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Studies on the anti-diabetic and hypolipidemic potentials of mangiferin (Xanthone Glucoside) in streptozotocin-induced Type 1 and Type 2 diabetic model rats
Abstract and Figures
Context: Mangifera indica (Anacardiaceae) stem bark contains a rich content of mangiferin and is used traditionally in Indian Ayurvedic system to treat diabetes. Purpose of the study: To investigate anti-diabetic and hypolipidemic effects of mangiferin in type 1 and type 2 diabetic rats models. Streptozotocin was used to induce type 1 and type 2 diabetic rats. Mangiferin (at a dose 10 and 20mg/kg) was administrated intra-peritoneally in type 1 and type 2 diabetic rats daily up to 30 days. Biochemical parameters notably fasting blood sugar, total cholesterol, triglycerides, low-density lipoprotein, very low-density lipoprotein and high-density lipoprotein were estimated. In addition, in vitro alpha amylase and alpha glucosidase inhibitory effects of mangiferin were performed and IC 50 values were determined. Results: Mangiferin exhibited significant (P<0.05) anti-diabetic as well as hypolipidemic effects by lowering FBS, TC, TG, LDL, and VLDL levels; but also with elevation of HDL level in type 2 diabetic model rats. In addition, mangiferin showed appreciable alpha amylase inhibitory effect (IC 50 value 74.35±1.9µg/ml) and alpha glucosidase inhibitory effect (IC 50 41.88±3.9µg/ml) when compared with standard drug acarbose (IC 50 83.33±1.2µg/ml). Conclusions: Mangiferin showed anti-diabetic as well as hypolipidemic potentials in type 2 diabetic model rats. Therefore, mangiferin possess beneficial effects in the management of type 2 diabetes with hyperlipidemia.
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... Tannins were also reported as potent inhibitors of α-amylase' [52], while IC 50 of 23.05 mg/mL was obtained for phenolic compounds [53]. Also, a lower IC 50 of 83.72 mg/ mL was obtained for the inhibition of α-amylase by alkaloids [54]. Likewise, terpenoids have been reported to have α-amylase inhibitory properties [55]. ...
... In detail, α-Amylase and α-Glucosidase are enzymes that foster carbohydrate digestion, thereby increasing the postprandial glucose level in diabetic patients; hence, inhibiting these enzymes can be a management option against diabetes [53,54]. In the same vein, acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) are key enzymes in several neurological disorders. ...
Background
Medicinal plant contains multiple bioactive compounds with therapeutic potentials. Due to their availability, affordability, and minimal known side effects, they are widely practiced. Identification, quantification, and establishment of their interaction with physiological enzymes help in the standardization of plant-based medicinal extracts. In this study, gas chromatography/flame ionization detector (GC–FID) and high-performance liquid chromatography (HPLC) analysis were used to determine the bioactive components in the ethanol extract of Newbouldia laevis stem bark. The antioxidant activity of the extract was determined. Enzyme inhibitory potency of the flavonoids’ components was investigated against acetylcholinesterase, butyrylcholinesterase, phospholipase A2, α-glucosidase, and α-amylase.
Results
Analysis of ethanol extract of N. laevis stem-bark revealed alkaloids (0.37%), tannins (1.82 mg/TEq/g), flavonoids (5.85 mg/QEq), steroids (0.11 mg/10 g) and glycosides (0.08 mg/10 g). The HPLC fingerprint of flavonoids showed high concentrations (mg/100 g) of catechin (47.11), apigenin (15.68), luteolin (18.90), kaempferol (41.54), and quercetin (37.64), respectively. In vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging ability of the extract was exhibited at 150 and 200 mg/mL, respectively. At 300 mg, most in vitro antioxidant potentials (lipid peroxidation, metal chelating ability, hydroxyl, nitric oxide, sulfide oxide radicals scavenging abilities) were obtained. The extract showed varying inhibitory abilities (> 50%) on acetylcholinesterase, butyrylcholinesterase, phospholipase A2, α-glucosidase and α-amylase at 300 mg/mL, IC 50 of 129.46, 237.10, 169.50, 251.04 and 243.06 mg/mL, respectively, with inhibition constants (Ki) of 3.92, 1.63, 1.11, 2.95 and 2.11. Results showed an affinity for the targeted enzymes with free energies higher than the standard drugs.
