, with the result expressed as a percent of total ash [54]. ...
... Afterward, the mixture was strained through ashless filter paper and meticulously cleansed with hot water. Following this, the filter paper with the residue was placed back into the crucible, ignited in a muffle furnace, cooled, and reweighed, and the percentage of acid-insoluble ash was calculated [54]. ...
The central goal of this investigation is to optimize static brewing using response surface methodology for the preparation of static brew ready-to-drink Kangra orthodox green tea, while enhancing flavour and quality while incorporating selected sweeteners to satisfy consumer preferences and market requirements. In this study, the concentration of tea leaves (0.95–1%) and steeping time (7–16 h) were determined to be independent variables. The analysis of the statistical data exposed a significant consequence of extraction parameters on all responses. In static brewing, the optimal conditions were 1% w/w orthodox green tea leaves in 4 °C water, steeped for 14.40 h to maximize total phenolic content, antioxidants activity, a*, b* colour value and overall acceptability and to minimize pH, cream, tannins, caffeine and colour value L* of static brewing green tea. The predicted total phenolic content is 248.40 µL GAE/mL, antioxidants activity 92.73 mM TE/mL, a* − 4.17, b* 7.18 colour value and overall acceptability 8.33 and to minimize pH 4.69, cream 1.98%, tannins 19.32 µg TAE/mL, caffeine 33,180 mg/L and L* colour value 42.24 was under optimum static brewing extraction conditions. A balanced taste is achieved in the Kangra Orthodox ready-to-drink tea by combining sugar, honey, and xylitol, because these sweeteners all have varying nutritional and sensory properties. Sweetening agents (8–13° bx) were used to enhance the palatability of the ready-to-drink tea. Optimization of different sweeteners in static brew ready-to-drink Kangra orthodox tea based on sensory rating 10° bx in honey and sugar and xylitol (12° bx) based tea received the highest sensory rating. An innovative aspect of this study is the use of cold static brewing to produce ready-to-drink Kangra orthodox green tea at low temperatures (4 °C), which has demonstrated higher antioxidant activity and sensory appeal than traditional hot tea brewing methods.
... Many bioactive substances in tea, including polyphenols, polysaccharides, vitamins, amino acids, and others with therapeutic benefits, may be used as food additives for creating nutraceuticals (Y. Wang & Ho, 2009). There is an excellent chance that tea's bioactive components will be exploited as food additives that have medical or health benefits for illness prevention and treatment, opening the door for the creation of nutraceuticals (K. ...
Catechins, natural chemicals found in plants, have garnered attention for their therapeutic potential, including preventing atherosclerosis, modulating angiogenesis, mitigating cerebral ischemia, and providing organ-specific protection. Found in dietary sources like green and black tea, catechins are readily absorbed and retain their bioavailability, making them valuable additions to diets. However, despite their promise, catechins face challenges with bioavailability due to factors like oxidative degradation, gastrointestinal instability, and low permeability. Innovative strategies such as hydroxyl group protection and novel delivery systems aim to overcome these obstacles, turning catechins into potent medicinal compounds for drug development. Chemical evidence supports catechins' bioactivity, with studies elucidating their molecular mechanisms and pharmacological effects in vivo and in vitro. Understanding these processes sheds light on how catechins interact with biological systems and exert therapeutic effects. In conclusion, catechins offer diverse health benefits, but addressing their bioavailability issues requires creative solutions. Incorporating catechins into food and nutraceuticals underscores their importance not only as therapeutics but also for overall well-being.
... Caffeine content was reduced from 194.57 ± 6.51 and 103.91 ± 1.62 µg/mL to 176.00 ± 1.70 and 81.04 ± 7.27 µg/mL in BK and CK, respectively, indicating that CK contains much lower caffeine compared with BK. The isomeric transformation of chlorogenic acid isomers and catechin isomers may contribute to the changes in different chlorogenic acids and catechins (Wang & Ho, 2009). The decreased caffeine in both kombucha may be attributed to the effect of yeast. ...
The utilization of coffee leaves in kombucha production has intrigued researchers; however, the lack of understanding regarding the characteristics of coffee leaf kombucha (CK) and its differentiation from black tea kombucha (BK) has impeded its application in the beverage industry. Therefore, this study aimed to characterize and compare the physiochemical properties, phytochemical compositions, antioxidant activity, and α‐glucosidase inhibitory ability of kombucha prepared from the leaves of Coffea arabica (CK) and black tea (Camellia sinensis, BK) and their extracts (CT and BT). After fermentation, pH and the contents of total sugars, reducing sugars, and free amino acids of BK and CK were decreased, whereas the levels of total acids and organic acids, such as gluconic, lactic, and acetic acid were increased. Notably, the concentration of vitamin C in CK was 48.9% higher than that in BK. HPLC analysis exhibited that 5‐caffeoylquinic acid in CT was significantly decreased by 48.0% in CK, whereas the levels of 3‐caffeoylquinic acid and 4‐caffeoylquinic acid were significantly increased after fermentation. The content of caffeine was significantly (p < 0.05) reduced by 9.5% and 22.0% in BK and CK, respectively, whereas the theobromine level was significantly increased in CK. Notably, CK has superior total phenolic and flavonoid contents and antioxidant activity than BK, whereas BK possesses higher α‐glucosidase inhibitory capacity. Electronic nose analysis demonstrated that sulfur‐containing organics were the main volatiles in both kombuchas, and fermentation significantly increased their levels. Our study indicates that coffee leaves are a promising resource for preparing kombucha.
Practical Application
This article investigates the differences in physicochemical properties, bioactive constituents, antioxidant activity, and α‐glucosidase inhibitory activity of kombucha preparation from black tea and coffee leaves. We have found that after fermentation BK had brighter soup color and higher α‐glucosidase inhibitory capacity, whereas CK had higher levels of total phenols, flavonoids, vitamin C, and antioxidants and lower contents of sugars. This study provides valuable information for the preparation of CK with high‐quality attributes and antioxidant activity.
... Chlorogenic acid, [3-(3, 4-dihydroxyphenyl) prop-2enoyl] oxy-1, 4, 5-trihydroxycyclohexane-1-carboxylic acid, is a polyphenolic compound abundantly present in human diet (Clifford 2000;Wang and Ho 2009). Herbs such as Malus domestica (Apple), Cynara cardunculus (artichoke), Piper betel (betel), Arctium (burdock), Daucuscarota (carrots), Coffea arabica (coffee beans), Lonicera (honeysuckle), Actinidia deliciosa (kiwi fruit), and Artemisia absinthium (wormwood) contain chlorogenic acid (Santana-Galvez et al. 2017). ...
Chronic wound healing, especially in burns, is a major medical challenge with limited treatments. This study employs computational tools to identify phytomolecules that target multiple pathways involved in wound healing. By utilizing shape analysis, molecular docking, and binding energy calculations, potential compounds are pinpointed,to address the growing problem of chronic wounds. Initially, a set of phytomolecules from the ZINC database of natural molecules was screened to find compounds with shapes similar to well-known wound healing phytomolecules like curcumin, chromogenic acid, gallic acid, and quercetin. The most promising phytomolecules identified through shape similarity were further studied through molecular docking studies on several key targets involved in wound healing, including TNF-α, FGF, and TGF-β. Among the tested phytomolecules, a ligand known as Fluorophenyl(5-(5-chloro-1-(2-fluorophenyl)-2-oxopentyl)-4,5,6,7-tetrahydrothieno[3,2c]pyridine-2-yl acetate) exhibited a strong affinity with favourable binding interactions for TNF-α ( – 7.1 kcal/mole), FGF (-6.9 kcal/mole), and TGF-β (-5.1 kcal/mole). Another compound, 2,4 methoxybenzylidene-(-3)-oxo-2,3-dihydro-1-benzofuran-6-yl-4-methoxybenzoate, demonstrated a strong affinity with low binding energy for TNF-α ( – 6.8 kcal/mole) and FGF ( – 7.0 kcal/mole) targets. Isosakuranetin and Ermanin displayed moderate affinity for both TNF-α and FGF, with the highest affinity observed for the TGF-β target. These findings suggest that these identified phytomolecules hold promise as potential lead compounds for further structural modifications, with the goal of designing new molecules that can target multiple pathways involved in the wound healing process.
... These substances were listed in Table 2 as oxidation products of EC and EGCG. Theaflavin, TF2a, and theadibenzotropolone A have been identified as yellow pigments in tea (Wang & Ho, 2009). However, theaflavic product of dehydrotheasinensin AQ (m/z 1169) and theaflavic product of dehydrotheasinensin A m/z 1187 have not been reported. ...
... [7]. Melanoidins have been studied, not only because of their nutritional value, but also because of their anti-inflammatory and antioxidant capacity [8], as they exert a radical-scavenging activity with beneficial effects on the lipid profile [9,10]. ...
Aged black garlic (ABG) is a functional food with antioxidant and anti-inflammatory properties. Recent studies also report its beneficial metabolic effects in a context of obesity or diabetes, although the mechanisms involved are poorly understood. The aim of this work was to analyze the effects of an ABG extract in the vascular and metabolic alterations induced by a high-fat/sucrose diet in rats. For this purpose, male Sprague–Dawley rats were fed either a standard chow (controls; n = 12) or a high-fat/sucrose diet (HFD; n = 24) for 16 weeks. From week 8 on, half of the HFD rats were treated with a commercial ABG extract concentrated in S-allyl cysteine and melanoidins (ABG10+®; 250 mg/kg daily by gavage; 5 mL/kg). ABG10+®-treated rats showed lower mean caloric intake, body weight, triglycerides, low density lipoprotein cholesterol (LDL-c), insulin and leptin serum concentrations and higher high density lipoprotein cholesterol (HDL-c) and adiponectin serum concentrations than non-treated rats. In the hypothalamus, ABG10+® treatment induced an increase in the gene expression of proopiomelanocortin (POMC) and a decrease in leptin receptor (ObR) mRNA levels. No significant changes were found in visceral adipose tissue except for an overexpression of β3-adrenergic receptor (β3-ADR) in ABG-treated rats. In subcutaneous adipose tissue, ABG10+® treatment decreased adipose weight and downregulated the gene expression of PPAR-γ, LPL, ObR and HSL. In brown adipose tissue, an overexpression of InsR, GLUT-4, UCP-1 and β3-ADR in ABG10+®-treated rats was found, whereas PPAR-γ mRNA levels were significantly decreased. Regarding vascular function, ABG10+® treatment attenuated the obesity-induced vasoconstriction in response to potassium chloride both in presence/absence of perivascular adipose tissue (PVAT). On the contrary, aorta segments from ABG-treated rats showed and improved relaxation in response to acetylcholine only when PVAT was present, with this fact possible being related to the decreased gene expression of proinflammatory cytokines in this tissue. In conclusion, ABG10+® administration partially improves the metabolic and vascular alterations induced by a high-fat/high-sucrose diet in rats through modifications in the gene expression of proteins and neuropeptides involved in inflammation, fat metabolism and food intake regulation. Further studies are required to assess the bioavailability of ABG between rats and humans.
... Chlorogenic acid, [3-(3, 4-dihydroxyphenyl) prop-2enoyl] oxy-1, 4, 5-trihydroxycyclohexane-1-carboxylic acid, is a polyphenolic compound abundantly present in human diet (Clifford 2000;Wang and Ho 2009). Herbs such as Malus domestica (Apple), Cynara cardunculus (artichoke), Piper betel (betel), Arctium (burdock), Daucuscarota (carrots), Coffea arabica (coffee beans), Lonicera (honeysuckle), Actinidia deliciosa (kiwi fruit), and Artemisia absinthium (wormwood) contain chlorogenic acid (Santana-Galvez et al. 2017). ...
