Fig 5 - uploaded by Dr. Saqib Jabbar
Content may be subject to copyright.
Diagram of separation of tea polyphenols, theanine and caffeine from summer green tea by column chromatography.
Source publication
In the present study, feasibility of producing high quality of tea polyphenols, theanine
and caffeine from the extract of summer green tea by column chromatography was investigated.
Crude extract of summer green tea obtained by hot water extraction was passed through columns of
polyamide and NKA-II macroporous resin respectively, resulting in te...
Context in source publication
Context 1
... by pure water, the column was eluted by 80% ethanol and the elution from 2.5 th BV to 5 th BV (fraction 3) was collected. The fractions 1-3 which were rich in tea polyphenols, theanine and caffeine, respectively, were concentrated under vacuum in a rotary evaporator and lyophilized, affording the products of tea polyphenols, theanine and caffeine (Fig. 6). The purities of resulting tea polyphenols, theanine and caffeine were 96.27 ± 1.78%, 99.02 ± 0.43% and 99.25 ± 0.36%, ...
Similar publications
To determine differences in quality parameters between different types of tea elaborated in Argentina, water extract, crude fibre, caffeine, total polyphenol content, antioxidant activity, sorption isotherms and colour parameters (L, a, b) were determined. Fifty-one industrial samples of commercially available teas including green tea, semifermente...
Citations
... Milk thistle seeds were ground to fine powder by grinder (MJ-M176P, Panasonic, Japan) followed by the method described of Zhang et al. (2013). Briefly, a 5 g sample of milk thistle seed powder was extracted with the 100 mL of 80% ethanol solution for 60 min at 70 °C in a shaking water bath. ...
The current study was designed to measure phenolics and antioxidant properties of milk thistle seeds on optimal processing conditions. The optimized conditions (time (60 min), temperature (70 °C), solvent (ethanol 80%), and liquid solid ratio (1:10)) showed a better correlation between the hypothesized and experimental values. The results revealed that the flavonolignans purified by dynamic state (2BV) with the most favorable state for the separation of impurities and high contents of polyphenols. Silymarin (SMR) is the major compound with a molecular weight was 481 m/z present in milk thistle that was identified by optimized HPLC condition and characterized by ESI–MS/MS. The active fractions were isolated by ÄKTA purifier with 40% methanol. Furthermore, each compound had a high antioxidant capacity on RAW 264.7 cells. But the % 2,2-diphenyl-1-picrylhydrazyl activity was found to be higher in SMR than other components. Hence, Taxifolin is the most effective com-pound of SMR due to free radical and hydroxyl radical antioxidant capacity. The SCN and SDN also showed effect as a total antioxidant activity rather than SBN and ISBN.
... Simultaneous preparation would contribute to the comprehensive utilization of the tea bioactive compounds and cost reduction. Polyphenols, theanine and caffeine could be simultaneously achieved from green tea extract at purities of 96.27% (recovery rate 72.42%), 99.02% (recovery rate 66.12%) and 99.25% (recovery rate 62.07%), respectively, through separation with a polyamide column and a macro-porous resin NKA-II column [48]. However, a complex elution program and a large elution volume were used, which made it impossible to apply in large-scale production. ...
Adsorption is an important technology for the separation of different tea components. The adsorption behavior of L-theanine onto adsorbents was comprehensively studied in this paper. Among tested adsorbents, cation exchange resin ZGSPC106Na and D001SD were suitable for separating L-theanine, PVPP and PA-6 for catechins and macroporous resin HPD-400 for caffeine. Adsorption of L-theanine onto the cation resins was significantly influenced by the acidity, contact time and temperature. The adsorption behavior could be described by the pseudo-second-order rate equation and fitted to Langmuir and Freundlich models. ZGSPC106Na exhibited higher adsorption capacity, while D001SD showed higher adsorption selectivity. These might be attributed to the distinctive structure of the two resins and different ionization of the adsorbates. A method for simultaneous preparation of decaffeinated polyphenols, caffeine-enriched extract and decaffeinated L-theanine was established through successive separation on the columns fulfilled with PA-6, HPD-400 and D001SD, respectively.