Conclusion
The results revealed that the N. laevis stem bark possesses antioxidant activity and enzyme inhibitory activity on the physiological enzyme that has been implicated in diabetes. In vitro and in silico inhibition of these physiological enzymes by extract suggests that the stem bark can be effective in ameliorating the complications associated with diabetes mellitus.
... The carbons of the A ring (acetate pathway) of xanthones are numbered 1-4, while the B ring (shikimate pathway) is numbered 5-8 ( Figure 4) [95]. There are many reports on numerous pharmacological activities attributed to xanthones of natural origin, including anti-inflammatory [96,97], anti-Leptospira [98], anticollagenase, anti-elastase, anti-hyaluronidase, anti-tyrosinase [99], anticancer [100,101], antidiabetic [102,103], and antifungal [104] activities, and many xanthones have been described as good bacterial inhibitors [105][106][107][108]. ...
... From the stems of the same plant species, the isolation of prenylated xanthone assiguxanthone B (26) ( Figure 5) was reported, which proved efficient against S. aureus (ATCC 25923) and B. subtilis (ATCC 6623), with MICs of 100 μg/mL and 25 μg/mL, respectively (Table 1) [24]. There are many reports on numerous pharmacological activities attributed to xanthones of natural origin, including anti-inflammatory [96,97], anti-Leptospira [98], anticollagenase, anti-elastase, anti-hyaluronidase, anti-tyrosinase [99], anticancer [100,101], antidiabetic [102,103], and antifungal [104] activities, and many xanthones have been described as good bacterial inhibitors [105][106][107][108]. ...
Phenolic compounds are natural substances that are produced through the secondary metabolism of plants, fungi, and bacteria, in addition to being produced by chemical synthesis. These compounds have anti-inflammatory, antioxidant, and antimicrobial properties, among others. In this way, Brazil represents one of the most promising countries regarding phenolic compounds since it has a heterogeneous flora, with the presence of six distinct biomes (Cerrado, Amazon, Atlantic Forest, Caatinga, Pantanal, and Pampa). Recently, several studies have pointed to an era of antimicrobial resistance due to the unrestricted and large-scale use of antibiotics, which led to the emergence of some survival mechanisms of bacteria to these compounds. Therefore, the use of natural substances with antimicrobial action can help combat these resistant pathogens and represent a natural alternative that may be useful in animal nutrition for direct application in food and can be used in human nutrition to promote health. Therefore, this study aimed to (i) evaluate the phenolic compounds with antimicrobial properties isolated from plants present in Brazil, (ii) discuss the compounds across different classes (flavonoids, xanthones, coumarins, phenolic acids, and others), and (iii) address the structure–activity relationship of phenolic compounds that lead to antimicrobial action.
... The findings of Dineshkumar et al., who observed that mangiferin had anti-diabetic and hypolipidemic potentials in type 2 diabetes model rats, are supported scientifically by our investigation. Consequently, mangiferin has beneficial effects in treating hyperlipidemia and type 2 diabetes (25). The plant's leaf extract may have an anti-diabetic effect due to mangiferin and other phytochemicals such as phenolic and flavonoid components. ...
Introduction: Diabetes mellitus is a metabolic disorder that has a number of allopathic treatments in practice which are having adverse side effects. Mangiferin and giloy are the important Ayurvedic medications. Both have effective control over diabetes glycemic status. It is possible that the treatment of certain herbal remedies led to an increase in intracellular Ca2+ levels or that glucose-stimulated insulin secretion was enhanced through activating glucose transporter-2 (GLUT-2) receptors. In our work, we rigorously examined the chemical and biological properties of giloy and mangiferin. Clinical study on the effect of mangiferin and giloy combined extract solution in type 2 diabetic subjects and determine the level of Fasting Blood sugar, insulin and HbA1c in type 2 diabetic subjects before and after therapy. Materials and Methods: A randomized cross-sectional study was conducted on type 2 diabetic subjects. Study design with group 1 diabetic subjects (n=45) of FBS less than or equal to 160 mg/dl) and diabetic subjects group 2 (n=49) of FBS more than 160 mg/dl were included with regular antidiabetic drugs; in addition, for the period 30 days, twice a day, 500 mg mangiferin and 500 mg giloy extract was given to group 1 and group 2. The difference between the groups was calculated using the t-test and Mann-Whitney U test. Results: It is evident from the statistical data a significant change seen in HbA1c levels , FBS levels and insulin values while comparing group 1 and group 2 diabetic subjects. However, in group 1 and group 2 creatinine levels did not show much change. Conclusion: Our study findings indicate that mangiferin and giloy extract is a better regime for the effective glycaemic control by an increase in insulin levels. Further, herbal leaf extract is a good natural source and cost-effective with no adverse side effects.
