• 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).

• 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.

• 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.

• 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.

• 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.

• 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.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.376.1-376.1
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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)

• 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.

• 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.

• 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.