• Nutritional Sciences
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• v.8 no.3
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• pp.175-180
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• 2005

Green tea, which has high polyphenols amount, is thought to have hypocholesterolemic effects. The present study was performed to further examine the hypocholesterolemic action of green tea, especially (-) epigallocatechin gallate (EGCG) for its effect on diet-induced hypercholesterolemia in rats. Male Sprague-Dawley rats (n=15) were fed a green tea-free diet (control), $1.0\%$ green tea catechin (catechin) or $0.5\%$ green tea catechin EGCG for seven weeks. Hypercholesterolemia was induced by adding $1\%$ cholesterol and $0.5\%$ cholic acid to all diets. There was no difference in food intake and body weight gain among the groups. The green tea EGCG treatment led to a significant improvement in plasma levels of total cholesterol, low density lipoprotein (LDL)-cholesterol and high density lipoprotein (HDL)/LDL ratio (p<0.05). There was no significant effect on the plasma HDL-cholesterol level. The catechin treatment led to a 4.19-fold increase in the LDL-receptor mRNA level compared to the control, but the EGCG treatment did not affect the hepatic LDL-receptor mRNA level. Our results suggest that when blood cholesterol level is down-regulated by green tea EGCG, the LDL receptor gene-independent pathway may dominate the hypocholesterolemic action of EGCG.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.1
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• pp.47-51
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• 2004

Green tea, which is high in polyphenols, is thought to have hypocholesterolemic effects. The present study was performed to further elucidate the hypocholesterolemic actions of green tea, specially the catechin and (-)-epigallocatechin gallate (EGCG) for their effects on the diet-induced hypercholesterolemia in rats. Male Sprague-Dawley rats were fed with green tea-free diet (control), diets containing 4% green tea powder (GTP), 1.0% green tea catechin (catechin) or 0.5% epigallocatechin gallate (EGCG) for 7 wks. All diets that were provided green tea contained approximately 0.5% EGCG Hypercholesterolemia was induced by adding 1% cholesterol and 0.5% cholic acid to all diets. There were no differences in food intake among groups. The green tea treatments showed significant improvement in the serum levels of total cholesterol, LDL-cholesterol, triacylglycerides and atherogenic index in the following order; EGCG>Catechin>GTP (p<0.05). The serum HDL-cholesterol level was highest in the EGCG-treated group. The catechin or EGCG diet up-regulated by 5 times the enzyme activity of hepatic cholesterol 7$\alpha$ -hydroxylase (CYP7Al) compared to control diet (p<0.05). Hepatic CYP7Al mRNA level paralleled tile increases in the CYP7Al activity. These results suggest that the EGCG in the green tea may account for the hypocholesterolemic effect by the induction of CYP7Al gene expression.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.4
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• pp.386-389
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• 1992

The four main tea catechin components (-)-epicatechin (EC), (-)-epigallocatechin (EGC) , (-)-epicatechin gallate (ECg), and (-)-epigallocatechin gallate (EGCg) were analyzed quantitatively from commerical green teas by HPLC. CATechin of the most amounts in steamed and parched teas was EGcg (steamed 1st : 7.54% , parched 1st : 7.88%). Amounts of catechins decreased in the following order : EGCg > EGC>ECg>EC. Almost same tendency of catechin components change of 1st tea and 2nd tea differed to harvesting time being observed in steamed and parched teas. In 2nd tea, amounts of EGCg increased more than in 1st tea. It seems that this change effects on the quality of tea taste.

• Journal of Food Hygiene and Safety
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• v.17 no.3
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• pp.117-123
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• 2002

The five main green tea catechin components such as (+)-catechin, (-)-epicatechin, (-)-epigallocatechin, (-)-epicatechin gallate, and (-)-epigallocatechin gallate were analyzed quantitatively from commercial green tea by HPLC. Amounts of catechins decreased in the following order : (+)-catechin > (-)-epigallocatechin gallate >(-)-epigallocatechin >(-)-epicatechin >(-)-epicatechin gallate. In this study, the stability of the following green tea catechins to pH in the range from 3 to 11 was studied using of ultraviolet spectroscopy : (+)-catechin, (-)-epicatechin, (-)-epicatechin gallate, and (-)-epigallocatechin gallate. This study demonstrated that green tea catechins were not stable at high pH and that the pH-, and time-dependent spectral alternatives were not reversible In conclusion, low pH is important to maintain the efficient utilization of green tea catechins.

• KSBB Journal
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• v.16 no.5
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• pp.442-445
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• 2001

Catechin compounds as anticancer and antioxidant were target materials from Korean Green Tea in this work. The methodologies of solvent extraction and partition were utilized to recover catechin compounds from green tea and the optimal experimental conditions were found by comparing the degree of recovery as slovent. extraction times and operating temperatures. The extract was partitioned with chloroform, which was best fit to remove caffeine after the extraction of green tea with 80$^{\circ}C$ water for 40 min. Further, the resulting extract was partitioned in ethyl acetate layer to purify the catechin compounds of EGC, EC EGCG and ECG. This experimental result could be extended to preparative HPLC to obtain EGCG on a commercial scale.