Cancer treatment continues to be a major challenge for the medical community mainly due to non-specificity, leading to serious toxic effects. The use of vitamins such as folic acid and biotin are presently being studied through the synthesis of vitamin-drug conjugates as a new approach to improve the affinity of the drug molecules with cancer cells. Current research emphasizes on the design and synthesis of novel phytochemical vitamin conjugates as anticancer agents through in silico studies. Conjugates of quercetin (QC), curcumin (CUR) and berberine (BER) with folic acid (FA) were evaluated through docking experiments using Autodock Vina. Quercetin-folic acid conjugate 1 (QC-FA 1) demonstrated the highest binding affinity (-12.0 kcal/mol) to the human folate receptor (PDB ID: 4LRH) indicating the possibility of rapid uptake leading to internalization within the cells, improving the specificity to cancer tissues. The conjugates were further examined for their pharmacokinetic properties using AdmetSAR and SMARTcyp tools, which implied the incapability of these conjugates to cross the blood brain barrier but with favorable pharmacokinetic and CYP450 po- tential indicating their ability to act as drug-like molecules. Further QC-FA 1 was synthesized and effectively characterized. This conjugate will be further tested for its efficacy in treatment of cancer
... Fluoride and several antioxidants, including polyphenols, methyl xanthine, bromine, caffeine, tannic acid, and other significant chemicals, are all present in white tea [5,6]. One of the elements found in white tea that is most plentiful is manganese, which aids in the digestion of proteins and is essential for the formation of connective and bone tissue [7,8]. Additionally, it has a healthy amount of vitamins, including vitamin C and E [9]. ...
The importance of research to study the effect of some additives on roosters' diet. The current study aim came intending to know the effect of adding different levels of powder white tea and nettle leaves to roosters' broth in some blood and liver tissue biochemical traits.
... rGO complexed with Mn and intercalated with the reacting residual organic matter to form an encapsulated material. Caffeine participates in the whole process as a stabilizer and capping agent[36]. ...
... offee (Coffea Arabica) is a fragment beverage, consumed during the early morning to begin the day and several times throughout the day by a significant portion of the population of the world. After water and tea, coffee is the third most wellknown drink polished off overall (1). Coffee is cultivated mostly in developing countries employing over 26 million people and traded worldwide as raw or processed beans (2). ...
Introduction and Aim: Mangiferin is accompanied by the therapeutic potential for various human ailments. The present study is aimed to develop a validated HPLC method for the quantification of mangiferin in coffee (Coffea arabica) leaves. Materials and Methods: The high-performance liquid chromatography (HPLC) was carried out on Agilent Technologies 1260 LC Infinity Series liquid chromatography system (Agilent, USA) using an isocratic mobile phase of a mixture of methanol and 1% orthophosphoric acid v/v (70:30) at a flow rate 1mL min-1 for 14 min with the controlled temperature at 25°C. The mangiferin content was detected by a UV diode array detector at 258 nm. Results: The linearity of the HPLC system was established in the range of 10-100 ppm mL-1 with a regression coefficient (R2) of 0.99670. The accuracy of the method was assessed by a study performed using 3 different levels, with a 99% average recovery. The limit of detection(LOD) and limit of quantification (LOQ) were 1.3 and 3.9 ppm mL-1. Intraday and interday precision analysis showed the relative standard deviation 0.012342 separately. The content of mangiferin in the coffee leaves was 94 mg/gram (w/w). Conclusion: All necessary factors, such as linearity, accuracy, LOD, LOQ, precision, and % relative standard deviation(RSD), were inside the appropriate limits. The HPLC was validated using all necessary variables with a successful estimation of mangiferin.
... Catechins are in vitro and in vivo strong antioxidants. Green tea has been extensively studied in people, animals and laboratory experiments [7] . Additionally, Catechins and polysaccharides in green tea have been shown to lower blood sugar. ...
... The former requires a longer fermentation time and is a traditional product of the local population with a slightly sweet and mellow taste. The MJGT is a new product that mimics the process of making green tea, which helps retain more of its original nutritional and medicinal components, especially the multifunctional polyphenolic compounds [9][10][11]. However, its activity and corresponding modes of action on aiding the digestive system have not yet been investigated. ...
Mao Jian Tea (MJT) has been generally consumed as a digestive aid for more than a hundred years in the Shanxi province of China. However, determination of its efficacy still remains elusive. This study investigated the effect of Mao Jian Green Tea (MJGT) on gastrointestinal motility. The biphasic effects of the hydro extracts of MJGT on gastric emptying and small intestinal propulsion of rats were identified in vivo; namely, the low (MJGT_L) and medium (MJGT_M) concentrations promoted gastrointestinal motility (p < 0.05), whereas the high concentration (MJGT_H) showed the opposite effect (p < 0.01). The expression levels of the gastric hormones, GAS, MTL and VIP (p < 0.05) were consistent with the gastrointestinal motility variation, with the exception of MTL in MJGT_H group (p > 0.01). Two flavonoids, eriodictyol (0.152 mg/mL) and luteolin (0.034 mg/mL), and the corresponding glycosides eriodictyol-7-O-glucoside (0.637 mg/mL) and luteolin-7-O-glucoside (0.216 mg/mL), dominated the hydro extracts identified by HPLC and UPLC-ESI-MS. These compounds can regulate the muscle strip contractions isolated from the gastrointestinal tissues. Additionally, the different concentrations also influenced the gut microbiota accordingly characterized by 16S rDNA gene sequencing. The MJGT_L boosted several probiotic bacteria, such as Muribaculaceae (1.77-fold), Prevotellaceae (1.85-fold) and Lactobacillaceae (2.47-fold), and suppressed the pathogenic species such as Staphylococcaceae (0.03-fold) that, conversely, was enriched in the MJGT_H group (1.92-fold). Therefore, the biphasic effect indicated that the dosage of the herbal tea should not be overlooked.
... Green tea catechins obtained from the plant Camellia sinensis, commonly known as green tea, are known to possess antioxidative, anti-inflammatory, antitumor, and antiaging properties. The main catechins in green tea are (-)-epicatechin (EC), (-)-epicatechin-3-gallate (ECG), (-)-epigallocatechin (EGC), and (-)-epigallocatechin-3-gallate (EGCG), which have been shown to constitute approximately 30-40% of the water-soluble fraction in green tea [57]. This class of molecules is extensively studied for its antimicrobial activity against a wide variety of microorganisms [58,59]. ...
Urinary tract infections (UTIs) are the second most common type of bacterial infection worldwide. UTIs are gender-specific diseases, with a higher incidence in women. This type of infection could occur in the upper part of the urogenital tract, leading to pyelonephritis and kidney infections, or in the lower part of the urinary tract, leading to less serious pathologies, mainly cystitis and urethritis. The most common etiological agent is uropathogenic E. coli (UPEC), followed by Pseudomonas aeruginosa and Proteus mirabilis. Conventional therapeutic treatment involves the use of antimicrobial agents, but due to the dramatic increase in antimicrobial resistance (AMR), this strategy has partially lost its therapeutic efficacy. For this reason, the search for natural alternatives for UTI treatment represents a current research topic. Therefore, this review summarized the results of in vitro and animal-or human-based in vivo studies aimed to assess the potential therapeutic anti-UTI effects of natural polyphenol-based nutraceuticals and foods. In particular, the main in vitro studies were reported, describing the principal molecular therapeutic targets and the mechanism of action of the different polyphenols studied. Furthermore, the results of the most relevant clinical trials for the treatment of urinary tract health were described. Future research is needed to confirm and validate the potential of polyphenols in the clinical prophylaxis of UTIs.
... C. sinensis has been used for tea beverage since 3000 B.C. consisting of the leaf and bud of the plant Camellia sinensis [11]. Flavonoid and caffeine are the most abundant type of phenolic compound and alkaloid found in tea respectively [7,12]. Phenolic compounds are considered the most important constituent of tea since it is the largest component and act as bioactive ingredient that enhances the therapeutic action of tea [7,10]. ...
... Chlorogenic acid is one of the amplest polyphenolic compounds in our diet. [72] Chlorogenic acid is a scavenger of free radicals, inhibiting DNA damage and also protecting against carcinogenesis. Chlorogenic acid activates the immune system by proliferation of cytotoxic T-lymphocytes, macrophages, natural killer cells and inhibits matrix MMPs. ...
... By contrast, during black tea manufacturing, the leaves are rolled and crushed to increase the affinity of polyphenol oxidase enzymes for oxygen and to initiate the fermentation process. Oolong tea has a similar fermentation process, but with a lower oxidation degree (Wang & Ho, 2009). During fermentation, monomeric catechins in tea leaves are oxidised to form dimers such as theaflavins, theasinensins, oolongtheasins and other polymers. ...
Three kinds of tea extracts (green tea extract, black tea extract and oolong tea extract) were incorporated into a dry yellow alkaline noodle (YAN) at a concentration of 0.5%–2.0% to investigate their effects on starch gelatinisation, gluten aggregation and noodle quality characteristics. Due to the starch–polyphenol interaction, the temperature and enthalpy required for starch gelatinisation were decreased by 0.90–1.10 °C and 2.85–3.31 J/g, respectively, when 2.0% tea extract was added compared with the control. Furthermore, the dry noodles showed lower starch pasting viscosities (reduced by 28.35%–55.20%) and increased resistance to breakdown and retrogradation. Through the hydrogen bonding between gliadins and tea polyphenols, the conformation of gluten was modified (15.41%–24.62% and 15.19%–22.95% increases in α‐helix and β‐sheet contents, respectively) and its structure was strengthened. The combined effect of tea extracts on starch gelatinisation and gluten formation behaviour resulted in the restricted water permeability and mobility in the structure of cooked noodles, which was associated with increased hardness (13.15–16.34 N), cohesiveness (0.63–0.69), chewiness (7.47–10.88) and resilience (0.34–0.42). It also decreased the absolute adhesiveness (0.11–0.13 N.sec) of cooked YANs. In the alkaline noodle system, three kinds of tea extracts exhibited similar effects on the quality characteristics of YAN. The results suggest that tea extracts are capable of improving YAN texture.
... Green tea leaves have a crude protein content that ranges from 18.15 to 22.9% and metabolizable energy between 11.3 and 14.6 MJ/kg [70]. The leaves are rich in vitamins (A, C, E, K, and B complex), lipids (linolenic and linoleic acids), pigments (carotenoids and chlorophyll), and minerals [71]. Green tea contains beneficial compounds that have stress-reducing functions and antioxidant activities with neurological effects and anti-inflammatory properties [72]. ...
The use of antibiotic growth promoters (AGP) in poultry production not only promotes the emergence of pathogenic multi-drug resistant bacteria, but it also compromises product quality, threatens animal and human health, and pollutes the environment. However, the complete withdrawal of AGP without alternatives could result in uncontrollable disease outbreaks that would jeopardize large-scale poultry intensification. Thus, the use of phytogenic products as potential alternatives to in-feed AGP has attracted worldwide research interest. These phytogenic products contain numerous biologically active substances with antioxidant and antimicrobial activities that can enhance poultry health, growth performance, and meat quality characteristics. In addition, the incorporation of phytogenic products as feed additives in poultry diets could result in the production of high-quality, drug-free, and organic poultry products that are safe for human consumption. Thus, this review examines the current evidence on the antioxidant and antimicrobial properties of a selection of phytogenic products, their effects on nutrient utilization, and physiological and meat quality parameters in poultry. The paper also reviews the factors that could limit the utilization of phytogenic products in poultry nutrition and proposes solutions that can deliver efficient and sustainable poultry production systems for global food and nutrition security.
... Green tea leaves have a crude protein content that ranges from 18.15 to 22.9% and metabolizable energy between 11.3 and 14.6 MJ/kg [70]. The leaves are rich in vitamins (A, C, E, K, and B complex), lipids (linolenic and linoleic acids), pigments (carotenoids and chlorophyll), and minerals [71]. Green tea contains beneficial compounds that have stress-reducing functions and antioxidant activities with neurological effects and anti-inflammatory properties [72]. ...