... The dried leaves were then blended and sieved with a B40 sieve to obtain Coffea arabica L. leaves powder with a uniform size. For sample extraction, 225 mg Coffea arabica L. leaves powder was extracted with petroleum ether (2 x 2 L, 6 h each time) to remove fatty matter, with cold acetone (4 x 2 L, 24 h each time) to remove tannins and finally with 70% ethanolic solvent (4 x 1 L, 6 h each time) (18). For sample preparation, 72 mg extract was diluted with 10 mL methanol and filtered with Whatman filter paper no.40. ...
Mangiferin is one of the antioxidants in Coffea arabica L. leaves that has many pharmacological effects. The content of secondary metabolites in the leaves including mangiferin can be affected by age. A Thin Layer Chromatography (TLC) method for the quantitative analysis of mangiferin in Coffea arabica L. leaves extract was developed and validated. The method was developed using a mobile phase prepared with analytical grade solvents: ethyl acetate, methanol, formic acid, and deionized water (8:2:1:1 v/v/v/v). Regression functions were established over the 199.98-600.00 ng/spot range with r=0.999. The limit of detection (LOD) and limit of quantification (LOQ) were 13.87 and 41.61 ng, respectively. The method was selective with a resolution value of more than 1.5 and specific with the spectra correlation value for purity and identity check of more than 0.99. The percentage RSD was found to be 2.43% for repeatability precision and 2.05% for intermediate precision. The method's accuracy was determined through the standard addition method by adding known quantities of standard mangiferin to the pre-analyzed test solution and the mean recovery was 101.69± 1,21%. This TLC Densitometry method was linear, sensitive, selective and specific, precise, accurate, and can be used for routine analysis of mangiferin. On the young Coffea arabica L. leaves, the concentration of mangiferin ± RSD was 0.830 ± 1.71% w/w, and on the old Coffea arabica L. leaves was 1.128± 1.59% w/w.
... The literature on xanthones reports that they represent an important class of compounds with a large number of biological activities documented like antimicrobial, antiviral, antiparasitic, anti-inflammatory, antioxidant, anti-HIV, antiulcer, antidiabetic, diuretic or analgesic activities and many others (Negi et al., 2011;Luo et al., 2013;Perrucci et al., 2006;Groweiss et al., 2000;Pinto et al., 2005;Dineshkumar et al., 2010). Additionally, among the plants identified as sources of xanthones (Table 1), some ethnopharmacological investigations of their extracts led to the conclusion that the bitterness of the Gentiananceae plant extracts, for instance, is due to the presence of xanthones while most of the Swertia extracts demonstrated mutagenic potency associated with the presence of xanthones (Morimoto et al., 1982). ...
The xanthones represent an important and widely spread class of specialized metabolites in the plant kingdom, fungi, and lichens. Their aromatic and highly oxygenated structures owe them the ability to undergo a series of chemical reactions to form an important number of derivatives as well as to exert a large scale of excellent activities that particularly increased their interest for several researchers. Amongst the reactions observed on their basic nucleus, C-glycosylation leads to the formation of C-glycosylxanthones, a rare subclass of xanthones encountered in nature. Until July 2023, the literature survey on chemical and pharmacological investigations of medicinal plants indicated that a total of 41 distinct natural C-glycosylxanthones have been isolated from 31 plant species belonging to 10 families. Mangiferin (1) was the most reported one and the most biologically screened. Antioxidant activity was the most performed test on isolated compounds, while some strong and good anti-inflammatory, antiplasmodial, and α-glucosidase inhibitory activities have been also reported in the literature for some C-glycosylxanthones. This paper is a mini-review summarizing the occurrence, chemistry, and biological activities of C-glycosylxanthones. The writing of this paper has been done using the literature collected from online libraries including SciFinder, PubMed, Web of Science, and Google Scholar using keywords xanthone, glycosyl, C-glycosylxanthone, without language restriction. This review represents therefore the easiest access to the information on C-glycosylxanthones for researchers intending to also continue the research investigations on this topic.
