• Title, Summary, Keyword: catechins

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Analysis by HPLC of Catechins, Alkaloids and Antioxidant Activities in Hadong Green Tea Leaves (HPLC를 이용한 하동 녹차의 Catechin류, Alkaloid류 분석 및 항산화능 측정)

  • Lee, Mi-Hee;Lee, Sung-Un
    • Journal of the Korean Applied Science and Technology
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    • v.30 no.4
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    • pp.761-769
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    • 2013
  • This study used HPLC to analyze the contents of catechins, alkaloids, theanine, total phenolic compounds and antioxidant activities of commercial Hadong green tea leaves(Uzen, Sezak, Jungzak, Daezak). The content of catechins, alkaloids, theanine, total phenolic compounds were lower by water extracts than by 80% ethanol-water extracts. Total catechin and alkaloid contents in Uzen(172.33 mg/g, 30.80 mg/g) by 80% ethanol extract were the highest. Theanine contents of 80% ethanol-water extracts ranged form 55.36 to 37.48 mg/g of tea leaves. Total phenloic compounds contents of green tea were higher than Uzen. Antioxidative of green tea by DPPH, FTC, TBA method were higher than that Uzen.

Effects of Green Tea Catechins on the Lipid Peroxidation and Superoxide Dismutase (녹차카테킨이 지질과산화 및 Superoxide Dismutase에 미치는 영향)

  • 강원식;이윤희;정현희;강민경;김택중;홍진태;윤여표
    • Journal of Food Hygiene and Safety
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    • v.16 no.1
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    • pp.41-47
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    • 2001
  • The purpose of this study was to elucidate the effects of green tea catechins (GTC) on the lipid peroxidation and superoxide dismutase (SOD). GTC showed the high SOD activity, while sitgnificantly inhibited the peroxide value of linoleic acid (93%) and lipid peroxidation (84%) from rat liver microsomal fraction induced by Fe$^{2+}$ascorbate system. The effects of GTC on the SOD and catalase activities, and lipid peroxidation after oral administration were investigated. GTC (50 mg/kg) significantly increased SOD (62%) and catalase activities (75%), while significantly inhibited the lipid peroxidation (52%) of rat liver microsome in a dose-dependent manner. These results suggest that GTC has the antioxidative effect which is rotated to the prevention of aging and cancer.r.

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The Effects of Green Tea Catechins on Vascular Smooth Muscle Tension and 45 $Ca^{2+}$ Uptake (녹차 카테킨류의 혈관장력 및 $Ca^{2+}$유입에 미치는 영향)

  • 안희열;이미애;윤여표
    • Journal of Food Hygiene and Safety
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    • v.11 no.2
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    • pp.83-87
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    • 1996
  • The objective of this study is to investigate the direct effects of green tea catechins(GTC) on vascular smooth muscle tension and 45Ca2+ Uptake in rat aorta. The methods used in this study are isometric tension measurements using physiograph, Lanthanum method for 45Ca2+(2 uCi/ml) uptake measurement in rat aorta. GTC modified tension induced by 40 mM KCl or 1 uM norepinephrine in rat aorta. Low concentrations of GTC(<0.5mg/ml) increased tension by 40 mM KCl or 1 uM norepinephrine, individually. However, high conecentration of GTC(>0.5 mg/ml) inhibiited tension by 40 mM KCl or 1 uM norepinephrine, individually. GTC increased 45Ca uptake induced by 40 mM KCl in a dose-dependent manner. From these results, GTC has the dual actions in vascular smooth muscle in vitro. Low concentrations of GTC augments tension by K or norepinephrine. However, high concentrations of GTC inhibits tension by K or norepinephrine GTC may have Ca2+ channel activation, action, which may result in unphysiological vasodilation by Ca2+ overload in vascular smooth muscle.

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Antioxidant activity and analysis of proantbocyanidins from pine (Pinus densiflora)needles

  • Park, Yong-Soo;Jeon, Min-Hee;Hwang, Hyun-Jung;Park, Mi-Ra;Lee, Sang-Hyeon;Kim, Sung-Gu;Kim, Mi-Hyang
    • Nutrition Research and Practice
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    • v.5 no.4
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    • pp.281-287
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    • 2011
  • In this study, we evaluated the antioxidant activity of pine needle extracts prepared with hot water, ethanol, hexane, hot water-hexane (HWH), and hot water-ethanol (HWE), using the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical method. The hot water extract possessed superior antioxidant activity than the other extracts. We also compared the antioxidant activity of pine needle extracts through ROS inhibition activity in a cellular system using MC3T3 E-1 cells. The hot water extract exhibited the lowest ROS production. The pattern of HPLC analysis of each extract indicated that the hot water extract contained the highest proanthocyanidin level. The pine needle hot-water extract was then isolated and fractionated with Sephadex LH-20 column chromatography to determine the major contributor to its antioxidant activity. The No.7 and 12 fractions had high antioxidant activities, that is, the highest contents of proanthocyanidins and catechins, respectively. These results indicate that the antioxidant activity of procyanidins from the hot water extract of pine needles is positively related to not only polymeric proanthocyanidins but also to monomeric catechins. Moreover, the antioxidant activity of the pine needle hot water extract was similar to well-known antioxidants, such as vitamin C. This suggests that pine needle proanthocyanidins and catechins might be of interest for use as alternative antioxidants.

