• Title, Summary, Keyword: oolong tea

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Inhibitory Effect of Flavan-3-ols Isolated from Oolong Tea on Xanthine Oxidase (우롱차로부터 분리된 Flavan-3-ol 화합물의 Xanthine Oxidase에 대한 저해 영향)

  • An, Bong-Jeun;Bae, Man-Jong;Choi, Chung
    • Korean Journal of Food Science and Technology
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    • v.28 no.6
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    • pp.1084-1088
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    • 1996
  • As a series of study for an anti-gout agent, two flavan-3-ols have been isolated from Oolong tea. They showed positive reaction in $anisaldehyde-H_2SO_4$ solution and $FeCl_3$, which were able to be confirmed in TLC with dimeric flavan-3-ols. The components were identified as procyanidin B-2 and procyanidin B-2-O-3, 3'-di-gallate by spectroscopic analysis. Their inhibitory effect on xanthine oxidase was also investigated and procyanidin B-2-O-3, 3'-digallate showed 60.6% inhibition at $50\;{\mu}mole$. The compound competitively inhibited the xantine oxidase and dimeric flavan-3-ols contanining gallate had higher inhibition activity.

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The Comparison of Antioxidant Capacities and Catechin Contents of Korean Commercial Green, Oolong, and Black Teas (국내 시판되는 녹차, 우롱차 및 홍차의 카테킨 함량과 항산화능 비교)

  • Lee, Min-June;Kwon, Dae-Joong;Park, Ok-Jin
    • Journal of the Korean Society of Food Culture
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    • v.22 no.4
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    • pp.449-453
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    • 2007
  • Using green tea(GT), oolong tea(OT), black tea(BT) and green tea bag(GTB) out of tea products in market, this study quantified polyphenol and catechins as anti-oxidant substances and analyzed their respective anti-oxidant capacities. As a result, more epigallocathechin(EGC) was found in GT and GTB as well as caffein(CAF) in GT and BT. GT contained more epigallocathechin gallate(EGCG) than other tea types. Both FRAP and ORAC, as two methods of analyzing anti-oxidant capacities, showed that GTB had highest anti-oxidant capacities, while OT had lowest of all. By brand, it was found that all the 3 brands of GT had similarly high anti-oxidant capacities, but there were differences in the anti-oxidant activities of GTB and BT depending on brand. Out of catechin components, it was found that epicatechin(EC), epicathechin gallate(ECG) and EGCG were major components affecting anti-oxidant capacities.

Phenolic Content, Antioxidant Effect and Acetylcholinesterase Inhibitory Activity of Korean Commercial Green, Puer, Oolong, and Black Teas (국내 시판 녹차, 보이차, 우롱차 및 홍차의 폴리페놀 함량, 항산화 및 아세틸콜린에스터레이스 저해 효과)

  • Jeong, Chang-Ho;Kang, Su-Tae;Joo, Ok-Soo;Lee, Seung-Cheol;Shin, Young-Hee;Shim, Ki-Hwan;Cho, Sung-Hwan;Choi, Sung-Gil;Heo, Ho-Jin
    • Korean Journal of Food Preservation
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    • v.16 no.2
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    • pp.230-237
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    • 2009
  • The phenolic contents, antioxidant effects, and acetylcholinesterase inhibitory activities of hot water extracts prepared from various Korean commercial teas(green tea, puer tea, oolong tea, and black tea) were investigated. Total phenolic contents were in the range 72.03-85.62 mg/g. Flavonol contents of hot water extracts from green tea, puer tea, oolong tea, and black tea were 350.96, 254.17, 334.48, and 240.23 mg/100 g, respectively. Catechin contents were 2,920.35 mg/100 g in green tea, 1,016.23 mg/100 g in puer tea, 2,824.22 mg/100 g in oolong tea, and 1,006.51 mg/100 g in black tea. The highest caffeine content was in the green tea extract. All four extracts scavenged $ABTS^{{\cdot}+}$ radicals in a concentration-dependent manner, and the green tea extract was the most potent in this regard. The highest reducing power was observed in the green tea extract. All four extracts exhibited considerable antioxidative activities in linoleic acid autoxidation, $\beta$-carotene bleaching, and acetylcholinesterase inhibition assays; the effects were concentration-dependent and decreased in the order green tea > oolong tea > puer tea > black tea.

Desmutagenicity of Tea Extracts from Green Tea, Oolong Tea and Black Tea (녹차, 오룡차 및 홍차 추출물의 돌연변이원성 억제작용)

  • 김선봉;여생규;김인수;안철우;박영호
    • 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.