The use of antibiotic growth promoters (AGP) in poultry production not only promotes the emergence of pathogenic multi-drug resistant bacteria, but it also compromises product quality, threatens animal and human health, and pollutes the environment. However, the complete withdrawal of AGP without alternatives could result in uncontrollable disease outbreaks that would jeopardize large-scale poultry intensification. Thus, the use of phytogenic products as potential alternatives to in-feed AGP has attracted worldwide research interest. These phytogenic products contain numerous biologically active substances with antioxidant and antimicrobial activities that can enhance poultry health, growth performance, and meat quality characteristics. In addition, the incorporation of phytogenic products as feed additives in poultry diets could result in the production of high-quality, drug-free, and organic poultry products that are safe for human consumption. Thus, this review examines the current evidence on the antioxidant and antimicrobial properties of a selection of phytogenic products, their effects on nutrient utilization, and physiological and meat quality parameters in poultry. The paper also reviews the factors that could limit the utilization of phytogenic products in poultry nutrition and proposes solutions that can deliver efficient and sustainable poultry production systems for global food and nutrition security.
... In carrots, for example, boiling results in significant losses of total phenolic compounds (49%), mainly of phenolic acids, except for p-coumaric acid (Mazzeo et al., 2011). Decreases in phenolic compounds may be due to isomerization processes caused by high temperature, as described in green tea by Wang and Ho (2009). These authors found a decrease in epicatechin due to isomerization (alteration of carbon 2) and an increase in catechin after thermal processing. ...
This chapter reviews the range of phenolic compounds in fruits and vegetables. It assesses the effects on phenolic content of factors such as cultivar, stage of growth (ripening), cultivation practices such as use of bio-effectors, and post-harvest stages such as mechanical and thermal processing as well as storage. It also looks at using fruit and vegetable by-products such as peel to produce value-added nutraceutical compounds.
... Compound 64 at m/z 289 produced a main fragment ion at m/z 245 after removing CO 2 from the precursor ion and was identified as epicatechin (C 15 H 14 O 6 ). Catechins are an important class of flavonoids present in coffee and tea[44,45]. ...
Coffee is the most widely used beverage globally and contains many bioactive compounds, including phenolic compounds, alkaloids, triterpenes, organic acids, amino acids, hormones, and fatty acids. The main objective of this study was the comparative profiling of Australian, Colombian, Ethiopian, and Peruvian C. arabica using LC-ESI-QTOF-MS/MS. In this study, we tentatively identified 136 bioactive metabolites, including five (05) organic acids, six (06) alkaloids, three (03) amino acids (l-phenylalanine, l-tyrosine, and l-pyroglutamic acid), two (02) hormones (melatonin and serotonin), two fatty acids, one (01) furopyrans (goniothalenol), one (01) carotenoid (crocetin), three (03) terpenoids, thirty-eight (38) phenolic acids, forty-one (41) flavonoids, five (05) stilbenes, three (03) lignans and twenty-three (23) other polyphenols in C. arabica. The highest TPC value (17.74 ± 0.32 mg GAE/g) was measured in Colombian coffee while the lowest TPC value (10.24 ± 0.73 mg GAE/g) was in Peruvian coffee. Colombian coffee has a higher antioxidant potential than other studied coffee samples. A total of nineteen phenolic metabolites were mapped through LC-MS/MS. Quinic acid derivatives were quantified in higher concentrations than other metabolites. Furthermore, molecular docking predicted that chlorogenic acid is a main bioactive compound that contributes to anti-Alzheimer and anti-diabetic activities of C. arabica. The obtained results indicate that C. arabica contains a vast number of bioactive compounds which have potential health benefits. Furthermore, research could be conducted to validate the effect of these metabolites on the flavor profile of coffee beverages.
... Green tea is made from fresh leaves of C. sinensis processed to prevent oxidation of its polyphenolic compounds [87,88]. Catechins are the main polyphenols present in green tea, representing about 30% to 42% of the water-soluble solids of this tea [89]. Its content is influenced by several factors, such as geographic location, growing conditions, and the degree of fermentation [83]. ...
Over the past few decades, interest in medicinal plants and phytochemicals for the treatment of skin disorders, including acne vulgaris, has progressively increased. Acne vulgaris is a chronic in ammatory disease of the pilosebaceous unit, which mainly occurs in adolescents and young adults. e treatment focuses on the four main factors involved in its pathogenesis: increased sebum production, hyperkeratinization, overgrowth of Cutibacterium acnes, and in ammation. e treatment includes topical retinoids, benzoyl peroxide, antibiotics, and oral isotretinoin. In this regard, the use of herbal medicine as a complementary and alternative medicine is a promising strategy. e main objective of this study was to systematically evaluate the e cacy and safety of medicinal plants and phytochemicals in the treatment of acne vulgaris. ree scienti c databases (PubMed, Web of Science, and Scopus) were searched from inception to January 2021. Clinical trials comparing herbal therapies with placebo or other medicines for the treatment of acne vulgaris were included and analyzed. Outcome measures of interest comprised acne lesions (in-ammatory and nonin ammatory), sebum production, acne severity, and quality of life. e risk of bias in the included randomized controlled trials (RCTs) was assessed using the Cochrane risk-of-bias tool. A total of 34 clinical trials involving 1753 participants met the inclusion criteria for this systematic review. Most trials showed that herbal medicine signi cantly reduces in ammatory and nonin ammatory acne lesions and has a relevant e ect on acne severity. Some medicinal plants revealed equal or higher e cacy to standard treatments. No signi cant di erence between groups in sebum production and quality of life was observed and no severe adverse events were reported. is systematic review provides evidence that medicinal plants and phytochemicals are promising treatments for mild to moderate acne vulgaris. However, more quality of evidence and standardized methodologies are needed to support their e ectiveness and safety claims.
... There are two groups of interesting polyphenolic compounds present in tea: catechins and flavonols. (-)-epigallocatechin gallate (EGCG) is generally regarded as the major catechins in tea, other ubiquitous catechins are (-)-epicatechin (EC), (-)-Epigallocatechin (EGC), (-)-epicatechin-3-O-gallate (ECG) (Wang & Ho, 2009). However, the fermentation process of dark tea converts simple catechins into complex theaflavins or thearubigins, which is responsible for its dark brown color and astringent properties, but they also possess strong antioxidant activity (Kayisoglu & Coskun, 2021). ...
... Green tea contains a class of polyphenolic flavonoid compounds known as catechins which contribute to the health-promoting effects ( [3]. Epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC), and epigallocatechin gallate (EGCG) are the four main catechins in green tea [4][5][6][7]. ...
Green tea powder (GTP) is rich in polyphenolic compounds, most particularly catechins. The effects of partial replacement of flour with GTP (10, 20, and 30%) on physicochemical properties, glycemic potential, and sensory attributes were investigated. Results showed a significant reduction in the moisture content, volume, and porosity of sample cakes with the increase in the GTP levels (P≤0.05). The utilization of GTP led to a harder texture and also darker color of sponge cake. The study showed that sponge cakes with good sensory attributes can be produced by the replacement of flour with 10% of GTP. Moreover, the glycemic potential and free radical scavenging activity of sample cakes improved as the GTP replacement increased (P≤0.05). GTP at 10% replacement level is recommended as it is very effective in improving the antioxidant properties, sensory attributes, and also glycemic potential.
... There are two most popular types of tea, green tea, and black tea, classified according to foliar fermentation. Green tea does not undergo fermentation, while black tea is fully fermented; however, both are rich in alkaloids and phenolic compounds, mainly flavonoids and acids, which have a broad spectrum of biological properties ( Wang & Ho, 2009 ). ...
The antimicrobial and antileukemic effect of a purified fraction of flavonoids from the leaves of Camellia sinensis was evaluated. An extraction yield of 9.77 mg.g-1 total flavonoids was recovered through a pressurized liquid extraction associated with solid-phase extraction. This fraction was tested against pathogenic microorganisms (Staphylococcus, Salmonella, and Enterococcus), considering the minimum inhibitory concentration. In addition, the human monocyte cell line THP-1, derived from a patient with acute monocytic leukemia, was used for the antitumor assay. The results show that the flavonoid-rich fraction obtained by coupling a Pressurized Liquids Extraction in-line with a Solid Phase Extraction (PLE-SPE) has a high antimicrobial effect and resulted in cell cycle blockage G0 / G1, increased DNA fragmentation, and altered leukemic cell morphology. These results suggest that a flavonoid-rich fraction obtained from Camellia sinensis can be applied as potential adjuvants in chemotherapy treatment to mitigate the side effects caused by chemotherapy or even as a supplement to cancer therapy.
... Coffee consumption is associated with various long-term health benefits, in particular on age-associated diseases whose onset is related to chronic inflammation, such as cardiovascular diseases (Rodríguez-Artalejo and López-García 2018), chronic liver diseases (Ruhl and Everhart 2005), diabetes (Kempf et al., 2010), and cancer (Pauwels and Volterrani 2021). The antiinflammatory effects of coffee were extensively reviewed (Wang and Ho 2009). Coffee contains a number of compounds including caffeine, diterpenes, such as kahweol, and several polyphenols, such as chlorogenic acids (CGAs), which are a large family of (-)-quinic acid esters of hydroxycinnamic acids (mainly caffeic acid, ferulic acid and p-coumaric acid), the most abundant being 5-O-caffeoylquinic acid (5-CQA) (Perrone et al., 2008;Clifford et al., 2017). ...
The anti-inflammatory activity of coffee extracts is widely recognized and supported by experimental evidence, in both in vitro and in vivo settings, mainly murine models. Here, we investigated the immunomodulatory properties of coffee extracts from green (GCE) and medium-roasted (RCE) Coffea canephora beans in human macrophages. The biological effect of GCE and RCE was characterized in LPS-stimulated THP-1-derived human macrophages (TDM) as a model of inflammation. Results showed decreased amounts of TNF-α, IL-6 and IL-1β and a strong dose-dependent inhibition of interferon-β (IFN-β) release. Molecular mechanism of IFN-β inhibition was further investigated by immunofluorescence confocal microscopy analysis that showed a diminished nuclear translocation of p-IRF-3, the main transcription factor responsible for IFN-β synthesis. The inhibition of IFN-β release by RCE and GCE was also confirmed in human primary CD14 ⁺ monocytes-derived macrophages (MDM). The main component of coffee extracts, 5- O -caffeoylquinic acid (5-CQA) also inhibited IFN-β production, through a mechanism occurring downstream to TLR4. Inhibition of IFN-β release by coffee extracts parallels with the activity of their main phytochemical component, 5-CQA, thus suggesting that this compound is the main responsible for the immunomodulatory effect observed. The application of 5-CQA and coffee derived-phytoextracts to target interferonopathies and inflammation-related diseases could open new pharmacological and nutritional perspectives.
... Abdo et al. [47] reported that GT leaves can provide between 11.3 and 14.6 MJ/kg metabolisable energy (Table 1), which is adequate for growing and laying quail (11.7 MJ/kg and 10.7 MJ/kg, respectively) [52]. The leaves also contain high concentrations of minerals and trace elements, vitamins (A, C, E, K, and B complex), lipids (α-linolenic and linoleic acids), and pigments (carotenoids and chlorophyll) [53], which could be the reason why most research focused on its potential as a source of dietary nutrients. Moreover, the leaves also possess complex carbohydrates, such as pectins, cellulose, hemicellulose, and lignin [54], which limit their utilisation in poultry, especially at higher dietary levels [55]. ...
