• 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.

• Archives of Pharmacal Research
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• v.15 no.3
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• pp.211-214
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• 1992

Chemical examination of Betula platyphylla var. latifolia afforded a novel diarylheptanoid named betulateraol, together with a phenylpropanoid (3, 4'-dihydroxypropio-phenone), flavan-3-ol [(+)-catechin] and its glycosides [(+)-catechin 5-O-$\beta$-glucopyranoside, (+)-catechin 7-0-$\beta$-D-glucopyranoside] and two proanthocyanidins (procyanidins B-1 and B-3).

• Nutrition Research and Practice
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• v.6 no.1
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• pp.68-77
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• 2012

Flavan-3-ols are a subclass of flavonoids found in a variety of foods including teas. The effects of flavan-3-ols on the risk of metabolic syndrome (MetS) have been investigated, generally focusing on tea catechins or individual flavan-3-ol rich foods, but there is little information on dietary flavan-3-ols intake and risk of MetS in population-based studies. In this cross-sectional study, we examined the association between dietary flavan-3-ols intake and the risk of MetS in Korean adults. Subjects comprised 1,827 men and 2,918 women aged 20-69 years whose data was included in the 2008 Korean National Health and Nutrition Examination Survey. This survey was conducted between January 2008 and December 2008. Total flavan-3-ols intakes were calculated from 24-hour dietary recalls using a flavonoids database. Thirty percent of the male subjects and 24% of the female subjects were reported as having MetS. In the female subjects, flavan3-ols intake was inversely associated with the risk of MetS after adjusting for potential confounders (5th vs. 1st quintile, OR=0.64, 95% CI=0.45-0.91, P for trend=0.384). The main food source of flavan-3-ols was green tea followed by apples and grapes. Among MetS components, flavan-3-ols intake was inversely associated with the risk of high blood pressure after adjusting for potential confounders (5th vs. 1st quintile, OR=0.64, 95% CI=0.45-0.90, P for trend=0.005). No significant association between flavan-3-ols intake and risk of MetS was found in the male subjects. After stratified analysis by obesity (BMI ${\geq}$ 25 or BMI < 25), however, flavan3-ols intake was inversely related to the risk of hypertension in non-obese men. These results suggest that dietary flavan-3-ols intake may have beneficial effects on MetS risk by reducing the risk of hypertension. The effects of flavan-3-ols intake dependent on obesity need further investigation.

• Korean Journal of Pharmacognosy
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• v.26 no.1
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• pp.27-30
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• 1995

Tannins were isolated from the stems of Rubus coreanum and identified as (-)-epicatechin, (+)-catechin, procyanidin B-4 and sanguiin H-4 by spectral analysis.

• KSBB Journal
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• v.11 no.5
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• pp.536-542
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• 1996

The isolation of active compounds showing the inhibitory effect on glucosyltransferase(GTase) from cacao bean husk(CBH) extract was carried out for screening of anti-plaque agents. These active compounds were purified by additional column chromatography of MCI-gel CHP-20 and Sephadex LH-20 and their chemical structures were determined by NMR and mass spectroscopy. Two compounds showing the inhibitory effect on GTase from CBH extract were obtained. These compounds showed positive reactions with anisaldehyde-H2SO4 solution and FeCl3, and were identified as dimeric flavan-3-ols on TLC. By NMR and MS data analyses, the structures of two different flavan-3-ols were identified as procyanidin B-1 and procyanidin B-3, respectively.

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1304-1308
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• 1997

In the course of studies for anti-plaque agents, novel procyanidin structure isolated from Artocarpus heterophyllus folium was established by thiolysis and spectroscopic analysis. The chemical structure was identified for $(-)-epiafzelecin-(4{\beta}{\rightarrow}8)-afzelecin-(4{\alpha}-8)-catechin$ containing the trimeric flavan-3-ols and molecular weight was 833[M-H] by FAB-MS negative ion method. The inhibitory effect on the glucosyltransferase activity was investigated, novel compound showed complete inhibition at 1.0 mM and inhibited on the glucosyltransferase noncompetitively.

