• Title, Summary, Keyword: flavan-3-ol

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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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Phenolic Compound from Lepisorus thunbergianus (일엽초의 페놀성 물질)

  • Lee, Min-Won
    • Korean Journal of Pharmacognosy
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    • v.29 no.2
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    • pp.142-145
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    • 1998
  • Two phenylpropanoids and one flavan 3-ol were isolated from Lepisorus thunbergianus (Polypodiaceae, fern), which is used as folkmedicine. Phenylpropanoids were identified as caffeic acid and chlorogenic acid, and flavan 3-ol was elucidated as (-)-epicatechin 7-O-${\beta}$-D-glucoside by physico-chemical and spectral evidences (HMQC, NOESY).

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Inhibiory Effect of Novel Flavan-3-ol isolated Theobroma cacao L. Husk on Glucosyltransferase (Theobroma cacao L. 외피로부터 새로운 Flavan-3-ol 화합물의 Glucosyltransferase 저해효과)

  • An, Bong-Jeun;Kwon, Ik-Boo;Choi, Chung
    • Korean Journal of Food Science and Technology
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    • v.27 no.1
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    • pp.92-96
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    • 1995
  • In the course of our studies, novel flavan-3-ol structure isolated from Theobroma cacao L. husk was established by the thiolysis, desulfurization and spectroscopic method. The structure was identified for cinnamtannin A-2 containing the tetrameric epicatechin and molecular weight was [1153] by FAB-MS negative ion. The inhibitory effect on the glucosyltransferase activity was investigated. Cinnamtannin A-2 showed complete inhibition at 0.03 mM and inhibited on the glucosyltransferase noncompetitively. The hydroxyl group of flavan-3-ol was supposed to be the essential element for inhibition on the glucosyltransferase.

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Structure Determination of Glucosyltransferase Inhibitors from Cacao Bean Husk (Cacao Bean Husk로부터 Glucosyltransferase 저해물질 구조결정)

  • An, Bong-Jeun;Choi, Cheong
    • Applied Biological Chemistry
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    • v.37 no.6
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    • pp.498-502
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    • 1994
  • For glucosyltransferase(GTase) inhibitors, two flavan-3-ols were isolated from Theobroma cacao beam husk. They showed positive reaction with $anisaldehyde-H_2SO_4$ solution, $FeCl_3$ to be confirmed as dimeric flavan-3-ols on TLC and were identified as procyanidin B-1 [(-)-epicatechin-$(4{\beta}{\rightarrow}8)$-catechin] and procyanidin B-3 [(+)-catechin-$(4{\beta}{\rightarrow}8)$-catechin by spectroscopic analysis. Their inhibitory effect on glucosyltranaferase activity was also investigated and procyanidin B-1 showed 50% inhibition at 0.3 mM. They inhibited on the glucosyltransferasa noncompetitively and dimeric flavan-3-ol containing (-)-epicatechin had higer inhibitory activity.

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Flavonoids from the Leaves of Alnus hirsuta (물오리나무 잎의 플라보노이드 화합물)

  • 이민원;정동욱;이연아;박명신;도상학
    • YAKHAK HOEJI
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    • v.43 no.5
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    • pp.547-552
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    • 1999
  • Phytochemical examination of the leaves of Alnus hirsuta, one of the indigenous species grows in Korea, has led to the isolation of one flavan 3-ol and two flavonol glycosides. Structures of these compounds are identified as (-)-epicatechin (1), quercetin $3-O-{\beta}-D-galactopyranoside$ (2), quercetin $3-O-{\beta}-D-galactopyranoside$ (3) by means of physico-chemical and spectral evidences.