The overuse and misuse of antibiotics in poultry feeds increase the total cost of production and compromise the quality of poultry products, which poses a serious threat to human health. Globally, health-conscious poultry consumers have long called for the alternate use of natural additives to mitigate the development and spread of multidrug resistant pathogens. Phytogenic plants, such as green tea (Camellia sinensis) products, contain putative nutraceuticals with antibiotic properties that can be used as alternatives to therapeutic, metaphylactic, prophylactic, and growth�promoting antibiotics. However, there are limited studies in the literature that have evaluated the potential of green tea (GT) products when used as replacements to in-feed antibiotics, with most studies focusing on their potential as sources of dietary nutrients in poultry feeds. Thus, this review paper discusses the potential of GT products to replace various antibiotics in poultry diets while presenting GT bioactive substances that can improve the growth performance, carcass and meat quality traits, and health status of the birds. We postulate that the utilisation of GT products in place of antibiotics could deliver sustainable, organic poultry production systems that would contribute significantly to global food and nutrition security.
... Abdo et al. [47] reported that GT leaves can provide between 11.3 and 14.6 MJ/kg metabolisable energy (Table 1), which is adequate for growing and laying quail (11.7 MJ/kg and 10.7 MJ/kg, respectively) [52]. The leaves also contain high concentrations of minerals and trace elements, vitamins (A, C, E, K, and B complex), lipids (α-linolenic and linoleic acids), and pigments (carotenoids and chlorophyll) [53], which could be the reason why most research focused on its potential as a source of dietary nutrients. Moreover, the leaves also possess complex carbohydrates, such as pectins, cellulose, hemicellulose, and lignin [54], which limit their utilisation in poultry, especially at higher dietary levels [55]. ...
The overuse and misuse of antibiotics in poultry feeds increase the total cost of production and compromise the quality of poultry products, which poses a serious threat to human health. Globally, health-conscious poultry consumers have long called for the alternate use of natural additives to mitigate the development and spread of multidrug resistant pathogens. Phytogenic plants, such as green tea (Camellia sinensis) products, contain putative nutraceuticals with antibiotic properties that can be used as alternatives to therapeutic, metaphylactic, prophylactic, and growth-promoting antibiotics. However, there are limited studies in the literature that have evaluated the potential of green tea (GT) products when used as replacements to in-feed antibiotics, with most studies focusing on their potential as sources of dietary nutrients in poultry feeds. Thus, this review paper discusses the potential of GT products to replace various antibiotics in poultry diets while presenting GT bioactive substances that can improve the growth performance, carcass and meat quality traits, and health status of the birds. We postulate that the utilisation of GT products in place of antibiotics could deliver sustainable, organic poultry production systems that would contribute significantly to global food and nutrition security.
Respiratory diseases caused by viruses are a serious global health threat. Although the use of hand sanitizers containing alcohol and synthetic antiseptic agents is recognized as an effective, simple, and low-cost measure to combat viral transmission, they can harm human health and the environment. Thus, this work aimed to study the efficacy of combining Camellia sinensis and Chamomilla recutita extracts in a skin- and eco-friendly leave-on hand sanitizer to prevent the spread of respiratory viruses. An oil-in-water emulsion containing C. recutita oily extract (5.0%), C. recutita glycolic extract (0.2%) and C. sinensis glycolic extract (5.0%) showed virucidal activity against HAdV-2 (respiratory virus) and two surrogate viruses of SARS-CoV-2 (HSV-1 and MVH-3), showing great potential to prevent the spread of respiratory viruses. These natural extracts combined are also promising to combat a broad spectrum of other viruses, in the form of antiseptic mouthwashes or throat sprays, surface disinfectants, and veterinary products, among others. Complementally, the developed hand sanitizer demonstrated efficacy against bacteria and fungus.
Employing natural abundant bio-materials in fabrication of electronic devices is promising for the development of an eco-friendly community. Herein, we report that tea polyphenols (TPs) can be used as small...
Natural products can be used as therapeutic agents for several types of diseases, including those that affect the oral cavity. Among these products, antioxidants stand out, which are substances capable of delaying or neutralizing substrates generated from chemical and biochemical processes, in addition to modulating inflammatory and bacterial processes commonly present in oral diseases such as caries and periodontitis. Caries is the most common disease of the oral cavity, in which it develops from dental biofilm composed of different microorganisms adhered to the tooth surface. Periodontitis is a chronic inflammatory disease linked to the destruction of tooth support structures as a result of the accumulation of bacterial biofilm. Several studies demonstrate that grape seed extract, green tea, vitamin C, lycopene, and resveratrol have important antioxidant, antimicrobial, and anti-inflammatory properties capable of reducing the production of proinflammatory cytokines, thus preventing the appearance of these diseases or their development. The purpose of this chapter is to present the antioxidant effects of natural products on diseases of the oral cavity, caries and periodontitis.KeywordsNatural productsAntioxidantsTherapeuticOral cavityCariesPeriodontitisGreen teaVitamin CLycopeneResveratrol
The synthesis and characterization of silver nanoparticles (AgNPs) was planned for the first time by applying microwave method from 2% (w/v) aqueous solutions of green tea extract obtained by microwave extraction from the Eastern Black Sea region of Turkey and catechin extract separated by SFE extraction in this study.100 mL of AgNO 3 aqueous solution varying between 0.5 mM-10 mM were added to the green tea and catechin extract (2 w/v) aqueous solutions in different volume (0.5mL-4mL) derived in consequence of the extractions and Ag nanoparticles were produced in a household microwave at 90 W power for 1–60 minutes in the presence and absence of PEG. Uv-Vis, FTIR, TEM, XRD and Zetasizer were applied in the characterization of Ag nanoparticles synthesized using green chemistry principles. In this method, AgNPs were successfully produced in 0.5 mL extract volume using 1 mM AgNO 3 aqueous solution. Each method was repeated three times. As a result, it was concluded that AgNP can be produced easily, economically and quickly by using green tea and catechin extracts in this study.
Background
For decades, evidence from observational studies and randomized controlled trials has converged to suggest associations of dietary components, foods, and dietary patterns with dementia. With population aging and a projected exponential expansion of people living with dementia, formulating nutritional strategies for dementia prevention has become a research hotspot.
Objective
This review aimed to summarize available data on the roles of specific dietary components, food groups, and dietary patterns in dementia prevention among the elderly.
Method
Database search was carried out using PubMed, the Cochrane Library, EMBASE, and Medline.
Results
Polyphenols, folate, vitamin D, omega-3 fatty acids, and β-carotene might decrease the risk of dementia. Consumption of green leafy vegetables, green tea, fish, and fruits is recommended. However, saturated fat, a diet rich in both dietary copper and saturated fat, aluminum from drinking water, and heavy drinking might increase dementia risk. Healthy dietary patterns, especially the Mediterranean diet, were proven to bring more cognitive benefits than single dietary components.
Conclusion
We discussed and summarized the evidence on the roles of dietary components and patterns in dementia prevention among the elderly and found that some factors were closely associated with dementia risk in elderly. This may pave the way for the identification of dietary components and patterns as new therapeutic targets for dementia prevention in the elderly population.
Bu çalışmada Türkiye piyasasından toplanan protein içeriği artırılmış laktozsuz UHT sütlerde bir takım fizikokimyasal analizler ile toplam fenolik madde ve antioksidan aktivite tayinleri gerçekleştirilmiştir. Bu çalışmanın amacı; özel beslenme gruplarına (laktoz intoleransına sahip bireyler/aktif spor yapan bireyler) hitap eden ve tüketimi yaygın olan protein içeriği artırılmış laktozsuz süt ürünlerinin özellikle son dönemlerde oldukça popüler olan ve sağlığa etkileri bilinen antioksidan kavramı üzerinden irdelenmesidir. Genel olarak farklı markalara ait aynı aromayı içeren ürün grupları içerisinde kurumadde değişimi önemli iken (p<0,05), pH değerleri değişimi ise önemsiz bulunmuştur (p>0,05). Ürünlerin fenolik madde ve antioksidan aktivite değerleri incelendiğinde, en yüksek değer (sırasıyla 2546,25 mg GAE/L ve 7,01 mM) protein içeriği artırılmış kahveli laktozsuz süt (9B) örneğinde tespit edilmiştir (p<0,05). Özellikle kahveli ve kakaolu örneklerde toplam fenolik madde ve antioksidan aktivite değerleri açısından kendi içlerindeki değişim önemsiz iken (p>0,05), diğer ürün gruplarından farklılıkları önemli düzeyde bulunmuştur (p<0,05). Ürün grupları arasında toplam fenolik madde ve antioksidan aktivite değerleri açısından değişim önemli düzeyde bulunmuştur (p<0,05).
Albino tea has been receiving growing attention on the tea market due to its attractive appearance and fresh taste, mainly caused by high amino acid contents. Here, variations in the contents of five free amino acids in relation to pigment contents and tree age in two hybrid populations'Longjin 43'(♀) × 'Baijiguan'(♂) and 'Longjin 43'(♀) ×'Huangjinya'(♂) with 334 first filial generation individuals including chlorophyll-deficient and normal tea plants were investigated. The data showed that the contents of main amino acids in all filial generation gradually decreased as plant age increased. Principal component analysis indicated that the amino acid content of individual plant tended to be stable with the growth of plants. Correlation analysis clarified that several main amino acids were significantly negatively correlated with chlorophyll a, chlorophyll b and carotenoid contents. Our results showed that the accumulation of amino acids in tea plant was closely related to leaf color variation and the tree age during growing period.
Ocimum gratissimum is a herbaceous medicinal plant known for its high antioxidant activity. In the present study, we investigated the effect of different tea manufacturing processes in retaining the biochemical properties of O. gratissimum and determined which of the processes yields a high-quality tea. We determined the color tone, total polyphenol content (TPC), odor, 2-diphenyl-1-picrylhydrazyl (DPPH) values, and hydrophilic oxygen radical absorbance capacity (H-ORAC) of treated samples. Steaming time affected the color tone, TPC, DPPH value, chicoric acid content, and odor, while the drying temperature and fermentation treatment affected all the parameters. Furthermore, caryophyllene, germacrene-D, and eugenol were identified as the main aroma compounds in O. gratissimum. Our findings indicate that the drying temperature and fermentation treatment are the major factors affecting the biochemical properties and acceptance quality of O. gratissimum tea. Among the different treatments used, machine-drying without steaming treatment was the best on odor. Freeze-drying, which is more costly, was the best on the TPC and antioxidant activities; however, it was found that MD, which is relatively cheap compared to freeze-drying treatment, maintained high TPC, DPPH, H-ORAC values, and chicoric acid content by steaming for 2 minutes before drying.
The present study was conducted to evaluate the immunostimulatory effect of tea leaf extract (Camellia sinensis) on Labeo rohita and its resistance against Aeromonas hydrophila infection. The ethanolic extract of green tea (GTEE) was found to be the most potent as compared to other solvent extract which was used for further study. It was used to evaluate immune-biochemical response of L. rohita fingerlings, fed with tea leaf extract (control- 0.0%, 0.2% (T1), 0.4% (T2), 0.8% (T3) and 1% (T4) of GTEE kg⁻¹ feed). Different biochemical parameters like glucose, ALP, GPT, GOT, and immunological parameters like lysozyme activity, NBT, anti-protease activity, myeloperoxidase activity, plasma protein, and immune relevant genes (IL-10, C3, Lysozyme G type and iNOS) expressions were carried out. The immunological parameters such as lysozyme activity, NBT and myeloperoxidase activity showed significantly high value once fed with GTEE incorporated diets. Significant up-regulation of immune genes indicated the enhancement of immune response at molecular level. The biochemical parameters were found to be significantly decreasing, indicating that the extract had hepato-protective effect and can help to overcome stress. The fish, fed with GTEE incorporated diets, showed resistance against A. hydrophila when compared with the control group. 0.2% GTEE showed the highest post-challenged survival (76.67%). From the present study, it is concluded that GTEE @ 0.2% can be used as potent immunostimulant as a sustainable alternative prophylactic and therapeutic agent in aquaculture.