... Other methods involve fractionation of a green tea extract by selective precipitation of catechins with a precipitation agent [21] and different adsorption separation processes. Several adsorbents have been tested, such as lignocellulose [22,23] and lignocellulose copolymerized with N-vinylpyrrolidone [24], activated carbon [25], polyvinylpolypyrrolidone [26,27], polyamide [28], poly(acrylamide-co-ethylene glycol dimethacrylate) [29] and different macroporous polymeric resins [30,31]. ...
... Other methods involve fractionation of a green tea extract by selective precipitation of catechins with a precipitation agent [21] and different adsorption separation processes. Several adsorbents have been tested, such as lignocellulose [22,23] and lignocellulose copolymerized with N-vinylpyrrolidone [24], activated carbon [25], polyvinylpolypyrrolidone [26,27], polyamide [28], poly(acrylamide-co-ethylene glycol dimethacrylate) [29] and different macroporous polymeric resins [30,31]. ...
This paper reports a method to produce a solvent-free extract from green tea leaves with high content of catechins and low content of caffeine, in two steps and using only "green" solvents. The method is based on the pressurized liquid extraction (PLE) of the green tea leaves using ethyl lactate as solvent, followed by a selective precipitation procedure using the supercritical carbon dioxide (SCCO2) antisolvent (SAS) technique. PLE was accomplished at 100°C and 10 MPa, on the basis of a previous work. The influence of pressure (15-30 MPa) and temperature (50°C and 70°C) on the SAS precipitation process was experimentally studied in terms of precipitation yield, concentration of key bioactive compounds (caffeine and monomeric catechins) and total content of phenols of the precipitates. Additionally, a comparison using a different organic solvent (ethanol) for the extraction and precipitation steps is reported. The precipitates obtained from the ethyl lactate PLE extracts were decaffeinated (giving less than 1% mass caffeine in the dry matter) and the concentration of catechins was close to 23% mass. The total phenolic content of the precipitates was up to 590 mg of gallic acid equivalents per g of precipitate, which represents an increase of up to 25% with respect to the PLE extracts.
Tea polyphenols are claimed to have many health benefits. The fact that tea is such a popular drink, together with all the potential health benefits, has led to an increased interest in the recovery and purification of the polyphenols. The most interesting groups of polyphenols present in black tea are the catechins and the theaflavins. To the best of the authors' knowledge, no report on a systematic resin screening study for the adsorption and desorption of specific polyphenols from black tea has been presented. Four food grade commercial macroporous resins are screened as a starting point for the characterization and optimization of a solvent swing adsorption process, to separate the polyphenols from black tea. It has been shown that the resin Amberlite XAD7HP has the best performance for the sorption of catechins, allowing the recovery of 60% of the catechins. The resin Amberlite FPX66 is the best for sorption of theaflavins, with a recovery rate of 59%. The adsorption process has been modeled with a Langmuir multicomponent isotherm. In desorption, a solution containing 70% ethanol (weight percent) in water is found to be the best desorption medium.
In order to investigate the inhibitory effects and possible mechanisms of Oolong tea polyphenols, (-)-epigallocatechin gallate (EGCG) and (-)-epigallocatechin 3-O-(3-O-methyl) gallate (EGCG3"Me) on pancreatic -amylase, the inhibition, enzyme kinetics, ultraviolet (UV) absorption spectrum and fluorescence spectrum of -amylase were investigated. The results showed that Oolong tea polyphenols, EGCG and EGCG3"Me all exhibited inhibitory effects against -amylase, and their half inhibitory concentration (IC50) values were 0.375, 0.350 and 0.572 mg/mL, respectively. The results of Lineweaver-Burk double reciprocal plot indicated that the inhibitory types of Oolong tea polyphenols and EGCG were competitive, whereas EGCG3"Me was in a noncompetitive pattern. Oolong tea polyphenols, EGCG and EGCG3"Me all induced red-shift of UV absorbance and quenching of fluorescence of -amylase, suggesting possible changes in the conformation of -amylase. The differences of inhibitory effects and inhibition types for EGCG and EGCG3"Me might be due to their structural difference (the hydroxyl group at C-3 in D ring of EGCG substituted by methoxy group, forming EGCG3"Me).