Catechins, Theaflavins and Methylxanthins Contents of Commercial Teas (시판 차류의 Catechins, Theaflavins 및 Methylxanthins 함량에 관한 연구)

  • Kim Soo-Yeun;Kozukue Nobuyuke;Han Jae-Sook;Lee Kap-Rang
    • Korean journal of food and cookery science
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    • v.21 no.3
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    • pp.346-353
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    • 2005
  • CThis study used HPLC to analyze the contents of 7 kinds of catechins, 4 kinds of theaflavins, and 2 kinds of methylxanthines in the following 6 kinds of commercial Korean tea: 2 green, 2 black, 1 jasmine and loolong. The following ranges in the 13 tea components of the 6 samples by ethanol extract were evaluated in mg/g: (-)-epigallocatechin, 0(black tea and jasmine tea) to 14.19(green tea); (-)-catechin 0; (+)-epicatechin, 0.62(bran rice-green tea) to 2.91(black tea); (-)-epigallocatechin gallate, 4.59(black tea) to 43.96(jasmine tea); (-)-gallocatechin gallate, 0.58(black tea) to 5.80(jasmine tea); (-)-epicatechin gallate, 5.63(bran rice-ueen tea) to 48.06(jasmine tea): (-)-catechin gallate, 0.26(black tea): theaflavif 0 to 3.66(black tea): theaflavin-3-gallate, 0 to 6.94(black tea): theaflavin-3'-gallate, 0 to 4.01(black tea); theaflavin-3,3-digallte, 0 to 10.25(black tea); caffeine, 4.60(bran rice-peen tea) to 26.44(black tea); and theobromine, 0.10(bran rice-green tea) to 1.81(jasmine tea). The contents of all components were lower by water extract than by ethanol extract. Therefore, total catechin (100.55, 45.88 mg/g) and theobromine (1.81, 0.86 mg/g) contents in jasmine tea, and theaflavin content (24.88, 1.36 mg/g) in black tea by ethanol and water extract were the highest. Caffeine content was the highest in black tea(96.48 mg/g) for the ethanol extract, and in jasmine tea (12.38 mg/g) for the water extract.

Development of Green Tea Beverage with Organic Tea Leaves (유기농 녹차잎을 이용한 녹차음료의 개발)

  • An, Mi-Kyoung;Ahn, Jun-Bae;Lee, Kwang-Geun
    • Korean Journal of Food Science and Technology
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    • v.40 no.5
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    • pp.485-490
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    • 2008
  • In this study, organic tea leaves were characterized with the aim of developing an organic beverage process. The green tea leaves grown using organic farming techniques were collected in Haenam, Korea. Catechins in green tea leaves were extracted by chloroform and ethyl acetate and these were then analyzed quantitatively and qualitatively by HPLC (high pressure liquid chromatography). The color and pH values of the green tea extracts were also measured. The catechin levels of April-harvested, May-harvested and June-harvested, semi-fermented leaves at 0.5% were 66.24, 29.19, 57.11, and 5.27 ${\mu}g/mL$, respectively. Among the detected catechins, the level of (-)-epigallocatechin gallate was the highest while that of (-)-epigallocatechin was not detected. The June-harvested leaves were selected as raw material for development of the green tea beverage, based on the levels of catechins, economic viability and yield of tea extract. As the level of extract increased, the levels of catechins of 0.1, 0.2, 0.5% also increased by 1.5, 11.78 and 41.01 times. From the results of the sensory evaluation of June-harvested leaf-extract, the sensory score of color was the highest in 0.1%, while the flavor and overall quality were the highest in 0.2%.

Comparative Analysis of Catechins and Antioxidant Capacity in Various Grades of Organic Green Teas Grown in Boseong, Korea (보성산 유기농 녹차의 품질에 따른 카테킨 함량과 항산화능 비교 분석)