... To determine the in vitro α-amylase activity of the extracts, the method DineshKumar et al. [16], based on α-amylase (EC 3.2.1.1) inhibition was employed. ...
Four extracts of Chrysophyllum cainito L. were made, namely, ethanolic extract of pulp (EEPC), ethanolic extract of peel (EECC), aqueous extract of pulp (EAPC) and aqueous extract of peel (EACC). The content of phenols and flavonoids, as well as antioxidant activity and in vitro antidiabetic activity, were determined for these extracts. EECC showed a higher content of phenolic compounds and total flavonoids compared to the pulp extracts, specifically 5.16 ± 0.13 g.kg-1 (expressed as gallic acid equivalents) and 4.71 ± 0.18 g.kg-1 (expressed as catechin equivalents), respectively. Regarding the antioxidant activity, EECC free radical scavenging of 78.8 ± 0.1 % was determined by the 2,2-diphenyl-1-picrilhidrazyl (DPPH) assay and 80.3 ± 0.1 % by the 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay. EECC had the highest inhibition index on the digestive enzyme alpha-amylase (87.7 ± 8.3 %). The Chrysophyllum cainito fruit was found to possess a free radical donor capacity and inhibitory activity of amylolytic enzyme, important in control of diabetes mellitus and its complications.
... To determine the in vitro α-amylase activity of the extracts, the method DineshKumar et al. [16], based on α-amylase (EC 3.2.1.1) inhibition was employed. ...
Four extracts of Chrysophyllum cainito L. were made, namely, ethanolic extract of pulp (EEPC), ethanolic extract of peel (EECC), aqueous extract of pulp (EAPC) and aqueous extract of peel (EACC). The content of phenols and flavonoids, as well as antioxidant activity and in vitro antidiabetic activity, were determined for these extracts. EECC showed a higher content of phenolic compounds and total flavonoids compared to the pulp extracts, specifically 5.16 ± 0.13 g.kg-1 (expressed as gallic acid equivalents) and 4.71 ± 0.18 g.kg-1 (expressed as catechin equivalents), respectively. Regarding the antioxidant activity, EECC free radical scavenging of 78.8 ± 0.1 % was determined by the 2,2-diphenyl-1-picrilhidrazyl (DPPH) assay and 80.3 ± 0.1 % by the 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay. EECC had the highest inhibition index on the digestive enzyme α-amylase (87.7 ± 8.3 %). The Chrysophyllum cainito fruit was found to possess a free radical donor capacity and inhibitory activity of amylolytic enzyme, important in control of diabetes mellitus and its complications.
... The amount of MG in the endocarp is reported to be higher compared to seeds; hence, MG, along with some other constituents, may be responsible for the α-amylase activity. Previous studies have confirmed the α-amylase inhibitory role of mango peel-extracted MG [34][35][36]. Furthermore, in vivo studies on mango peel extract also supported the antidiabetic potential for MG [9,34,37]. However, phenolic compounds may also play a vital role as suppressors of postprandial hyperglycemia at different concentrations [38]. ...