With the development of economy, beverage has gradually become an indispensable and important role in People’s Daily life. The use of enzymes in ready-to-drink (RTD) tea and coffee products has contributed in increasing the yield and production of various types of nutrition additions. The enzyme treatments have also been tried in three stages of tea processing, for instance, enzymatic treatment to green tea and conversion to black tea, followed by extraction, and enzymatic clarification of extract. Enzymes are able to remove bitterness of tea or coffee products, extract pigments, among other applications, have also had great prospect in the RTD tea and coffee products industry. The reuse of RTD tea and coffee industrial wastes to produce value-added products could also be achieved by enzyme catalysis, while reducing carbon emissions, energy consumption and environmental pollution, as well as increasing production. The application of enzyme technology in the value addition of RTD tea and coffee products was discussed.
Tea catechins, an important class of polyphenols, have been shown to have wide spectrum of antitumor activity believed to be due mainly to their antioxidative effect. In this study, the radical scavenging behavior of catechins on 2,2-diphenyl-1-picrylhydrazyl (DPPH) was studied. Two reaction products of (+)-catechin, and two reaction products of (-)-epicatechin were purified and identified. Their structures were determined on the basis of detailed high-field 1-D and 2-D NMR spectral analysis. Structure elucidation of these products can provide insights into specific mechanisms of antioxidant reactions. A possible mechanism of the formation of reaction products is suggested.
Collagen crosslinking during aging in part results from Maillard reaction endproducts of glucose and oxoaldehydes. Because of the tight link between oxidative and carbonyl stress, we hypothesized that natural antioxidants and "nutriceuticals" could block collagen aging in C57BL/6 mice. Six groups of young and adult mice received vitamin C, vitamin E, vitamin C&E, blueberry, green tea extract (GTE), or no treatment for a period of 14 weeks. Body weights and collagen glycation were unaltered by the treatment. However, GTE or vitamin C&E combined blocked tendon crosslinking at 10 months of age (p < 0.05, adult group). GTE also blocked fluorescent products at 385 and 440 nm (p = 0.052 and < 0.05, respectively) and tended to decrease skin pentosidine levels. These results suggest that green tea is able to delay collagen aging by an antioxidant mechanism that is in part duplicated by the combination of vitamin C and E.
Of all plant constituents, coffee has one of the highest concentrations of chlorogenic acids. When roasting coffee, some of these are transformed into chlorogenic acid lactones (CGL). We have studied the formation of CGL during the roasting of coffee beans in Coffea arabica cv. Bourbon; C. arabicacv. Longberry; and C. canephora cv. Robusta. Individual CGL levels were determined by comparison of HPLC peaks with those of synthetic CGL standards. Seven CGL were identified: 3-caffeoylquinic-1,5-lactone (3-CQL), 4- caffeoylquinic-1,5-lactone (4-CQL), 3-coumaroylquinic-1,5-lactone (3-pCoQL), 4-coumaroylquinic-1,5-lactone (4-pCoQL), 3-feruloylquinic-1,5-lactone (3-FQL), 4-feruloylquinic-1,5-lactone (4-FQL), and 3,4-dicaffeoylquinic-1,5-lactone (3,4-diCQL). 3-CQL was the most abundant lactone in C. arabica and C. canephora, reaching peak values of 230 +/- 9 and 254 +/- 4 mg/100 g (dry weight), respectively, at light medium roast ( approximately 14% weight loss). 4-CQL was the second most abundant lactone (116 +/- 3 and 139 +/- 2 mg/100 g, respectively. The maximum amount of CGL represents approximately 30% of the available precursors. The relative levels of 3-CQL and 4-CQL in roasted coffee were reverse to those of their precursors in green coffee. This suggests that roasting causes isomerization of chlorogenic acids prior to the formation of lactones and that the levels of lactones in roasted coffee do not reflect the levels of precursors in green coffee.
This paper is a comprehensive review of the effects of bioactive polyphenolic compounds commonly found in many fruits and vegetables on cancer. These include the pheniolic acids, anthocyanins, catechins, stilbenes and several other flavonoids. We have attempted to compile information from most of the major studies in this area into one source. The review encompasses the occurrence and bioavailability of the polyphenolics, the in vitro and in vivo evidence for their effects on cancer, both positive and negative, and the various mechanisms by which the chemicals may exert their effects. Although most of the work done to date indicates a chemopreventative activity of these compounds, there are some studies that show cancer-inducing or no effects. There are several common mechanisms by which these chemicals exert their effects that could be conducive to additive, synergistic, or antagonistic interactions. These include effects on cellular differentiation, proliferation, and apoptosis, effects on proteins and enzymes that are involved in these processes at a molecular level, and other various effects through altered immune function and chemical metabolism.
A minority of persons at risk develop liver cirrhosis, but knowledge of risk modulators is sparse. Several reports suggest that coffee drinking is associated with lower cirrhosis risk.
We studied 125,580 multiethnic members of a comprehensive prepaid health care plan without known liver disease who supplied baseline data at voluntary health examinations from 1978 to 1985. Subsequently, through 2001, 330 of them were diagnosed with liver cirrhosis. Review of medical records confirmed the diagnosis of cirrhosis and ascertained probable etiology. The association of coffee drinking with cirrhosis was estimated by Cox proportional hazards models with 7 covariates. We also did a cross-sectional analysis of baseline aspartate aminotransferase and alanine aminotransferase levels, studied by logistic regression.
In the cohort study, relative risks of alcoholic cirrhosis (199 subjects) for coffee drinking (vs none) were less than 1 cup per day, 0.7 (95% confidence interval [CI], 0.4-1.1); 1 to 3 cups, 0.6 (95% CI, 0.4-0.8; P<.001); and 4 or more cups, 0.2 (95% CI, 0.1-0.4; P<.001). For 131 subjects with nonalcoholic cirrhosis, relative risks were less than 1 cup, 1.2 (95% CI, 0.6-2.2); 1 to 3 cups, 1.3 (95% CI, 0.8-2.1); and 4 or more cups, 0.7 (95% CI, 0.4-1.3). These relative risks for coffee drinking were consistent in subsets. Tea drinking was unrelated to alcoholic or nonalcoholic cirrhosis. In the cross-sectional analyses, coffee drinking was related to lower prevalence of high aspartate aminotransferase and alanine aminotransferase levels; for example, the odds ratio of 4 or more cups per day (vs none) for a high aspartate aminotransferase level was 0.5 (95% CI, 0.4-0.6; P<.001) and for a high alanine aminotransferase level, 0.6 (95% CI, 0.6-0.7; P<.001), with stronger inverse relations in those who drink large quantities of alcohol.
These data support the hypothesis that there is an ingredient in coffee that protects against cirrhosis, especially alcoholic cirrhosis.
Theaflavins and thearubigins are major pigments of black tea. In the course of studies on the oxidation mechanism of tea polyphenols, a new type of tea pigment, theadibenzotropolone A, together with theaflavin 3-gallate were formed by the reaction of (-)-epicatechin (EC) and (-)-epigallocatechin gallate (EGCG) with horseradish peroxidase in the presence of H2O2. The structure of theadibenzotropolone A was elucidated on the basis of MS and 2D NMR spectroscopic analyses. The observation that galloyl ester groups of theaflavins can be oxidized to form dibenzotropolone skeletons strongly implied that this type of oxidation as an important pathway to extend the molecular size of thearubigins. The existence of this compound in black tea was characterized by LC/ESI-MS/MS. Theadibenzotropolone A is the first theaflavin type trimer of catechins in black tea.
Three novel chalcan-flavan dimers, assamicains A (1), B (2) and C (3), and a new flavan-3-ol (14) and proanthocyanidins (19, 20) have been isolated, together with the known flavan-3-ols (4-13), proanthocyanidins(15-18, 21), theasinensins (22-24) and hydrolyzable tannins (25, 26), from the fresh leaves of Camellia sinensis var. assamica (Camelliaceae), and their structures have been established on the basis of spectroscopic evidence in conjunction with thiolytic degradation and enzymatic hydrolysis.
The structures, relative configurations and precursors of seven pigments isolated from the theaflavin fraction of black tea have been established by synthesis, and by NMR and mass spectrometry. The four principal pigments are the bis-flavan-substituted 1′,2′-dihydroxy-3,4-benzotropolones theaflavin, the corresponding isomeric 3- and 3′-monogallates, and the 3,3′-digallate. Collapsed spin-spin couplings and nuclear Overhauser effects in these and a range of mono-flavan-substituted model compounds are interpreted in terms of steric hindrance to rotation of flavan groups with respect to the benzotropolone ring. As a result of these steric effects, the 3-gallate and 3,3′-digallate exist in rotameric forms which are clearly distinguished in the temperature-dependent CD spectra.
Specimens of cathechins and gallocatechins and their gallate esters, isolated from green tea, have been examined by the method of filter-paper chromatography. Regularities are observed between chromatographic behaviour, molecular rotation and chemical constitution, and these suggest that the l-gallocatechin of tea would be more suitably designated by l-epigallocatechin.RésuméNous avons examiné par la méthode de chromatographie sur papier-filtre des spécimens de catéchines et de gallocatéchines et de leurs esters galliques isolés du th'e vert. Les régularités observées entre le comportement chromatographique, la rotation moléculaire et la constitution chimique suggèrent que la du thé serait désignée de façon plus adéquate par le nom de l-epigallocatechine.ZusammenfassungAus grünem Thee isolierte Proben von Catechin, Gallocatechin und ihren Gallensäureestern wurden unter Anwendung der Filterpapier-Chromatographie untersucht. Zwischen dem chromatographischen Verhalten, der Molekularrotation und der chemischen Konstitution wurden Regelmässigkeiten beobachtet, die darauf hinweisen, dass l-Gallocatechin besser als l-Epigallocatechin bezeichnet werden könnte.
Some of the most exciting research in the last decade has been the discovery of a group of nutrients which have protective effects against cell oxidation. These naturally occurring compounds impart bright colour to fruits and vegetables and act as antioxidants in the body by scavenging harmful free radicals, which are implicated in most degenerative diseases. Epidemiological studies have established a positive correlation between the intake of fruits and vegetables and prevention of diseases like atherosclerosis, cancer, diabetes, arthritis and also ageing. So pronounced has been their effect on ageing that they have been called 'fountains of youth'. Fruits and vegetables have thus had conferred on them the status of 'functional foods', capable of promoting good health and preventing or alleviating diseases. Phenolic flavonoids, lycopene, carotenoids and glucosinolates are among the most thoroughly studied antioxidants. The present review highlights the potential of fruits and vegetables rich in antioxidants, their health benefits and the effect of processing on the bioavailability of these nutrients. The paper also reviews some of the important methods used to determine the antioxidant activity.
