• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.4
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• pp.418-422
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• 1993

For the purpose of utilizing tannins in the functional foods and crude drugs the xanthine oxidase inhibition of tannins isolated from Korean green tea was determined. Acetone extract from Korean green tea showed inhibitory effect against the xanthine oxidase. The galloyl tannins showed higher inhibitory activity against xanthine oxidase than the nongalloyl tannins. In terms of stereo isomers, (-)-epicatechins had higher inhibitory activity than the (+)-catechins. The synergistic activity was also observed. Tannins isolated from Korean green tea appeared to be incompetitive inhibitor against the xanthine oxidase.

• Advances in Traditional Medicine
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• v.8 no.2
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• pp.171-177
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• 2008

Epigallocatechin 3-gallate (EGCG), one of the major catechins of tea, was isolated from the decaffeinated, crude methanolic extract of Indian green tea (Camellia sinensis L. O. Kuntze) using chromatographic techniques. EGCG was then screened for antidiarrhoeal activity against 30 strains (clinical isolates) of V. cholerae, which is a well known Gram negative bacillus functioning as the pathogen of cholera. V. cholerae strains like V. cholerae 69, 71, 83, 214, 978, 1021, 1315, 1347, 1348, 569B and ATCC 14033 were inhibited by EGCG at a concentration of $25\;{\mu}g/ml$ whereas V. cholerae 10, 522, 976 were even more sensitive, being inhibited at $10\;{\mu}g/ml$ level. However, V. cholerae DN 16, DN 26, 30, 42, 56, 58, 113, 117, 564, 593, 972 and ATCC 14035 were inhibited at $50\;{\mu}g/ml$ level of EGCG. Only four strains were inhibited at $100\;{\mu}g/ml$. In this study the isolated compound was found to be bacteriostatic in its mechanism of action. In the in vivo experiment using the rabbit ileal loop model two different dosages of EGCG ($500\;{\mu}g/ml$ and $1,000\;{\mu}g/ml$) were able to protect the animals when they were challenged with V. cholerae 569B in the ileum.

• Korean Journal of Food Science and Technology
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• v.25 no.3
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• pp.238-242
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• 1993

For the Purpose of utilizing tannins in the functional foods and crude drugs, the enzyme inhibition of tannins isolated from Korean green tea were determined. Acetone extract from Korean green tea showed inhibition effect against the angiotensin converting enzyme. The galloyl tannins showed higher inhibition activity against angioteosin converting enzyme than the nongalloyl tannins. In terms of stereo isomers, (-)-epicatechins had higher inhibition activity than the (+ )-catechins. The synergistic activity was also observed. Tannins isolated from Korean green tea appeared to be incompetitive inhibitor against the angiotensin converting enzyme.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.1
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• pp.160-168
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• 1995

Desmutagenicities against 2-amino-1-methyl-6-phenylimidazo[4, 5-b] pyridine(PhIP) and 2-amino-3, 8-dimethylimidazo[4, 5-f]quinoxaline(MelQx) of tea extracts (steamed green tea, roasted green tea, oolong tea and black tea) were investigated. All the fractions obtained from tea extracts showed strong desmutagenic activity against PhIP and MeIQx toward S. typhimurium TA 98 in the presence of the S-9 mix. The crude catechin fraction exhibited the strongest desmutagenic activity. Among these tea extracts, black tea especially exhibited the strongest desmutagenic activity and the activity was 70.9~91.0% against PhIP and 92.2~98.8% against MelQx at a concentration(0.5~1.0mg/plate) for drinking. The activity of authentic catechins of (-)-EGC, (-)-EGCg, (-)-ECg and (-)-EC were 79.5%, 60.2%, 46.1% and 43.5% against PhIP, and were 52.3%, 11.6%, 8.2% and 22.1% against MelQx by addition of 1.0mg/plate, respectively. The desmutagenic activity was supposedly due to the (-)-EGCg, (-)-EGC and (-)-EC in tea polyphenols, and the browning materials. The desmutagenicity was stronger when mutagens were preincubated with S-9 mix after reaciton with black tea extracts than when preincubated with them after reaction with S-9 mix. The desmutagenicity of tea extracts was rather expressed by reacting directly with mutagens than by deactivating the activated forms of mutagens.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.9
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• pp.1369-1379
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• 2014

The physicochemical characteristics and antioxidant activities of leaf, stem, and root of ginger (Zingiber officinale R.) were determined. Nutrient composition, reducing sugar, saponin, mineral, heavy metal, total phenolic and total flavonoid contents, and antioxidant activities based on DPPH radical scavenging and FRAP assay were measured. Catechins, gingerols, shogaols, and capsaicin compositions were also determined by HPLC. The contents of water, proteins, fats, carbohydrates, fiber, and ash from ginger root were 6.4, 6.8, 3.2, 65.4, 7.3, and 18.2%, respectively. Crude fiber contents of leaf and stem were 4~5 times higher than those of root (P<0.05), and reducing sugar content of stem was about 3 times higher than those of root. Crude saponin contents were in the order of stem