Mango fruit is well known for its nutritional and health benefits due to the presence of a plethora of phytochemical classes. The quality of mango fruit and its biological activities may change depending upon the variation in geographical factors. For the first time, this study comprehensively screened the biological activities of all four parts of the mango fruit from twelve different origins. Various cell lines (MCF7, HCT116, HepG2, MRC5) were used to screen the extracts for their cytotoxicity, glucose uptake, glutathione peroxidase activity, and α-amylase inhibition. MTT assays were carried out to calculate the IC50 values for the most effective extracts. The seed part from Kenya and Sri Lanka origins exhibited an IC50 value of 14.44 ± 3.61 (HCT116) and 17.19 ± 1.60 (MCF7). The seed part for Yemen Badami (119 ± 0.08) and epicarp part of Thailand (119 ± 0.11) mango fruit showed a significant increase in glucose utilization (50 μg/mL) as compared to the standard drug metformin (123 ± 0.07). The seed extracts of Yemen Taimoor seed (0.46 ± 0.05) and Yemen Badami (0.62 ± 0.13) produced a significant reduction in GPx activity (50 μg/mL) compared to the control cells (100 μg/mL). For α-amylase inhibition, the lowest IC50 value was observed for the endocarp part of Yemen Kalabathoor (108.8 ± 0.70 μg/mL). PCA, ANOVA, and Pearson’s statistical models revealed a significant correlation for the fruit part vs. biological activities, and seed part vs. cytotoxicity and α-amylase activity (p = 0.05). The seed of mango fruit exhibited significant biological activities; hence, further in-depth metabolomic and in vivo studies are essential to effectively utilize the seed part for the treatment of various diseases.
... On the other side, diabetic caused a significant decrease in HDL-C compared with the normal rats, while, treating diabetic rats with glibenclamide and aqueous mango leaves extract caused a significant increase in the levels of HDL-C compared with the diabetic rats. The highest increase was achieved by using glibenclamide with aqueous mango leaves extract followed by diabetic rats treated with aqueous mango leaves extract and diabetic rats treated with glibenclamide, these results are in harmony with those obtained by Dineshkumar et al. (30) whom found that significant reductions in lipid variables after treatment with M. indica leaves extract due to its polyphenol compound in mangiferin which may be ascribed to lipid lowering activity or due to its influence on various lipid regulation systems. ...
Xanthones are a class of secondary metabolites produced by plant organisms. They are characterized by a wide structural variety and numerous biological activities that make them valuable metabolites for use in the pharmaceutical field. This review shows the current knowledge of the xanthone biosynthetic pathway with a focus on the precursors and the enzymes involved, as well as on the cellular and organ localization of xanthones in plants. Xanthone biosynthesis in plants involves the shikimate and the acetate pathways which originate in plastids and endoplasmic reticulum, respectively. The pathway continues following three alternative routes, two phenylalanine-dependent and one phenylalanine-independent. All three routes lead to the biosynthesis of 2,3′,4,6-tetrahydroxybenzophenone, which is the central intermediate. Unlike plants, the xanthone core in fungi and lichens is wholly derived from polyketide. Although organs and tissues synthesizing and accumulating xanthones are known in plants, no information is yet available on their subcellular and cellular localization in fungi and lichens. This review highlights the studies published to date on xanthone biosynthesis and trafficking in plant organisms, from which it emerges that the mechanisms underlying their synthesis need to be further investigated in order to exploit them for application purposes.
Many medicinal plants have been used for the treatment of diabetes mellitus in Indian system of medicine and in other ancient systems of the world. Medicinal plants are significant source of biological compounds and many of the currently available biological compounds have been derived directly or indirectly from them. The major focus of this review is on anti-diabetic activity of medicinal plants like Achillea ligutica, Aegles marmelos, Andrographis paniculata, Azadirachta indica, Allium sativum, Bergenia ciliata, Brassica juncea, Commelina communis, Euonymus alatus, Ficus bengalensis, Gymnema sylvestre, Mangifera indica, Medicago sativa, Momordica charantia, Murraya koenigii, Pterocarpus marsupium, Syzigium cumini, Trigonella foenum graecum, Tinospora cripa, Tournefortia haetwegiana (active constituents and crude extracts). These medicinal plants act on various mechanisms-either by acting directly on pancreas and stimulate insulin levels in blood or by altering the activities of regulatory enzymes in different pathways like glycolysis, gluconeogensis and thus producing effects on tissues like liver, muscle, adipose tissue etc. All medicinal plants, as specified, have shown different degrees of anti-diabetic activity.