An isocratic HPLC procedure was developed for simultaneous determination of six catechins, gallic acid, and three methylxanthines in tea water extract. A baseline separation was achieved on a Cosmosil C18-MS packed column with a solvent mixture of methanol/doubly distilled water/formic acid (19.5:80.2:0.3, v/v/v) as mobile phase. A gradient HPLC procedure was also provided for the separation of these tea components. The contents of catechins, gallic acid, and methylxanthines have been measured in infusions of a range of green tea, oolong tea, and pu-erh tea products sold and consumed in the China, Japan, and Taiwan. When 15 Chinese green tea and 13 Japanese green tea products were analyzed by the HPLC method, the mean levels of the total catechins, (−)-epigallocatechin 3-gallate, (+)-catechin, and caffeine were found to be very similar in these two groups, but other minor catechins such as (−)-epigallocatechin, (−)-epicatechin, and (−)-gallocatechin 3-gallate were found to be higher in Japanese green tea products, whereas (−)-epicatechin 3-gallate, gallic acid, theophylline, and theobromine were found to be higher in Chinese green tea products. Oolong tea products possessed lower levels of catechins, whereas pu-erh tea products contained negligible amounts of these constituents. The new HPLC method is rapid, reliable, and reproducible and should be highly recommended to tea industries for routine analysis of commercial tea samples. Keywords: Catechins; gallic acid; caffeine; theophylline; theobromine; green tea; oolong tea; paochong tea; pu-erh tea; black tea; isocratic HPLC
Hydroxycinnamic acid compounds are an important source of antioxidants due to their ubiquitous occurrence in the plant kingdom and their characteristic activities. In this study, we compared the antioxidative and free radical scavenging activities of caffeic acid (CA), caffeic acid phenethyl ester (CAPE), ferulic acid (FA), ferulic acid phenethyl ester (FAPE), rosmarinic acid (RA), and chlorogenic acid (CHA) with those of α-tocopherol and BHT. In the Rancimat test, the addition of test compounds in lard significantly extended the induction time of lipid oxidation, and the activities in decreasing order were CA α-tocopherol > CAPE RA > CHA BHT > FA FAPE. When the lipid substrate was changed to corn oil, the effectiveness of antioxidants on the induction time was obviously decreased, and the potency order of antioxidants was changed to RA > CA CAPE CHA > α-tocopherol > BHT; FA and FAPE had no significant antioxidative effect in the corn oil system. The 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activity of the test compounds was RA CAPE > CA > CHA > α-tocopherol > FA > FAPE > BHT. The effect on retarding oil-in-water emulsion oxidation was BHT > CA > CAPE > RA > FA > CHA > α-tocopherol > FAPE, and the incubation times to reach an absorbance of 0.4 by the ferric thiocyanate method were 14.4, 11.4, 8.6, 7.3, 6.4, 4.6, 4.2, and 2.8 days, respectively, with the value of the control around 1.3 days. Keywords: Antioxidants; caffeic acid; caffeic acid phenethyl ester; free radical scavenging activity; hydroxycinnamic acids
Mild pyrolysis (228 °C, 15 min) of rosmarinic, chlorogenic, and caffeic acids increased their antioxidative efficacy in a biological rat liver membrane assay by 4-, 11-, and 460-fold, respectively. The active components in the caffeic acid pyrolysates were identified as the recently isolated novel tetraoxygenated 1,3-cis- and 1,3-trans-phenylindan isomers, which showed comparable IC50 values (0.041 and 0.04 μM, respectively) and were 8-fold more active than butylated hydroxytoluene (BHT). Comparison of nonroasted, light-roasted, and dark-roasted coffee extracts showed that the degree of roasting is positively correlated to the inhibition of lipid peroxidation in rat liver membranes. The potent reducing properties of the phenylindan isomers resulted in (a) prooxidative effects at relatively higher concentrations in an ethyl linoleate peroxidation assay, and (b) promotion of hydroxylation of 2‘-deoxyguanosine to afford 8-oxo-2‘-deoxyguanosine. However, the results of the rat liver homogenate model system show that pyrolysis of caffeic acid and its esters chlorogenic acid and rosmarinic acid can procure potent antioxidants and underlines the potential use of heat processing to generate novel bioactive molecules. Keywords: Caffeic acid; phenylindan isomers; antioxidants, prooxidants; polyphenols; lipid peroxidation
Theaflavin and its galloyl esters are polyphenolic pigments of black tea. In the course of studies on the oxidation mechanism of tea polyphenols, two theaflavin oxidation products named bistheaflavins A and B were isolated, and their structures were elucidated on the basis of MS and NMR spectroscopic analyses. Treatment of a mixture of (−)-epicatechin and (−)-epigallocatechin with banana fruit homogenate yielded bistheaflavin A together with theaflavin and theanaphthoquinone. The symmetrical structure of bistheaflavin A suggested that this compound was formed by oxidative C−C coupling of two theaflavin molecules. In contrast, theaflavin in phosphate buffer (pH 7.3) was gradually oxidized to give bistheaflavin B and theanaphthoquinone. Bistheaflavin B possesses a bicyclooctane skeleton probably formed by intermolecular cyclization between dehydrotheaflavin and dihydrotheanaphthoquinone. Keywords: Theaflavin; oxidation; intermolecular cyclizatiion; black tea; polyphenol; catechin
Methods are described for the fractionation of the complex mixture of phenolic substances and their oxidation products occurring in manufactured tea. Products of oxidation detected include two fractions, S I and S II, responsible for the greater part of the colour intensity of a tea infusion, and nine unidentified substances, A, B, C, D, P, Q, X, Y and Z. S I and S II have been obtained almost free from other contaminants. They have acidic properties, and mean molecular weights of the order 600. They are probably mixtures of dimers, each dimer consisting of two oxidized flavanol units. X and Y have no acidic properties and are also distinguished from S I and S II by several characteristic colour reactions. P may be an anthocyanidin.
( - )-Epicatechin-3-O-gallate (ECG), one of the major green tea poly-phenols, was oxidised chemically using potassium ferricyanide. The major oxidation product, termed theaflavate A, which gave a sharp peak on HPLC analysis, was separated and purified by a combination of chromatography on Sephadex LH-20 and a semi-preparative HPLC method. This compound was characterised by NMR spectroscopy (1H, 13C, HMQC, HMBC and ROESY) and mass spectrometry (Electrospray method) and was found to have a novel benzotropolone skeleton formed between the B-ring of one ECG molecule and the galloyl ester group of another. Compounds containing this type of benzotropolone link were also found to be present in black tea. This benzotropolone link is of great interest, since it shows that the galloyl ester groups of flavan-3-ols participate in oxidative condensation reactions. This illustrates the complexity of theaflavin-type compounds in black tea and provides an additional reaction pathway for the formation of thearubigins which has not been previously considered. © 1997 SCI
This paper summarises the occurrence in foods and beverages of the cinnamic acids, their associated conjugates and transformation products. Quantitative data are lacking for some commodities known to contain them, but it is clear that for many people coffee will be the major source. The daily dietary intake of total cinnamates may vary substantially from almost zero to perhaps close to 1 g. The data relating to their absorption and metabolism are presented along with a consideration of their possible in vivo effects. Data for true bioavailability are incomplete: in particular it is not clear whether availability differs markedly with the form of the conjugate, and whether as a consequence some dietary sources may be superior to others.
Theasinensins A and D are B,B′-linked dimers of (−)-epigallocatechin 3-O-gallate connected through R and S biphenyl bonds, respectively, and are major constituents of black tea. Enzymatic oxidation of epigallocatechin 3-O-gallate produced dehydrotheasinensin A, and the structure was shown to be equivalent to an o-quinone of theasinensin A. When the aqueous solution of dehydrotheasinensin A was heated, theasinensin D was produced along with galloyl oolongtheanin. On the other hand, dehydrotheasinensin A was converted to theasinensins A and D along with oxidation products in phosphate buffer at pH 6.8 at room temperature. The results strongly suggested that theasinensins in black tea were produced by oxidation–reduction dismutation of dehydrotheasinensin.
The reactions of (−) epicatechin (I) and (−) epicatechin gallate (II) with gallic acid in a model tea fermentation system were studied. The primary oxidation products formed from the oxidation of (I) or (II) with gallic acid in short reaction periods were bright red condensation products named epitheaflavic acid (IX) and 3-galloyl epitheaflavic acid (X). (IX) and (X) appear to be identical to an unknown 'complex Q' reported earlier to be a trace substance in black tea extracts. Both (I) and (II) were oxidized in the model tea fermentation system, but gallic acid was not oxidized by itself. Oxidation of (I) in this system did not produce any (IX) unless gallic acid was also present. Some deesterification of (II) took place in the model tea fermentation system with the result that oxidation of (II) by this system produced some (IX) and some (X) besides other oxidation products. (IX) was not reactive in the model tea fermentation system by itself, but (IX) was rapidly transformed to thearubigins (acidic brown pigments found in black tea) when (I) was also present. These results furnish more information regarding the mechanism by which the thearubigins of black tea are formed, and they point out again the central role of tea flavanol oxidation catalysed by tea catechol oxidase in tea fermentation.
Three new polyphenolic compounds, theaflavate B, isotheaflavin-3'-O-gallate and neotheaflavin-3- O-gallate, have been characterised in extracts from black tea (the fermented leaves of Camellia sinensis). The structures of these compounds were determined using 1D and 2D NMR spectroscopy, mass spectrometry and chemical oxidation of catechin precursors. Theaflavate B contains a benzotropolone moiety produced from oxidation of the galloyl ester group of a flavan-3-O-gallate and as such represents a new class of polyphenol pigments obtained from black tea. 1998 Elsevier Science Ltd. All rights reserved.
Sensory-guided fractionation of a roasted coffee brew by means of sequential solvent extraction, ultrafiltration, and RP-HPLC
demonstrated a group of ethyl acetate soluble compounds formed from O-hydroxycinnamoyl quinic acid derivatives upon coffee roasting as the key compounds contributing to the bitter taste of roasted
coffee beverages. LC-MS/MS studies, 1D- and 2D-NMR spectroscopy, syntheses, and model roast experiments with 5-O-caffeoyl- and 5-O-feruloylquinic acid led to the unequivocal identification of 3-O-caffeoyl-γ-quinide (2a), 4-O-caffeoyl-γ-quinide (3a), 5-O-caffeoyl-epi-δ-quinide (4a), 4-O-caffeoyl-muco-γ-quinide (5a), 5-O-caffeoyl-muco-γ-quinide (6a), 3-O-feruloyl-γ-quinide (2b), and 4-O-feruloyl-γ-quinide (3b) as intense coffee bitter tastants. Besides these individual bitter compounds, a highly complex and intensely bitter HPLC
fraction was isolated from the ethyl acetate extractables of coffee brew. Application of COSY spectroscopy and alkaline hydrolytic
degradation gave strong evidence that the bitter taste of that fraction is due to a multiplicity of rather complex quinic
acid lactone isomers multiply esterified with p-coumaric acid, caffeic acid, ferulic acid, 3,4-dimethoxycinnamic acid, and quinic acid, respectively. As representatives
of this fraction, 3,4-O-dicaffeoyl-γ-quinide (10), 3,5-O-dicaffeoyl-epi-δ-quinide (11), and 4,5-O-dicaffeoyl-muco-γ-quinide (12) have been isolated, purified, and identified as strongly bitter-tasting compounds in roasted coffee. For the first time,
bitter taste recognition thresholds were determined for the individual compounds showing that, strongly depending on their
chemical structure, the bitter threshold levels ranged between 9.8 and 180μmol/l (water).
α-Dicarbonyl compounds, namely glyoxal (GO), methylglyoxal (MGO) and 3-deoxyglucosone (3-DOG), as well as 5-(hydroxymethyl)-2-furfural (5-HMF) were found and measured in carbonated soft drinks (CSD). It was realized that high fructose corn syrup (HFCS) in regular CSDs was the major source of α-dicarbonyl compounds in beverages after comparison of levels in regular and diet CSDs. In two most commonly used HFCS formulas, 42% and 55% HFCS, the highest level of dicarbonyl found was 3-DOG, followed by MGO, and then GO. The stability of dicarbonyls in CSDs containing HFCS and (−)-epigallocatechin gallate (EGCG) which were incubated at 35 and 45 °C was investigated. It was found that EGCG decreased from 1 mg/mL to 0.5 and 0.3 mg/mL for 35 and 45 °C, respectively, in 16 days storage. Moreover, the reactions of EGCG with MGO, 3-DOG and 5-HMF were observed from the comparison of storage CSDs with and without EGCG under acidic conditions.