• KSBB Journal
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• v.14 no.5
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• pp.517-522
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• 1999

A green tea used in this experiment was cultivated at Bosung (Chonnam) and purchased from a domestic market. The extract at 5$0^{\circ}C$ water from the powder of green tea partitioned with chloroform and ethyl acetate. The resulting solution was further purified with a chromatographic column (4.6$\times$250 mm, 15${\mu}{\textrm}{m}$, Lichrospher 100RP-18). Finally separation was achieved on a $\mu$-Bondapak $C_18$(3.9$\times$300mm, 10${\mu}{\textrm}{m}$) column. The elution order of the catechin compounds contained in the green tea was EGC(Epigallocatechin, C(catechin), EC(Epicatechin), EGCG(Epigallocatechin Gallate) and ECG(Epicatechin Gallate). From the experimental results the mobile phase for isolating EGCG from the extract consisted of 0.1% acetic acid in water/acetonitrile, 87/13%(v/v). The flow rate of mobile phase was 1.0 $m\ell$/min, and UV wavelength was fixed at 280 nm. 121.3 mg of EGCG, higher than 98% of purity, was obtained from 5 g of dry green tea.

• Food Science and Biotechnology
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• v.16 no.1
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• pp.167-170
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• 2007

(-)-Epigallocatechin-3-gallate (EGCG), a mai or tea catechin has been shown to have many interesting biological activities. In the present study, we studied the effects of green tea catechins, EGCG metabolites, and black tea theaflavins on accumulation of EGCG in HT-29 human colon cells. Intracellular levels of [$^3H$]-EGCG were not changed significantly in the presence of other tea catechins including (-)-epicatechin, (-)-epigallocatechin, and (-)-epicatechin-3-gallate. EGCG methyl metabolites and EGCG 4"-glucuronide did not affect cellular levels of [$^3H$]-EGCG. Black tea theaflavins and theasinensin A (TsA), an EGCG oxidative dimer, however, significantly decreased cellular accumulation of EGCG in HT-29 cells by 31-56%. This decrease was more pronounced when cells were incubated in the presence of theaflavin-3',3"-digallate (TFdiG) or TsA. When EGCG was added separately from TFdiG or TsA, the accumulation of EGCG in HT-29 cells was also significantly decreased regardless of when TFdiG or TsA was added during the uptake study (p<0.01). The results suggest that theaflavins and TsA may interrupt EGCG absorption through the gastrointestinal epithelium.

• The Journal of the Korea Contents Association
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• v.12 no.11
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• pp.278-285
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• 2012

In an experiment in which fermentation was done by adding fungal species that have antibiosis but do not have cellulase, the extraction amount of EGC, EC, EGCG, and ECG increased in all samples that fermented by adding sun-dried salt compared to those that fermented only with green tea after fermenting green tea by mixing it with sun-dried salt. In the analysis conducted according to the days of fermentation, the high extraction amounts of EGC(epigallocatechin), ECG(epicatechin gallate), EC(epicatechin), and EGCG(epigallocatechin gallate) were detected on the second and third day. Furthermore, when fermentation was done by adding ferment bacillus, all types of catechin(EGC, EC, EGCG, ECG) extraction increased in Paenibacillus spp but in Bacillus amyloliquefaciens, EGC and EC decreased while EGCG and ECG increased; whereas in Bacillus pumilus and Bacillus subtilis all types of catechin(EGC, EC, EGCG, ECG) decreased. The results of the above experiment reveal that the largest amount of catechin was extracted from the result which conducted fermentation for three days together with sun-dried salt and Paenibacillus spp in the green tea.

• Journal of Nutrition and Health
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• v.35 no.1
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• pp.53-59
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• 2002

Green tea has been recognized as a favorite beverage for centuries in Easter and Westers cultures. Recently, anti-tumor effects of green tea constituents have received increasing attention. However, the mechanism of catechin-mediated cytotoxicity against tumor cells remains to be elusive. To elucidate the mechanical insights of anti-tumor effects, (-)epigallocatechin-gallate(EGCG) of catechin was applied to human lung cancer A549 cells. (-)EGCG induced the death of A549 cells, which was revealed as apoptosis in DNA fragmentation assay. (-)EGCG induced the activation of caspase family cysteine proteases including capase-3, -8 and -9 proteases in A549 cells. Furthermore, (-)EGCG increased the phosphotransferase activity of c-Jun N-terminal kinase 1JNK 1), which further induced tole transcriptional activation of activating protein-1(AP-1) in A549 cells. We suggest that (-)EGCG-induced apotosis of A549 cells is mediated by signaling pathway involving caspase family cysteine protease, JNK1 and transcription factor, AP-1.

• Korean Journal of Plant Resources
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• v.20 no.1
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• pp.38-42
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• 2007

The present study was conducted to investigate the translocation of polyphenols, especially catechin derivatives, from mushroom medium mixed with green tea residues into fruiting body of Pleurotus eryngii. Pleurotus eryngii was grown on the media incorporated by mixing or surface-treated with dry materials including leaf petioles and young stems or leaves of green tea. The dry materials treated in medium did not affect plant height and fresh weight of Pleurotus eryngii body. From the samples of Pleurotus eryngii, the eight main catechin derivatives (-)-gallocatechin(GC), (+)-catechin (C), (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epigallocatechin gallate (EGCG), (-)-gallocatechin gallate (GCG), (-)-epicatechin gallate (ECG), and (-)-catechin gallate (EGCG), and caffeine were analyzed quantitatively by HPLC. The results showed that EGC in Pleurotus eryngii was 45% more detected, when incorporated with the dry materials, than untreated control. Especially, content of EGCG was increased in surface-treated Pleurotus eryngii up to 3.2 ppm, while it was not detected or reduced in control and other treatments. Caffeine content was greatly increased regardless of treatment method, compared with control (0.1ppm), showing 44 fold-amount in Pleurotus eryngii at early growth stage when incorporated with the dry materials into medium. The results indicates that functional catechin derivatives of green tea would be partly translocated into Pleurotus eryngii throught incorporation and surface treatment with residues of green tea plants.