Objective—To assess the roles of plasma triglyceride and high density lipoprotein (HDL) cholesterol concentrations in predicting ischaemic heart disease.Design—Two prospective cohort studies with common core protocols.Setting and participants—Both cohorts are 100% samples of middle aged men. In Caerphilly the 2512 men were living within a defined area. In Speedwell the 2348 men were registered with local general practitioners.Main outcome measures—Fasting blood samples were taken at initial examination and plasma lipid concentrations were measured. Major ischaemic heart disease events were assessed from hospital notes, death certificates, and electrocardiograms.Results—At first follow up, after an average of 5·1 years in Caerphilly and 3·2 years in Speedwell, 251 major ischaemic heart disease events had occurred. Men with triglyceride concentrations in the top 20% of the distribution had a relative odds value for ischaemic heart disease of 2·3 (95% confidence interval (95% CI) 1·3 to 4·1) compared with men in the bottom 20%, after adjusting for both plasma total and HDL cholesterol, and non-lipid risk factors. Men in the lowest 20% of the distribution of HDL cholesterol concentration had a relative odds value of 1·7 (95% CI 1·0 to 2·8) compared with the top 20%, after adjustment was made for total cholesterol and triglyceride concentrations, and non-lipid risk factors. These relations were not caused by β blockers, which were being taken by 5% of the men.Conclusions—Plasma triglyceride concentration predicts major ischaemic events after allowance is made for total and HDL cholesterol concentrations and other risk factors. In these populations, triglyceride is a more important predictor than total cholesterol concentration.
Traditional treatment applies different herbal principles used as a composite in food, serving as an effective measure against different diseases like diabetes in economically backward rural India lacking in health service infrastructure. The present study intends to observe the effects of a composite of Tulsi (Ocimum Sanctum) leaves, Amla (Emblica Officinalis), Bitter Gourd (Momordica Charantia), Gurmur (Gymnema sylvestre) leaves and Jamun (Syzygium Cumini) fruit and its seed, on mild diabetic patients. 120 patients whose Fasting Blood Sugar values is below 180mg/dl and without any complications of diabetes, and free from other diseases, are screened out of 2607 cases from hospitals at and around Kharagpur by random selection (lottery), divided into two groups of 60 patients each (lottery). The experimental group receives the composite of the above substances mixed with Soybean Sattu and used as a breakfast item for three months. The parameters like fasting blood sugar and lipid profile values for both experimental and control groups are measured at monthly intervals and compared statistically. Insulin resistance pictures are calculated. Application of the composite results in reduction of fasting blood sugar, bad cholesterols and Insulin resistance and increase in good cholesterol. Normal distribution method is used to analyse the data. The composite in this study causes beneficial changes in the blood bio-chemic parameters with reduction of Insulin resistance in the patients and needs to be supported by long-term experimentations.
This review attempts to portray the discovery and de-velopment of medicine from galenical to genomical, with a focus on the potential and role of ayurveda. Natural products, including plants, animals and min-erals have been the basis of treatment of human dis-eases. Indigenous people derived therapeutic materials from thousands of plants; however discovering medi-cines or poisons remains a vital question. Ayurveda is a traditional Indian medicinal system being practised for thousands of years. Considerable research on pharmacognosy, chemistry, pharmacology and clinical therapeutics has been carried out on ayurvedic medi-cinal plants. Many of the major pharmaceutical cor-porations have renewed their strategies in favour of natural products drug discovery and it is important to follow systems biology applications to facilitate the process. Numerous drugs have entered the interna-tional pharmacopoeia through the study of ethno-pharmacology and traditional medicine. For ayurveda and other traditional medicines newer guidelines of standardization, manufacture and quality control are required. Employing a unique holistic approach, ayur-vedic medicines are usually customized to an indivi-dual constitution. Traditional knowledge-driven drug development can follow a reverse pharmacology path and reduce time and cost of development. New appro-aches to improve and accelerate the joint drug discov-ery and development process are expected to take place mainly from innovation in drug target elucida-tion and lead structure discovery. Powerful new tech-nologies such as automated separation techniques, high-throughput screening and combinatorial chemis-try are revolutionizing drug discovery. Traditional knowledge will serve as a powerful search engine and most importantly, will greatly facilitate intentional, focused and safe natural products research to redis-cover the drug discovery process.