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Effects of Camellia sinensis Extracts on the Antioxidant System and Alcohol Down-Regulation Enzymes in Sub-Acute Ethanol Treated ICR Mice (차나무(Camellia sinensis) 추출물이 아급성 알코올 투여 마우스의 항산화 및 알코올 분해 효소 활성에 미치는 영향)

  • Koo, Sung-Ja;Choi, Il-Sook;Kong, Yeon-Hee;Choi, Sang-Yoon;Jo, Youn-Ock
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.36 no.9
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    • pp.1134-1139
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    • 2007
  • This study was conducted to investigate the effects of four kinds of tea (Camellia sinensis) extracts on the antioxidant defense systems as well as the activities of alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) in ethanol administered ICR mice. According to the results, treatment with puerh tea significantly increased the superoxide dismutase activity and glutathion reductase activity in liver. In addition, the group treated with oolong tea exhibited higher superoxide dismutase activity and glutathion reductase activity in serum than those of puerh tea, green tea and black tea treated groups. The oolong tea and puerh tea also reduced malondealdehyde contents in both liver and serum. These results suggested that puerh tea and oolong tea were the most effective against alcohol-induced oxidative damage among the Camellia sinensis teas. On the other hand, in the measurement of alcohol break-down enzyme activities, the group treated with green tea exhibited the highest hepatic ADH and ALDH activities, suggesting that the group treated with green tea might be useful for alcohol down-regulation.

A Study on the Catechins Contents and Antioxidative Effect of Various Solvent Extracts of Green, Oolong and Black Tea (녹차, 우롱차 및 홍차의 용매별 추출물의 카테킨류 함량 및 항산화효과에 관한 연구)

  • 이영자;안명수;오원택
    • Journal of Food Hygiene and Safety
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    • v.13 no.4
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    • pp.370-376
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    • 1998
  • The extraction yield of MeOH extract of green teas, oolong tea and black tea were 3 to 5, 4 to 5, and 5 to 7 fold higher than those of EtOH and EtAC extract, respectively. The amount of total catechins of EtAC extract of the black tea, and of the green teas and oolong tea were three- and two-fold higher than that of EtOH or MeOH extract of the corresponding teas, respectively. The antioxidative activities of EtOH, MeOH and EtAc extract were considerably higher than that of BHT and $dl-{\alpha}-tocopherol$ at 200 ppm level. The antioxidative activities of EtOH and MeOH extract at 200 and 500 ppm level, and of EtAc extract at 200 ppm level varied depending on the type of tea as follows : green tea I > green tea II > green tea III > oo-long tea> black tea. The antioxidative activity increased as the content of EGC increased. But the antioxidative activity of MeOH extract at 1000 ppm level, and of EtAc extract at 500 and 1000 ppm level were not affected by the content of EGC and EGCG.

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Effects of Persimmon Leaf Tea Extract, Green Tea Extract and Oolong Tea Extract on the Frequencies of Mutagen-Induced Sister Chromatid Exchange in Chinese Hamster Ovary Cells (감잎차, 녹차, 우롱차 추출물이 돌연변이 물질로 유발된 Sister Chromatid Exchanges 빈도에 미치는 영향)

  • Song, Hyun-Soon;Lee, Hyun-Kul;Choi, Eon-Ho;Kang, Myung-Hee
    • Korean Journal of Food Science and Technology
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    • v.31 no.3
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    • pp.823-830
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    • 1999
  • The suppressing effects of crude extracts of three Korean teas, persimmon leaf tea extract (PLTE), green tea extract (GTE) and oolong tea extract (OTE), were studied on the induction of sister chromatid exchange (SCE) in cultured Chinese hamster ovary cells. When cells were treated with tea extract after mitomycin C (MMC) treatment, the frequency of MMC-induced SCEs were decreased at the high concentration $(1000\;{\mu}g/mL)$ of PLTE in the presence of S9 mix and at low concentrations $(20{\sim}80\;{\mu}g/mL)$ of PLTE in the absence of S9 mix, Whereas GTE and OTE showed suppressing effects on the MMC-induced SCEs at low concentrations $(10{\sim}20\;{\mu}g/mL)$ for OTE and $160\;{\mu}g/mL$ for GTE only in the presence of S9 mix. MMC-induced SCEs were decreased by post-treatment with each tea extracts with S9 mix in the G1 phase of the cell cycle. These results suggest that PLTE, GTE and OTE could have bio antimutagenic activities, and also suggest that PLTE might have unknown antimutagenic components which would be responsible for the inhibitory effect against direct acting mutagenicity.

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Analytical Method for Methylxanthin, Catechin, and Theaflavin Determinations in Korean Commercial Teas by HPLC (차에 함유된 methylxanthin류, catechin류 및 theaflavin류의 HPLC에 의한 동시분석법)

  • Kim, Soo-Yeun;Kozukue, Nobuyuki;Han, Jae-Sook;Lee, Kap-Rang
    • Korean Journal of Food Science and Technology
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    • v.38 no.1
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    • pp.5-9
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    • 2006
  • Method for separation and quantification of methylxanthins, catechins, and theaflavins in Korean commercial teas (green, oolong, and black teas) was developed using reversed phase high-performance liquid chromatography (HPLC). After extraction with hot water, tea compounds were separated on Inertsil ODS-3v $(5\;{\mu}m)$ column, eluted with gradient of 7% acetonitrile and 93% of 20 mM phosphate buffer mixture for 7 min. Column effluent was monitored at 270 nm. This technique was effective for analyses of m methylxanthins, catechins, and theaflavins in teas and biological samples. In green and oolong teas, two kinds of methylxanthins and 7 of catechins were identified, whereas 4 theaflavins were only identified in black tea. Among seven catechins in green and oolong teas, EGCG showed highest amount, whereas ECG was highest in black tea. (theaflavins were found only in black teas) In all teas, theobromine content was lower than that of caffeine.