• Journal of the Korean Home Economics Association
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• v.46 no.3
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• pp.49-55
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• 2008

The purpose of this study was to investigate the effects of green tea extracts (GTE) on the fermentation properties of polyphenol-enriched beers. As such, the formation patterns of tannoid in beer with GTE were investigated at 3 different infusion times, while the ale and the lager beers fortified with GTE were analyze to ascertain effects on gravity, pH, yeast viability, total polyphenol, and tannoid during fermentation period. The results were as follows: 1) The formation of tannoid in beer with GTE in the tannometer; In reaction of GTE with polyvinylpyrrolidon (PVP), control lager beer peaked in the formation of tannoid at $70\;{\sim}\;80\;mg$ of PVP, the 1st extract exceeded the detection limit, the 2nd extract at $170\;{\sim}\;180\;mg$, while the third extract at $150\;{\sim}\;160\;mg$ of PVP. The GTE were slow in reacting with PVP, and their formation patterns were different from those of polyphenols from barley and hop. 2) Ale fermentation; The final alcohol content was 9.25% (ABV). The addition of GTE increased the yeast viability after 2 days and finally reached 52.3% from 30.9%. Total polyphenol in GTE beer increased by 1.5 times (p < .05). However, its tannoid contents increased by 6.4 times. 3) Lager fermentation; The final alcohol content was 5.93% (ABV). The effect of GTE on lager beer was minimal for all variables. However, total polyphenol of GTE beer increased by 1.4 times (p < .05). Its tannoid increased by 3.3 times (p < .05).

• Applied Biological Chemistry
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• v.50 no.3
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• pp.210-216
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• 2007

Cosmetic products including skin and essence were manufactured to analyze the effect of green tea polyphenols addition. In addition, irradiation was applied to remove an undesirable color of green tea polyphenol(GTP), which may cause a problem in the marketing, of a final product; moreover, comparative studies were conducted with the cosmetic products on whether or not antiseptics were treated to verify its use for the development of non-antiseptic cosmetic products. Growth inhibition zones were shown in the microbial study except for Candida albicans. The minimum inhibitory concentration(MIC) of E. coli and C. albicans was 2,500 ppm but that of S. aureus was 1,000 ppm. The numbers of E. coli and S. aureus were reduced to undetected levels when 10,000 and 5,000 ppm of polyphenol were added, respectively. Results indicate that the addition of irradiated green tea polyphenol provides a good method to manufacture functional cosmetics including skin and essence with various biological activities such as antimicrobial activity without antiseptics.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1199-1203
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• 2003

Polyphenols were isolated from Korean green tea using Sephadex LH-20 and HPLC. The isolated polyphenols were procyanidin B-4, procyanidin B-2-3,3'-digallate, prodelphinidin C-2-3,3'-di-O-digallate, (+)-catechin-3-O-rhamnose, procyandin B-5, procyanidin B-7-3-0-gallate, gallate, epiafzelechin-$(4{\beta}{\rightarrow}8)$-epiafzelechin, procyanidin B-3-3-O-rhamnose, afzelechin-$(4{\alpha}{\rightarrow}8)$-catechin, prodelphinidin B-5-3,3'-di-O-digallate and (+)-taxifolin-3-O-D-xyloside. The inhibitory effects of prodelphinidin C-2-3,3'-di-O-gallate and procyanidin B-2-3,3'-digallate $(at\;100{\mu}M)$ on angiotensin.converting enzyme were 68.8 and 54.6%, respectively, while the inhibitory effects of prodelphinidin C-2-3,3'-di-O-gallated and procyanidin B-2-3,3'-digallate $(at\;100{\mu}m)$ on xanthine oxidase were 54.5 and 38.2%, respectively. Lastly, the inhibitory activities of prodelphinidin C-2-3,3'-di-O-gallate $(at\;100{\mu}m)$ on tyrosinase was 42.1%.