Cell suspension cultures of E. distachya produced three acylamino acids. Nα-Malonyl-l-tryptophan was isolated along with 5′-S-methyl-5′-thioadenosine and stigmast-4-ene-3-one from normally cultured cells, while the production of p-coumaroylglycine, p-coumaroyl-d-alanine and cinnamic acid was induced by the addition of yeast extract to the early stationary phase of cultures.
Of the thearubigins associated with black tea, those which are extracted from aqueous black tea liquor have been degraded to flavan-3-ols, flavan-3-ol gallates, anthocyanidins, and gallic acid. These results establish that the thearubigins are polymeric proanthocyanidins.
Tea catechins undergo many chemical changes such as oxidation and epimerisation during the course of the manufacturing and brewing processes. In the production of green tea, the oxidation is limited by inactivating the enzymic activity in freshly picked tea leaves by firing or steaming. As a result, epimerisation of the catechins is thought to be one of the most important reactions in the manufacture of green tea. The epimerisation of catechins in green tea infusions using both purified water and tap water at different temperatures has been investigated by HPLC and is reported in the present paper. Individual catechins can undergo epimerisation at high temperatures; however, in green tea infusions, the predominant change appears to be epimerisation from the epistructure to the nonepistructure. It has been found that this epimerisation takes place more easily in tap water than in purified water. The complexity of the ions present in the tap water together with the difference in pH between tap and purified water are thought to be the main factors influencing this observation. In the infusion brewed with tap water, the catechins are easily epimerised and then rapidly degraded. Stability studies on catechins in green tea strong infusions, which were prepared with a mixture of ethanol and purified water, in the ratio of tea leaves to solvent 1:5 (w/v), have shown that epimerisation can be observed at 40°C after a few days storage. Therefore, it is thought that not only temperature, but also heating time influences the epimerisation of catechins in green tea infusions.
Ring structure-reactivity relationships of three flavan-3-ols [epicatechin (EC), epicatechin gallate (ECG), and epigallocatechin gallate (EGCG)] and three simple phenolic compounds (1,3,5-trihydroxybenzene, 1,2,3-trihydroxybenzene, and methylgallate as the analogous individual A, B, and C benzene rings of EGCG) on product generation in an aqueous glucose-glycine reaction model system (125 degrees C and 30 min) were investigated. The addition of EC, ECG, or EGCG to a glucose-glycine model was reported to similarly significantly reduce the formation of pyrazine, methyl-substituted pyrazines, and cyclotene. All three flavan-3-ols were also reported to generate phenolic-C2, C3, C4, and C6 sugar fragment adducts and to statistically reduce the concentration of glyoxal, glycolaldehyde, methylglyoxal, hydroxyacetone, diacetyl, acetoin, and 3-deoxyglucosone during the reaction time course, except for the EGCG reaction where 3-deoxyglucosone was not statistically different from the control after 20 min. For the simple phenolic compounds, methylgallate followed by 1,2,3-trihydroxybenzene was the least reactive, while 1,3,5-trihydroxybenzene was reported as the most reactive phenolic structure for quenching or reducing the concentration of the alpha-hydroxy- and alpha-dicarbonyl sugar fragments during the reaction time course. These results imply that the main mechanism flavan-3-ols reduced product generation was phenolic-sugar fragment carbonyl trapping reactions primarily on the A ring (the meta-polyhydroxylated benzene ring) or not due to the alteration of the reaction reduction potential.
Recent investigations on the bitterness of coffee as well as 5- O-caffeoyl quinic acid roasting mixtures indicated the existence of another, yet unknown, bitter lactone besides the previously identified bitter compounds 5- O-caffeoyl- muco-gamma-quinide, 3- O-caffeoyl-gamma-quinide, 4- O-caffeoyl- muco-gamma-quinide, 5- O-caffeoyl- epi-delta-quinide, and 4- O-caffeoyl-gamma-quinide. In the present study, this orphan bitter lactone was isolated from the reaction products generated by dry heating of 5- O-caffeoylquinic acid model, and its structure was determined as the previously unreported 3- O-caffeoyl- epi-gamma-quinide by means of liquid chromatography-mass spectrometry (LC-MS) and one-/two-dimensional NMR experiments. The occurrence of this bitter lactone, exhibiting a low bitter recognition threshold of 58 micromol/L, in coffee beverages could be confirmed by LC-MS/MS (negative electrospray ionization) operating in the multiple reaction monitoring mode.
Epidemiological evidence indicates that avoidance of smoking, increased consumption of fruits and vegetables, and control of infections will have a major effect on reducing rates of cancer. Other factors include avoidance of intense sun exposure, increases in physical activity, and reduction of alcohol consumption and possibly red meat. A substantial reduction in breast cancer is likely to require modification of sex hormone levels, and development of practical methods for doing so is a high research priority. Resolution of the potential protective roles of specific antioxidants and other constituents of fruits and vegetables deserves major attention. Mechanistic studies of carcinogenesis indicate an important role of endogenous oxidative damage to DNA that is balanced by elaborate defense and repair processes. Also key is the rate of cell division, which is influenced by hormones, growth, cytotoxicity, and inflammation, as this determines the probability of converting DNA lesions to mutations. These mechanisms may underlie many epidemiologic observations.
The antioxidant components of cacao liquor, which is a major ingredient of chocolate, were isolated with column chromatography and high-performance liquid chromatography. Quercetin and its glucoside were identified by spectrometric methods. Clovamide and deoxyclovamide were characterized by (1)H and (13)C NMR and MS spectrometry. Their antioxidative activity was measured by peroxide value of linoleic acid and thiobarbituric acid reactive-substance value of erythrocyte ghost membranes and microsomes. In the bulk oil system, clovamide had the strongest antioxidative activity but was less active in the other experiments. In the case of the two hydrophilic systems, flavans such as quercetin and epicatechin were more potently effective than the glucosides. It is considered that chocolate is stable against oxidative deterioration due to the presence of these polyphenolic compounds.
The polyphenolic, flavonoid, and caffeine compositions of four commercial tea bag products (typical of those used in the UK, US, continental Europe, and the Middle East) and beverages prepared from them under a range of typical consumer use conditions have been studied. Leaf composition was determined by extraction with aqueous methanol: the absolute compositions of all four products were remarkably similar in terms of most phenolic compounds. The flavonoids comprised the major proportion (93-94%) of the total phenolics estimated by the Folin-Ciocalteu method. At brew times up to 2 min the composition of the brew solids was for each product practically independent of brew time, with flavonoids again comprising the major proportion (86-88%) of the total phenolics. The efficiency of extraction in brewing of total phenolics, total flavonoids, catechins, and theaflavins was up to 35-55% of the total available in the leaf, whereas the flavonol and flavone glycosides and caffeine were more efficiently extracted (up to 55-90%). The contribution of tea to the UK adult average total dietary intake of flavonols and flavones was calculated to be up to 80% depending on brewing conditions.
Green tea cateachins (GTC). namely (-) epicatechin (EC), (-) epicatechin gallate (ECG), (-) epigallocatechin (EGC), and (-) epigallocatechin gallate (EGCG), have been studied extensively for their wide-ranging biological activities. The goal of the present study was to examine the stability of GTC as a mixture under various processing conditions. The stability study demonstrated that GTC was stable in water at room temperature. When it was brewed at 98 degrees C for 7 h, longjing GTC degraded by 20%. When longjing GTC and pure EGCG were autoclaved at 120 degrees C for 20 min, the epimerization of EGCG to (-) gallocatechin gallate (GCG) was observed. The relatively high amount of GCG found in some tea drinks was most likely the epimerization product of EGCG during autoclaving. If other ingredients were absent, the GTC in aqueous solutions was pH-sensitive: the lower the pH, the more stable the GTC during storage. When it was added into commercially available soft drinks or sucrose solutions containing citric acid and ascorbic acid, longjing GTC exhibited varying stability irrespective of low pH value. This suggested that other ingredients used in production of tea drinks might interact with GTC and affect its stability. When canned and bottled tea drinks are produced, stored, and transported, the degradation of GTC must be taken into consideration.
An isocratic HPLC procedure was developed for the simultaneous determination of caffeine and six catechins in tea samples. When 31 commercial teas extracted by boiling water or 75% ethanol were analyzed by HPLC, the levels of (-)-epigallocatechin 3-gallate (EGCG), and total catechins in teas were in the order green tea (old leaves) > green tea (young leaves) and oolong tea > black tea and pu-erh tea. Tea samples extracted by 75% ethanol could yield higher levels of EGCG and total catechins. The contents of caffeine and catechins also have been measured in fresh tea leaves from the Tea Experiment Station in Wen-Shan or Taitung; the old tea leaves contain less caffeine but more EGCG and total catechins than young ones. To compare caffeine and catechins in the same tea but manufactured by different fermentation processes, the level of caffeine in different manufactured teas was in the order black tea > oolong tea > green tea > fresh tea leaf, but the levels of EGCG and total catechins were in the order green tea > oolong tea > fresh tea leaf > black tea. In addition, six commercial tea extracts were used to test the biological functions including hydroxyl radical scavenging, nitric oxide suppressing, and apoptotic effects. The pu-erh tea extracts protected the plasmid DNA from damage by the Fenton reaction as well as the control at a concentration of 100 microg/mL. The nitric oxide suppressing effect of tea extracts was in the order pu-erh tea >/= black tea > green tea > oolong tea. The induction of apoptosis by tea extract has been demonstrated by DNA fragmentation ladder and flow cytometry. It appeared that the ability of tea extracts to induce HL-60 cells apoptosis was in the order green tea > oolong > black tea > pu-erh tea. All tea extracts extracted by 75% ethanol have stronger biological functions than those extracted by boiling water.
The objective of this study was to investigate the inhibitory effect of naturally occurring flavonoids on individual stage of protein glycation in vitro using the model systems of delta-Gluconolactone assay (early stage), BSA-methylglyoxal assay (middle stage), BSA-glucose assay, and G.K. peptide-ribose assay (last stage). In the early stage of protein glycation, luteolin, qucertin, and rutin exhibited significant inhibitory activity on HbA1C formation (p < 0.01), which were more effective than that of aminoguanidine (AG, 10 mM), a well-known inhibitor for advanced glycation endproducts (AGEs). For the middle stage, luteolin and rutin developed more significant inhibitory effect on methylglyoxal-medicated protein modification, and the IC50's were 66.1 and 71.8 microM, respectively. In the last stage of glycation, luteolin was found to be potent inhibitors of both the AGEs formation and the subsequent cross-linking of proteins. In addition, phenyl-tert-butyl-nitron served as a spin-trapping agent, and electron spin resonance (ESR) was used to explore the possible mechanism of the inhibitory effect of flavonoids on glycation. The results indicated that protein glycation was accompanied by oxidative reactions, as the ESR spectra showed a clear-cut radical signal. Statistical analysis showed that inhibitory capability of flavonoids against protein glycation was remarkably related to the scavenging free radicals derived from glycoxidation process (r = 0.79, p < 0.01). Consequently, the inhibitory mechanism of flavonoids against glycation was, at least partly, due to their antioxidant properties.
Mechanisms of how epicatechin alters the pathways of the Maillard reaction were investigated. Carbon-13 and nitrogen-15 labeling studies were utilized to define the reactivity of epicatechin with glucose, glycine, and/or reaction products in an aqueous model (pH 7, 125 degrees C for 30 min) via GC, GC/MS and HPLC/MS analysis. Quantification of the volatile reaction product isotopomers by GC/MS from a 1:1 labeled to unlabeled glucose (carbohydrate module labeling technique) plus glycine model system indicated the formation of 2,3-butanedione and acetol were primarily formed via intact C4 and C3 sugar fragments, whereas pyrazine, methylpyrazine, 2,5-dimethylpyrazine, 2,3,5-trimethylpyrazine, and cyclotene were primarily formed via intact C2/C2, C2/C3, C3/C3, C3/C3, and C3/C3 sugar fragment pairs, respectively. The formation of these seven compounds was also reported by GC analysis to be dramatically inhibited when epicatechin was added to the glucose/glycine model system (observed 9-113-fold reduction). HPLC/MS analysis of both the glucose-labeled and glycine-labeled model systems with and without epicatechin indicated that epicatechin reacted directly with C2, C3, and C4 sugar fragments, while epicatechin did not report any direct reactivity with glycine. In conclusion, the quenching of sugar fragmentation products via epicatechin was correlated with the observed inhibition on volatile compound formation when epicatechin was added to a glucose/glycine aqueous reaction model system.