• Korean Journal of Pharmacognosy
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• v.30 no.4
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• pp.397-403
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• 1999

Tyrosinase plays an important role in the process of melanin polymer biosynthesis. Therefore, the enzyme inhibitors have been of great concern as cosmetics to have skin-whitening effects on the local hyperpigmentation. During the search for new inhibitory compounds on melanin polymer biosynthesis from natural sources, MeOH extracts of 589 higher plants were tested for the inhibitory effect on tyrosinase activity by the muschroom tyrosinase assay in vitro. Among plants tested, the leaves of Cercis chinensis exhibited potent inhibitory effect on mushroom tyrosinase activity. Subsequently seven active compounds were isolated from the ethyl acetate soluble part of acetone extract of the leaves of C. chinensis by the activity guided fractionation monitoring the inhibitory effect on tyrosinase activity. Their chemical structures were identified as $kaempferol-3-0-{\alpha}-L-rhamnoside$, quercitrin, $myricetin-3-0-{\alpha}-L-rhamnoside$, myricetin-3-0-(2'-O-galloyl)- ${\alpha}$ -L-rhamopyranoside (desmanthin), (-)-epicatechin-3-0-gallate, (-)-epigallocatechin-3-0-gallate, and methyl gallate on the basis of the speculation of spectral data and chemical reaction. Among the flavonol rhamnosides, myricetin-3-0-(2'-O-galloyl)- -L-rhamnoside(desmanthin) showed most potent inhibitory effect on tyrosinase activity and the structure of B-ring in flavonol moiety was related to the activity. (-)-Epigallocatechin-3-O-gallate having pyrogallol group in flavan-3-ol moiety exhibited more potent inhibitory effect than (-)-epicatechin-3-0-gallate having catechol group in flavan-3-ol moiety on mushroom tyrosinase activity.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.1001-1012
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• 2009

A total of 49 phenolic compounds were identified from the aged red wines made from Cabernet Gernischt (Vitis vinifera L. cv.) grapes, a Chinese characteristic variety, including 13 anthocyanins, 4 pryanocyanins, 4 flavan-3-ol monomers, 6 flavan-3-ol polymers, 7 flavonols, 6 hydroxybenzoic acids, 5 hydroxycinnamic acids, 3 stilbenes, and 1 polymeric pigment. Evolution of these compounds was investigated in wines aged 1 to 13 months. Variance analysis showed that the levels of most phenolics existed significant difference in between wines aged 3 and 9 months. Cluster analysis indicated that 2 groups could be distinguished, one corresponding to wines aged 1 to 3 months and the other to wines aged 4 to 13 months. It was thus suggested that there were 2 key-stages for the development of fine wine quality, at the aged 3 and 9 months, respectively. This work would provide some helpful information for quality control in wine production.

• Natural Product Sciences
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• v.16 no.1
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• pp.10-14
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• 2010

Phytochemical examination of the barks of Pinus densiflora Siebold et Zuccarini has led to the isolation of one phenylpropanoid, one lignan, one flavonoid, one flavan 3-ol and two procyanidins : 4-O-$\beta$-D-glucopyranosyl-p-coumaric acid (1), 2,3-dihydro-2-(4-methoxy)-7-hydroxy-3-hydroxymethyl-5-(3-hydroxy propyl)-benzofuran 3-O-$\alpha$-D-glucopyranoside (2), taxifolin 3'-O-$\beta$-D-glucopyranoside (3), (+)-catechin (4), procyanidin B1 (5) and epicatechin-($4{\beta}$-8)-catechin-($4{\alpha}$-8)-catechin (6). Among them, Compound 4, 5 and 6 showed potent anti-oxidative activities and these anti-oxidative activities were significantly different compared with ascorbic acid as positive control.

• Korean Journal of Pharmacognosy
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• v.33 no.4 s.131
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• pp.404-410
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• 2002

Phytochemical examination of Barks of Ulmus macrocarpa has led to the isolation and characterization of two fla-vanonol, taxifolin $7-O-{\beta}-D-glucopyranoside$ (1), taxifolin $3'-0-7-{\beta}-glucopyranoside$ (2), two flavanone eriodictyol $7-O-{\beta}-D-glucopyranoside$ (3), nalingenin $7-O-{\beta}-D-glucopyranoside$ (4), three flavan 3-ol, (+)-catechin (5), (-)-epicatechin (6), (+)-catechin 7-O-{\beta}-D-glucopyranoside (7) and one proanthocyanidin, procyanidin B-1 (8). Antioxidative activity of these compounds was determined by measuring the radical scavenging effect on 1,1-diphenyl-2- picrylhydrazyl (DPPH) radicals . (+)-Catechin (5) , (-)-epicatechin (6), (+)-catechin $7-O-{\beta}-D-glucopyranoside$ (7) and procyanidin B-1 (8) showed significant antioxidative activity.