Mangiferin, C19H18O11, has been isolated from the leaves, heartwood and stem-bark of Mangifera indica. Its properties indicate that it is a stable C-glycoside of the xanthone group. Reductive hydrolysis with hydriodic acid and oxidation with ferric chloride yield 1,3,6,7-tetrahydroxyxanthone and glucose respectively indicating that it is a glucoside of the former and oxidation with periodic acid reveals that the sugar is in the pyranose form. The position of linkage has been shown to be 2 by oxidizing mangiferin tri and tetra methyl ethers with periodate to the corresponding α-hydroxyacetaldehydes of trimethoxy and tetramethoxyxanthones and comparing them with synthetic samples obtained from the appropriate 2-allylxanthones. This has been further supported by oxidation of mangiferin tetra methyl ether and 2-allyl-1,3,6,7-tetramethoxyxanthone with permanganate yielding 1,3,6,7-tetramethoxyxanthone-2-carboxylic acid.
The mangos' popularity is on the rise due to its high nutraceutic and pharmaceutical value. The mango is unique because each of its parts—fruit, pulp, peel, seed, leaves, flowers and the bark—are utilizable. Polyphenolic compounds and related bioactivity in the fruit are higher in peel than pulp and highest in mango leaves and stem barks. There are various polyphenols in mango, but Mangiferin, is abundant and bioactive. Synergy among various polyphenols and mocro-elements in mango extracts is responsible for their high bioactivity as compared to pure isolated compounds and explains their use in the management of various degenerative diseases.
A roselle (Hibiscus sabdariffa Linn.) tea extract was found to have high inhibitory activity against porcine pancreatic or-amylase. Hibiscus acid and its 6-methyl ester were respectively isolated as active principles from the 50% methanol and acetone extracts of roselle tea. The activity of each isolate was compared to that of structurally related citric acid, a previously known inhibitor of fungal alpha-amylase.
Here we present a one-pot procedure for the synthesis of a library of carbohydrate compounds belonging to four classes of glycosidase inhibitors: glycosides, aldonic acid lactams, aldonic acid lactones and dideoxy-iminoalditols. The complex mixture was separated into individual components that were screened for activity against α- and β-glucosidases. Among these were two 2-O-methyl glycosides that reduced the rate of the enzymatically-catalyzed hydrolysis of the p-nitrophenyl glucosides used in the assay. Relative inhibition indices normalized to the inhibition observed with deoxynojirimycin under similar conditions were determined. This methodology provides a straightforward, general and time-efficient way to synthesize, test and analyze an extensive number of glycosidase inhibitor candidates from several carbohydrate compound classes in one scheme. The direct reference to deoxynojirimycin gives an immediate indication of the concentration range in which a significant inhibitory activity can be obtained.
T he epidemic of type 2 diabetes in the United States and the rest of the world continues to grow rapidly; as many as 20 million people in the United States may have the disease.1 The vast majority of people with diabetes have type 2 diabetes, caused by a relative insulin deficiency superimposed on a background of insulin resistance.2 Most patients begin treatment with diet and exercise or incorporate them into their treatment regimen, but, unfortunately, most patients are unsuccessful in controlling type 2 diabetes through lifestyle modification alone and require pharmacotherapy.
For several reasons, oral agents are typically the first medications used in the treatment of type 2 diabetes. Because of their wide range of efficacy, safety, and mechanisms of action, it is important for clinicians to gain a broad understanding of each class of oral agents to optimize diabetes control. This article reviews the major classes of oral agents used to treat type 2 diabetes, with an emphasis on the benefits and risks of each class. It is important to note that because type 1 diabetes results from an absolute deficiency of pancreatic β-cells, most oral agents are not indicated in the treatment of patients with type 1 diabetes. Oral agents are also largely not tested or approved for use in pregnancy.
Metformin is the sole member of the biguanide class of medications in the United States. It replaced another biguanide, fenformin, which was removed from the market because of a propensity for lactic acidosis in 1975.3,4 Available in short-acting and sustained-release formulations, it is one of the oldest, and indeed one of the safest, medications used in the treatment of type 2 diabetes.
Metformin exerts its effects primarily by decreasing hepatic glucose output and has a comparatively lesser effect increasing insulin sensitivity. …