Sequential application of solvent extraction, gel permeation chromatography, and RP-HPLC in combination with taste dilution analyses, followed by LC-MS and 1D/2D-NMR experiments and thiolytic degradation, revealed that, besides theobromine and caffeine, the flavan-3-ols epicatechin, catechin, procyanidin B-2, procyanidin B-5, procyanidin C-1, [epicatechin-(4beta-->8)](3)-epicatechin, and [epicatechin-(4beta-->8)](4)-epicatechin were among the key compounds contributing to the bitter taste as well as the astringent mouthfeel imparted upon consumption of roasted cocoa. In addition, a series of quercetin, naringenin, luteolin, and apigenin glycopyranosides as well as a family of not previously identified amino acid amides, namely, (+)-N-[4'-hydroxy-(E)-cinnamoyl]-L-aspartic acid, (+)-N-[3',4'-dihydroxy-(E)-cinnamoyl]-L-aspartic acid, (-)-N-[3',4'-dihydroxy-(E)-cinnamoyl]-L-glutamic acid, (-)-N-[4'-hydroxy-(E)-cinnamoyl]-L-glutamic acid, (-)-N-[4'-hydroxy-(E)-cinnamoyl]-3-hydroxy-L-tyrosine, (+)-N-[4'-hydroxy-3'-methoxy-(E)-cinnamoyl]-L-aspartic acid, and (+)-N-(E)-cinnamoyl-L-aspartic acid, have been identified as key astringent compounds of roasted cocoa. Furthermore, (-)-N-[3',4'-dihydroxy-(E)-cinnamoyl]-3-hydroxy-l-tyrosine (clovamide), (-)-N-[4'-hydroxy-(E)-cinnamoyl]-L-tyrosine (deoxyclovamide), and (-)-N-[3',4'-dihydroxy-(E)-cinnamoyl]-L-tyrosine, reported previously as antioxidants, have been found as contributors of cocoa's astringent taste. By means of the half-tongue test, the taste thresholds of flavan-3-ols and glycosides have been determined.
In the current study, we have focused on isolation and detection of major radical oxidation products from theaflavin in order to better understand antioxidation mechanisms of this compound. Theanaphthoquinone was identified as a major oxidation product of theaflavin from two different oxidant model systems: DPPH and peroxidase/hydrogen peroxide. This result indicated that the benzotropolone moiety in theaflavin may play an important role in its antioxidant properties. The stability of theaflavin was studied in varying pH solutions: simulated gastric juice and buffer solutions of pH 5.5, pH 7.4, and pH 8.5. The results indicated that theaflavin is unstable in alkaline conditions, while it was stable in acidic conditions. Theanaphthoquinone was identified as an autoxidation product of theaflavin during its stability study in alkaline conditions.
We pooled the data from 6 case-control studies of bladder cancer with detailed information on fluid intake and water pollutants, particularly trihalomethanes (THM), and evaluated the bladder cancer risk associated with total and specific fluid consumption. The analysis included 2,729 cases and 5,150 controls. Odds ratios (OR) and 95% confidence intervals (CI) for fluid consumption were adjusted for age, gender, study, smoking status, occupation and education. Total fluid intake was associated with an increased risk of bladder cancer in men. The adjusted OR for 1 l/day increase in intake was 1.08, (95% CI 1.03-1.14, p-value for linear trend <0.001), while no trend was observed in women (OR=1.04, 0.94-1.15; p-value=0.7). OR was 1.33 (1.12-1.58) for men in the highest category of intake (>3.5 l/day) as compared to those in the lowest (<or=2 l/day). An increased risk was associated with intake of tap water. OR for >2 l/day vs. <or=0.5 l/day was 1.46 (1.20-1.78), with a higher risk among men (OR=1.50, 1.21-1.88). No increased risk was observed for the same intake groups of nontap water in men (OR=0.97, 0.77-1.22) or in women (OR=0.85, 0.50-1.42). Increased bladder cancer risks were observed for an intake of >5 cups of coffee daily vs. <5 and for THM exposure, but neither exposure confounded or modified the OR for tap water intake. The association of bladder cancer with tap water consumption, but not with nontap water fluids, suggests that carcinogenic chemicals in tap water may explain the increased risk.
(-)-Epigallocatechin-3-gallate (EGCG), the most abundant and biologically active compound in tea, has been extensively studied for its activities related to disease prevention in animal models and in vitro. However, its stability under different experimental conditions has not been well-characterized. In the present study, the stability of EGCG in animal drinking fluid and under cell culture conditions and the factors that affect its stability under these conditions were investigated. Our results demonstrated that auto-oxidation and epimerization are the two major reactions causing the instability of EGCG. The structures of the major oxidation products, EGCG dimers, were identified. The rates of these reactions were affected by the temperature, pH, the partial pressure of oxygen, the level of antioxidants, the concentration of EGCG, and other components of tea. In future studies with EGCG, its stability should be considered in order to avoid possible artifacts.
Aimed at defining the key drivers for the quality-determining umami taste of a high-grade powdered green tea, called mat-cha, a bioactivity-guided fractionation using solvent extraction, solvent precipitation, preparative chromatographic separations, and human psychophysical experiments was applied on freshly prepared mat-cha. Liquid chromatography-tandem mass spectrometry and one-/two-dimensional nuclear magnetic resonance studies on isolated fractions led to the identification of l-theanine, succinic acid, 3,4,5-trihydroxybenzoic acid (gallic acid), and (1R,2R,3R,5S)-5-carboxy-2,3,5-trihydroxycyclohexyl-3,4,5-trihydroxybenzoate (theogallin) as umami-enhancing compounds in the green tea beverage, and it can be shown by sensory studies that these compounds are able to raise the umami intensity of sodium l-glutamate proportionally.
Since recent reports on the role of N-phenylpropenoyl-L-amino acids as powerful antioxidants and key contributors to the astringent taste of cocoa nibs, there is an increasing interest in the concentrations of these phytochemicals in plant-derived foods. A versatile analytical method for the accurate quantitative analysis of N-phenylpropenoyl-L-amino acids in plant-derived foods by means of HPLC-MS/MS and synthetic stable isotope labeled N-phenylpropenoyl-L-amino acids as internal standards was developed. By means of the developed stable isotope dilution assay (SIDA), showing recovery rates of 95-102%, 14 N-phenylpropenoyl-L-amino acids were quantified for the first time in cocoa and coffee samples. On the basis of the results of LC-MS/MS experiments as well as cochromatography with the synthetic reference compounds N-[3',4'-dihydroxy-(E)-cinnamoyl]-L-tryptophan, N-[4'-hydroxy-(E)-cinnamoyl]-L-tryptophan, and N-[4'-hydroxy-3'-methoxy-(E)-cinnamoyl]-L-tyrosine, respectively, were detected for the first time in cocoa powder, and (-)-N-[4'-hydroxy-(E)-cinnamoyl]-L-tyrosine, (-)-N-[3',4'-dihydroxy-(E)-cinnamoyl]-L-tyrosine, N-[4'-hydroxy-3'-methoxy-(E)-cinnamoyl]-L-tyrosine, (+)-N-[3',4'-dihydroxy-(E)-cinnamoyl]-L-aspartic acid, (+)-N-[4'-hydroxy-(E)-cinnamoyl]-L-aspartic acid, N-[3',4'-dihydroxy-(E)-cinnamoyl]-L-tryptophan, N-[4'-hydroxy-(E)-cinnamoyl]-L-tryptophan, and N-[4'-hydroxy-3'-methoxy-(E)-cinnamoyl]-L-tryptophan, respectively, were detected for the first time in coffee beverages.
The carbonyl stress that leads to the formation of advanced glycation end products (AGEs) in diabetes mellitus has drawn much attention recently. Reactive alpha-dicarbonyl compounds, such as glyoxal (GO) and methylglyoxal (MGO), have been shown to be a high potential glycation agent in vitro and in vivo. In this study, epicatechins in green tea and theaflavins in black tea were found to be able to reduce the concentration of MGO in physiological phosphate buffer conditions. Modified MGO derivatization for GC/flame ionization detector (FID) method in quantification was systematically conducted. In molar ratio of 3 (MGO/polyphenol), theaflavin-3,3'-digallate (TF3) in theaflavins and (-)-epigallocatechin (EGC) in epicatechins showed the highest MGO reduction at 66.65 and 45.74%, respectively, after 1 h of incubation. In kinetic study (molar ratio of MGO/polyphenol = 1:1), rapid MGO reduction occurred within 10 min. Identities of primary adducts between (-)-epigallocatechin gallate (EGCG) and MGO were determined. Newly generated stereoisomers at the C8 position of EGCG A-ring were isolated with a chiral column, and structurally confirmed by 2-D NMR analyses.
Aimed at elucidating intense bitter-tasting molecules in coffee, various bean ingredients were thermally treated in model experiments and evaluated for their potential to produce bitter compounds. As caffeic acid was found to generate intense bitterness reminiscent of the bitter taste of a strongly roasted espresso-type coffee, the reaction products formed were screened for bitter compounds by means of taste dilution analysis, and the most bitter tastants were isolated and purified. LC-MS/MS as well as 1-D/2-D NMR experiments enabled the identification of 10 bitter compounds with rather low recognition threshold concentrations ranging between 23 and 178 micromol/L. These bitter compounds are the previously unreported 1,3-bis(3',4'-dihydroxyphenyl) butane, trans-1,3-bis(3',4'-dihydroxyphenyl)-1-butene, and eight multiply hydroxylated phenylindanes, among which five derivatives are reported for the first time. In addition, the occurrence of each of these bitter compounds in a coffee brew was verified by means of LC-MS/MS (ESI-) operating in the multiple reaction monitoring (MRM) mode. The structures of these bitter compounds show strong evidence that they are generated by oligomerization of 4-vinylcatechol released from caffeic acid moieties upon roasting.
Green tea, tara tannin, and tannic acid have been profiled for their contents of galloylquinic acids using LC-MS8. These procedures have provided evidence for the first observation of (i) 1-galloylquinic acid (11), 1,3,5-trigalloylquinic acid (22), 4-(digalloyl)quinic acid (28), 5-(digalloyl)quinic acid (29), and either 3-galloyl-5-(digalloyl)quinic acid (32) or 3-(digalloyl)-5-galloylquinic acid (33) from any source; (ii) 4-galloyl-5-(digalloyl)quinic acid (34), 5-galloyl-4-(digalloyl)quinic acid (35), 3-(digalloyl)-4,5-digalloylquinic acid (41), 4-(digalloyl)-3,5-digalloylquinic acid (40), 5-(digalloyl)-3,4-digalloylquinic acid (39), and 1,3,4-trigalloylquinic acid (21) from tara tannin; and (iii) 3-galloylquinic acid (12) and 4-galloylquinic acid (14) from green tea. The first mass spectrometric fragmentation data are reported for galloylquinic acids containing between five and eight gallic acid residues. For each of these mass ranges at least two isomers based on the 1,3,4,5-tetragalloylquinic acid core (25) and at least three based on the 3,4,5-trigalloylquinic acid core (24) were observed. Methanolysis of tara tannin yielded methyl gallate, methyl digallate, and methyl trigallate, demonstrating that some of these galloylquinic acids contained at least one side chain of up to four galloyl residues.