• Korean Journal of Microbiology
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• v.44 no.2
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• pp.122-129
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• 2008

The purpose of this work was to investigate the synergically bactericidal effects and cellular responses of green tea polyphenols (TPPs) and nalidixic acid (NA) on nalidixic acid-resistant (NAR) Salmonella typhimurium. The bactericidal activities of $>3,500{\mu}g/ml$ TPPs and $<256{\mu}g/ml$ NA were investigated for S. typhimurium of which initial cell number was approximately adjusted to 107 cell/ml. Complete elimination of NAS-S. typhimurium was achieved within 6 hr of incubation at the concentrations of $3,500{\mu}g/ml$ TPP or $256{\mu}g/ml$ NA, whereas only partial bactericidal effect was achieved under the same conditions. However, the combinations of $3,000{\mu}g/ml$ TPPs and $32{\mu}g/ml$ NA against NAS-S. typhimurium and $3,500{\mu}g/ml$ TPPs and $64{\mu}g/ml$ nalidixic acid against NAR-S. typhimurium showed complete removal within 5 hr of incubation. The stress shock proteins (SSPs) were induced at different concentrations of TPP o rNA used as stressors against cell culture of S. typhimurium. The proteins were identified as 70-kDa DnaK and 60-kDa GroEL by SDS-PAGE and Western blot. SSPs induced by the stressors were found to increase in proportion to the TPPs or NA. Scanning electron microscopy analyses revealed the presence of perforations and irregular rod shape with wrinkled surfaces for cells treated with TPPs or NA.

• KSBB Journal
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• v.23 no.5
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• pp.387-391
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• 2008

Green tea is popular plants in Asian countries and has become more widespread in western countries due to its taste characteristics and health benefits. Apart from green tea leafs, however, the use of root and seed of green tea tree has not intensively been investigated yet. In this study, the contents of mineral, vitamin, total amino acid, free amino acid, and total polyphenol (catechin, caffeic acid, and chlorogenic acid) of the root and seed of green tea tree were analyzed for the development of healthy foods. For minerals, potassium contents were 1,052 and 1,480 mg/100g-dry weight of root and seed, respectively. The order of mineral contents were as follows: K > P > Ca > Mg > Na > Fe > Mn > Zn > Cu in root and K > P > Na > Ca > Mg > Mn > Fe > Cu > Zn in seed. For vitamins, vitamin C contents were 5.72 and 6.05 mg/100g-dry weight of root and seed, respectively. The presence of more various kinds of vitamins were observed in seed than in root. For total amino acids, the contents were 1,651 and 4,335 mg/100g-dry weight of root and seed, respectively. The total amino acid contents of seed and root were higher than those in commercial green tea products. Especially the phenylalanine contents were 16 and 139 mg/100g-dry weight of root and seed, respectively whereas phenylalanine was not found in commercial green tea products. Concerning free amino acids, the bitter tasting amino acids such as arginine, valine and tryptophan were more abundant in root and the sweet tasting ones such as glutamic acid, alanine, aspartic acid, and serine were more abundant in seed. The total polyphenol contents were 237 and 81 mg/100g-dry weight of root and seed, respectively. The polyphenol contents in root were three times higher than that in seed so root may be a better source for antioxidant ingredients than seed. Among many polyphenols, catechin, caffeic acid, and chlorogenic acid were the top three major components.

• Journal of Life Science
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• v.27 no.4
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• pp.476-481
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• 2017

Polyphenols are secondary metabolites produced by higher plants and have been used as antiallergic, anticancer, antihypertensive, antiinflammatory, antimicrobial and antioxidant agents. They are generally divided into flavonoids and non-flavonoids. The antimicrobial activity of flavonoids are stronger than that of non-flavonoids. The skeleton structures of flavonoids possessing antimicrobial activity are chalcone, flavan-3-ol (catechin), flavanone, flavone, flavonol and proanthocyanidin. The flavonols are shown antibacterial activity against several gram-positive bacteria (Actinomyces naeslundii, Lactobacillus acidophilus and Staphylococcus aureus) and gram-negative bacteria (Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella melaninogenica and Prevotella oralis). Among of non-flavonoids, caffeic acids, ferulic acids and gallic acids showed antimicrobial activity against gram-positive (Listeria monocytogenes and S. aureus) and gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). These are found to be more efficient against the E. coli, L. monocytogenes, P. aeruginosa and S. aureus than antibiotics such as gentamicin and streptomycin. The kaempferol and quercetin showed synergistic effect with ciprofloxacin and rifampicin against S. aureus and methicillin resistant S. aureus (MRSA). Epigallocatechin gallate (EGCG) acts synergistically with various ${\beta}-lactam$ antibiotics against MRSA. In particular, the epicatechin, epigallocatechin (EGC), EGCG and gallocatechin gallate from Korean green tea has antibacterial activity against MRSA clinical isolates and the combination of tea polyphenols and oxacillin was synergistic for all the clinical MRSA isolates.