  • Park, Kyung-Ryun;Lee, Sang-Gil;Nam, Tae-Gyu;Kim, Young-Jun;Kim, Young-Rok;Kim, Dae-Ok
    • Korean Journal of Food Science and Technology
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    • v.41 no.1
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    • pp.82-86
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    • 2009
  • The objective of this study was to evaluate the effect of various solvents on extraction of bioactive phenolics and to analyze the antioxidant capacity and contents of individual catechins in various grades of green teas organically grown in Boseong, Korea. The organic green teas, based on their harvest seasons, were categorized into five grades such as Woo-Jeon, Se-Jak, Jung-Jak, Dae-Jak, and coarse tea. Solvents used to extract phenolics from these teas included water at $23^{\circ}C$ and $70^{\circ}C$ as well as 80% (v/v) aqueous methanol and ethanol. In general, aqueous organic solvents of methanol and ethanol led to higher extraction yields of phenolics than water at $23^{\circ}C$ and $70^{\circ}C$. Total phenolics and antioxidant capacity of the teas extracted with the aqueous organic solvents were approximately 1.5 to 3.2 and 1.8 to 3.8 times higher than those with water at $23^{\circ}C$ and $70^{\circ}C$, respectively. Coarse tea, the lowest grade of green tea, showed approximately 30-60% lower total phenolics and antioxidant capacity compared with the higher grade ones. Reversed-phase HPLC analysis was performed quantitatively to identify individual catechins, gallic acid, and caffeine in teas extracted with 80% (v/v) aqueous methanol. Based on their dry weights, the organic green teas contained about 1.7 to 2.9% of caffeine. Content (mg/g dry weight) of tea catechins decreased in the following order: Woo-Jeon (155.4) > Se-Jak (147.7) > Jung-Jak (143.2) > coarse tea (135.1) > Dae-Jak (130.5). (-)-Epigallocatechin gallate was the most abundant among the catechins analyzed. The highest grade of green tea, Woo-Jeon, had the highest amount of (-)-epigallocatechin gallate at 77.4 mg/g dry weight. Overall, the higher grade of organic green teas tended to have the higher level of antioxidant capacity and catechins.

Phenolic Compounds in Persimmon Fruits and Stabilization of Discoloring Compounds (감의 페놀성 화합물과 변색관련 물질의 안정화)

  • 박용곤;김홍만;강윤한
    • The Korean Journal of Food And Nutrition
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    • v.13 no.2
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    • pp.103-110
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    • 2000
  • This study was conducted to determine changes in phenolic compounds of astrigent persimmons before and after softening process and evaluate discoloring properties of major phenolic compounds. Phenolic compounds in soft persimmons were mainly composed of catechins and chlorogenic acid. Although contents of phenolic compounds were reduced during the softening process, little change in the ratio of catechins to total phenolic compounds was observed. Most of phenolic compounds in damaged astringents persimmons were existed in the high molecular weight fraction and more phenolic compounds were extracted at the temperature higher than room temperature. To evaluate discoloring abilities of phenolic compounds, phenolic compounds were dissolved separately into water or 80% methanol. With presence of various amounts of anti-discoloring agents such as vitamin C, citric acid, and L-cystein, (+)catechin was significantly reduced.

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[$^{13}C-NMR$ of the Phenolic Compounds

  • Ahn, Byung-Zun
    • Korean Journal of Pharmacognosy
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    • v.11 no.3_4
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    • pp.153-162
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    • 1980
  • 1) The hydroxy-substitution in the simple phenolic compounds follows an additivity rule in the chemical shifts of their aromatic carbon atoms. In para-and ortho-effects is a good agreement between calculated and measured values, but the meta-effect is not certain. 2) The additivity rule was applied to assign the chemical shifts of catechins. 3) The nuclear overhauser effect was applied to assign the chemical shifts of C-8 and C-6 atoms of catechins and their polymer. The signal of C-8 is lower in intensity and appear in lower field than C-6. 4) The results of the NOE were applied to determine the bonding positions of catechin units in the catechin dimer and trimer. The bonding positions are C-8a and C-8b atoms of the second and third catechin units. 5) It was tried to determine the conformation of the catechin dimer and trimer by analysing the signal shapes of C-3' and C-4' atoms in the catechol moieties. The catechol moieties lie in opposite side in the dimer and trimer structure. A combined analysis of $^{13}C-and\;^1H-NMR$ results lead to the suggestion that such a catechin polymer is a zigzag planar form.

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Green Tea Catechins as a BACE1 ($\beta$-Secretase) Inhibitor

  • Jeon, So-Young;Lee, Hee-Ju;Kim, Ji-Eun;Bae, Ki-Hwan;Seong, Yeon-Hee;Song, Kyung-Sik
    • Proceedings of the PSK Conference
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    • pp.212.2-212
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    • 2003
  • In the course of searching for BACE1 (${\beta}$-secretase) inhibitors from natural products, the ethyl acetate soluble fraction of green tea, which was suspected to be rich in catechin content, showed potent inhibitory activity. (-)-Epigallocatechin gallate, (-)-epicatechin gallate, and (-)-gallocatechin gallate ware isolated with IC$\_$50/ values of 1.6${\times}$10$\^$-6/ M, 4.5${\times}$10$\^$-6/ M, and 1.8${\times}$10$\^$-6/ M, respectively. Seven additional authentic catechins were tested for a fundamental structure-activity relationship. (-)-Catechin gallate, (-)-gallocatechin, and (-)-epigallocatechin significantly inhibited BACE1 activity with IC$\_$50/ values of 6.0${\times}$10$\^$-6/ M, 2.5${\times}$10$\^$-6/ M, and 2.4${\times}$10$\^$-6/ M, respectively. (omitted)

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