• 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.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).

• Journal of the Korean Wood Science and Technology
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• v.28 no.4
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• pp.25-28
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• 2000

Two flavan 3,4-diol derivatives were isolated from the heartwood of Robinia pseudoacacia and characterized by spectroscopic methods including $^1H$ and $^{13}C$ NMR and positive FAB-MS. The structures were identified as 2,3-trans-3,4-cis-3,4,7,3',4',5'-hexahydroxy flavan, one of isomeric leucorobinetinidins, and 4'-methoxy-2,3-trans-3,4-cis-3,4,7,3',5'-pentahydroxy flavan.

• 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.

• 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.

• 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.

• Journal of the Korean Wood Science and Technology
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• v.29 no.3
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• pp.99-103
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• 2001

Three flavan-3,4-diol derivatives were isolated from the heartwood of Robinia pseudoacacia and characterized by spectroscopic methods including $^1H$ and $^{13}C$ NMR and positive FAB-MS. The structures were identified as 4,4'-dimethoxy-, 4-ethoxy- and 4-ethoxy-4'-methoxy-2,3-trans-3,4-cis-(+)-leucorobinetinidin.

• Journal of the Korean Wood Science and Technology
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• v.48 no.6
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• pp.888-895
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• 2020

Ulmus genus has excellent various physiological activities, including anti-ulcer, antioxidant, antibacterial, anti-cancer, immunity, and homeostasis maintenance effects, and it is known to have many additional drug effects And one of reasons for these excellentbiological activities is a flavan-3-ol chemical group in Ulmus genus. In this study a new flavan-3-ol compound was identified in Ulmus davidiana var. japonica. A flavan-3-ol,(2R,3S)-7-[(2S,3R,4R)-3,4-dihydroxy-4-(hydroxymethyl)oxolan-2-yl]oxy-2-(3,4-dihydroxyphenyl)-3,4-dihydro-2H-chromene-3,5-diol, named as catechin 7-O-beta-D apiofuranoside, was isolated from the stems and barks of Ulmus davidiana var. japonica for. suberosa, which is a species belonging to the genus Ulmus, growing throughout the Korea peninsula. The structure was elucidated by various spectroscopic methods including high-resolution TOF mass spectrometry, ¹H-NMR and ¹³C-NMR spectrometry and comparison with chemical structures of defined compounds.

• Journal of the Korean Wood Science and Technology
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• v.29 no.4
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• pp.53-59
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• 2001

The needles of torreya(Torreya nucifera S. et Z) were collected, extracted with acetone-$H_2O$(7:3, v/v), fractionated with hexane, chloroform and ethylacetate, and freeze dried to give some dark brown powder. The ethylacetate soluble mixture was chromatographed on a Sephadex LH-20 column using a series of aqueous methanol and ethanol-hexane mixture as eluents. Most of the needle extractives were flavan and its methyl ether compounds such as (+)-catechin, (-)-epicatechin, (+)-gallocatechin, (-)-epigallocatechin, 3'-O-methyl-(+)-catechin and 3'-O-methyl-(-)-epicatechin including protocatechuic acid, one of benzoic acids. $^1H$- and $^{13}C$-NMR, NOE and CI-MS analyses were performed to elucidate the structures of the isolated compounds.

• 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.