• Korean Journal of Food Science and Technology
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• v.28 no.5
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• pp.850-858
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• 1996

Green tea leaves 12.5 g were extracted twice with 500 ml boiling water. The green tea extract (GTE) contained 4.67 mg solid. The GTE contained polyphenols sush as 54.12% (-) epicatechin gallate, 26.21% (-) epicatechin, 10.71% epicatechin gallate, 7.09% (-) epicatechin and 1.85% catechin. The GTE inhibited the copper-catalyzed oxidation of human LDL at the concentrations of 50 and $100\;{\mu}g/ml$ GTE in the presence of $5\;{\mu}M$ $CuSO_{4}$. The electrophoretic mobility of the LDL oxidized in the presence of $5\;{\mu}M\;CuSO_{4}$ was higher than that of the native LDL. The GTE also inhibited LDL oxidation induced by J774, human monocyte-derived macrophages and vascular endotherial cells. The LDL modified by copper or cells was inhibited by human macrophages at a much greater rate than native LDL in the presence of GTE. The GTE was found to be a potent inhibitor of modification of LDL. GTE inhibited the uptake of cell-modified $^(125)I-labelled$ LDL by macrophages. The formation of conjugated dienes was strongly inhibited in the presence of 50 or $100\;{\mu}g/ml$ GTE.

• Journal of the Korean Society of Food Culture
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• v.19 no.2
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• pp.177-183
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• 2004

Green tea, a leaf of the plant Camellia sinensis, is one of the most consumed traditional oriental beverages. Green tea has been considered a medicine and a healthful beverage since ancient times, but recently it has received a great deal of attention because of its antioxidants like polyphenols. Moreover, green tea contains amino acids, carbohydrates, proteins, chlorophyll, volatile compounds, minerals, and phytochemical components that are essential or helpful to human health. Depending on the manufacturing process, green teas are classified into several types. Among these, powdered green tea can be effective in the absorption of ingredients compare with other types of green tea since we take the beverage with powder itself. In this paper, the contents of general ingredients (moisture, proteins, fat, carbohydrates, and ash), minerals (Fe, Mg, Ca, Na, K, and P), hunter color values, and alcohol insoluble substance were determined in total of six powdered green teas commercialized in Korea and Japan.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.527-531
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• 2003

The interest of oligomeric proanthocyanidins(OPCs) as therapeutic agents against diseases involving radical damage is growing. Proanthocyanidins are a class of polyphenolic compounds in several plant species and are oligomers of flavan-3-ol monomer units. Polyphenols in green and black tea, grape seeds, grapes and wine have raised much attention but mountain grape seed has not been investigated intensively up to now This study investigated the total OPCs contents and the total antioxidant activity of mountain grape seeds. Total antioxidant activity using DPPH method was employed and OPCs contents were determined by means of the UV-VIS spectrophotometer. The total OPCs yield of mountain grape seeds was about 1.45 % and total antioxidant activity was 15.8 ${\mu}g/m{\ell}$.

• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2222-2226
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• 2011

Amylase is a digestive enzyme that catalyses the starch into sugar. It has been reported that the green tea flavonoid (or polyphenols) (-)-epigallocatechin 3-gallate (EGCG) inhibits human salivary ${\alpha}$-amylase (HSA) and induced anti-nutritional effects. In this study, we performed docking study for seven EGCG-like flavonoids and HSA to understand the interaction mechanism of HSA and EGCG and suggest new possible flavonoid inhibitors of HSA. As a result, EGCG and (-)-epicatechin gallate (ECG) bind to HSA with complex hydrogen bonding interactions. These hydrogen bonding interactions are important for inhibitory activity of EGCG against HSA. We suggested that ECG can be a potent inhibitor of HSA. This study will be helpful to understand the mechanism of inhibition of HSA by EGCG and give insights to develop therapeutic strategies against diabetes.