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Structure and Isolation of Xanthine Oxidase Inhibitor from Oolong Tea (우롱차로부터 Xanthine Oxidase 저해물질 분리 및 구조)

  • An, Bong-Jeun;Kim, Won-Keuk;Choi, Jang-Youn;Kwon, Ik-Boo;Choi, Cheong
    • Korean Journal of Food Science and Technology
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    • v.24 no.6
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    • pp.558-562
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    • 1992
  • Xanthine oxidase involved in pruine metabolism oxidizes hypoxanthine to xanthine and xanthine to uric acid. The derangement of pruine metabolism results in gout that associates painful deposit of monosodium urate in the cartilage of joints. In the continuous study for natural compound, six flavan-3-ols have been isolated from the leaves of Oolong tea. The structures of procyanidin B-1, B-3, procyanidin B-3-3-O-rhamnose, procyanidin B-1-3-O-gallate, (-)-epicatechin, (-)-epicatechin-3-O-gallate were established by NMR and their inhibitory effect on xanthine oxidase activity was investigated. Flavan-3-ols containing the gallate had a high inhibitory capacity. Procyanidin B-1-3-O-gallate showed complete inhibition at $50\;{\mu}M$ and inhibited on the xanthine oxidase competitively.

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Phenolic Compounds from Barks of Ulmus macrocarpa and Their Antioxidative Activities.

  • Kwon, Young-Min;Yeom, Seung-Hwan;Kim, Min-Ki;Lee, Jae-Hee;Lee, Min-Won
    • Proceedings of the PSK Conference
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    • pp.376.1-376
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    • 2002
  • Phytochemical examination of Barks of Ulmus macrocarpa isolated two flavanone, three flavanonol, three flavan 3-ol and one procyanidin compounds. We also determinated the antioxidative activity of these compounds by measuring the radical scavenging effect on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radicals. Three flavan 3-ol (catechin, epicatechin and catechin-7-O-$\beta$-O-xylopyranoside) and procyanidin B1 showed significant antioxidative activity. (omitted)

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Structure Determination of Anti-plaque Agents for Prevention of Dental Caries from Cccao Bean Husk (Cacao Bean Husk로부터 분리한 충치 예방물질의 구조 결정)

  • 권익부;안봉전유주현이신영
    • KSBB Journal
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    • v.8 no.1
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    • pp.69-74
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    • 1993
  • For an anti-plaque agent, two flavan-3-ols isolated from Theobroma cacao bean husk showed positive reactions with $H_2SO_4$-anisaldehyde solution, $FeCl_3$, and were identified as monomeric, dimeric flavan-3-ots in TLC. They were (-)-epicatechin and procyanidin B-2(epicatechin-(4$\beta$$\rightarrow$8)-epicatechin). The structures were established by spectroscopic and chemical methods. (-)-Epicatechin had moderate inhibitory activity on GTase at concentration of 1.0mM while procyanidin B-2 showed complete inhibition activity at the same concentration. The hydroxyl group of flavan-3-ol was supposed to be the essential element for inhibition on GTase.

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Inhibition Effect of Against Angiotensin Converting Enzyme of Flavan-3-ols isolated Korean Green Tea (한국산 녹차로부터 분리한 Flavan-3-ol 화합물의 Angiotensin Converting Enzyme 저해 효과)

  • Cho, Young-Je;An, Bong-Jeun;Choi, Cheong
    • 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.

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Structural Elucidation of Epicatechin $(4{\rightarrow}7)$ 5,8,3'4'-tetrahydroxy-(2R,3R)-flavan-3-ol Isolated from the Bark of Korean Pine Tree (Pinus densifora)

  • Lim, Yoong-Ho;Yong, Yeun-Joong;Oh, Sung-Jin;Song, Hong-Keun
    • Applied Biological Chemistry
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    • v.41 no.4
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    • pp.265-269
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    • 1998
  • Several flavonoid dimers were isolated and elucidated from the bark of Korean pine tree (Pinus densiflora). One of them was postulated to be a compound, epicatechin $(4{\rightarrow}7)$ 5,8,3',4'-tetrahydroxy-(2R,3R)-flavan-3-ol, whose structural determination was carried out by diverse NMR techniques.

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