• 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.

• YAKHAK HOEJI
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• v.38 no.3
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• pp.286-292
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• 1994

Poncirin and naringin which are the flavanone rhamnoglucoside showed anti-inflammatory activity as the major component of fruit of Poncirus trifoliata. Poncirin was metabolized by intestinal bacteria of human and rats. Among the human intestinal bacteria, Bacteroides JY-6 converted a poncirin to naringin, ponciretin-${\beta}$-D-glucopyranoside, naringenin-${\beta}$-D-glucopyranoside, naringenin and ponciretin and did a naringin to poncirin, ponciretin-${\beta}$-D-glucopyranoside, naringenin-${\beta}$-D-glucopyranoside, naringenin and ponciretin.

• Korean Journal of Pharmacognosy
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• v.47 no.2
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• pp.110-116
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• 2016

As a part of an ongoing search for natural plants with antioxidant compounds by measuring the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH), a total extract of the aerial parts of Bidens frondosa L. (Compositae) was found to show potent antioxidant activity. Subsequent activity-guided fractionation of the methanolic extract led to the isolation of five compounds, quercetin-3-O-${\beta}$-D-glucopyranoside (1), luteolin-7-O-${\beta}$-D-glucopyranoside (2), 7,8,3',4'-tertrahydroxy-flavanone (3), okanin-4-O-${\beta}$-D-glucopyranoside (4), and okanin (5). Their structures were elucidated by spectroscopic studies. Compounds 3-5 were isolated for the first time from this plant. Among them, compounds 3 and 5 showed the significant radical scavenging effects on DPPH, and compounds 3 and 5 also showed the potent riboflavin and xanthine originated superoxide quenching activities.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.2257-2261
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• 2012

Pinocembrin (5, 7-dihydroxyflavanone) is a flavanone extracted from the rhizome of Boesenbergia pandurata. Our previous studies demonstrated that pinocembrin had no toxicity or mutagenicity in rats. We here evaluated its effects on the initiation and promotion stages in diethylnitrosamine-induced rat hepatocarcinogenesis, using short- and medium-term carcinogenicity tests. Micronucleated hepatocytes and liver glutathione-S-transferase placental form foci were used as end point markers. Pinocembrin was neither mutagenic nor carcinogenic in rat liver, and neither inhibited nor prevented micronucleus formation as well as GST-P positive foci formation induced by diethylnitrosamine. Interestingly, pinocembrin slightly increased the number of GST-P positive foci when given prior to diethylnitrosamine injection.

• Natural Product Sciences
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• v.23 no.4
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• pp.306-309
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• 2017

Microbial transformation of $({\pm})$-6-(1,1-dimethylallyl)naringenin (6-DMAN, 1) and $({\pm})$-5-(O-prenyl) naringenin-4',7-diacetate (5-O-PN, 2) was performed by using fungi. Scale-up fermentation studies with Mucor hiemalis, Cunninghamella elegans var. elegans, and Penicillium chrysogenum led to the isolation of five microbial metabolites. Chemical structures of the metabolites were determined by spectral analyses as $({\pm})$-8-prenylnaringenin (3), (2S)-5,4'-dihydroxy-7,8-[(R)-2-(1-hydroxy-1-methylethyl)-2,3-dihydrofurano]flavanone (4), $({\pm})$-5-(O-prenyl)naringenin-4'-acetate (5), $({\pm})$-naringenin-4'-acetate (6), and $({\pm})$-naringenin (7), of which 5 was identified as a new compound.

• Bulletin of the Korean Chemical Society
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• v.29 no.11
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• pp.2287-2290
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• 2008

• Archives of Pharmacal Research
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• v.19 no.6
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• pp.543-550
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• 1996

Analogues of $2(S)-5, 2^{l}, 5^{l}$-trihydroxy-7, 8-dimethoxyflavanone, a naturally-occurring compound, which had been reported to have potent antitumor activity, were synthesized and examined for the cytotoxicity against three cancer cell lines. Among the intermediate chalcones and synthetic 5-hydroxy-7, 8-dimethoxyflavanone analogues, $({\pm})2^{l}, 5^{l}-dibenzyloxy-5, 7, 8-trimethoxyflavanone$ exhibited about 2-8 times stronger activity than $2(S)-5, 2^{l}, 5^{l}$-trihydroxy-7, 8-dimethoxyflavanone against L1210, K562 and A549 cancer cell lines. In the structure-activity relationship, it is suggested that among analogues of 5-hydroxy-7, 8-dimethoxyflavanone, the existence of two oxygenated groups of para-relation at $C-2^{I} and C-5^{I}$ positions on flavanone B-ring, may be necessary to exhibit effective cytotoxic activity.

• Journal of Microbiology and Biotechnology
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• v.21 no.11
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• pp.1143-1146
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• 2011

Metabolic engineering of plant-specific phenylpropanoid biosynthesis has attracted an increasing amount of attention recently, owing to the vast potential of flavonoids as nutraceuticals and pharmaceuticals. Recently, we have developed a recombinant Streptomyces venezuelae as a heterologous host for the production of flavonoids. In this study, we successfully improved flavonoid production by expressing two sets of genes predicted to be involved in malonate assimilation. The introduction of matB and matC encoding for malonyl-CoA synthetase and the putative dicarboxylate carrier protein, respectively, from Streptomyces coelicolor into the recombinant S. venezuelae strains expressing flavanone and flavone biosynthetic genes resulted in enhanced production of both flavonoids.

• Natural Product Sciences
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• v.14 no.4
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• pp.269-273
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• 2008

Microbial transformation of isoxanthohumol (1), a prenylated flavanone from hops, has resulted in the production of a pair of glucosylated derivatives. The structures of these compounds were elucidated to be (2S)-5-methoxy-8-prenylnaringenin 7-O-${\beta}$-D-glucopyranoside (2) and (2R)-5-methoxy-8-prenylnaringenin 7-O-${\beta}$-Dglucopyranoside (3) based on the spectroscopic analyses.

• Natural Product Sciences
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• v.27 no.3
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• pp.169-171
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• 2021

A new phenolic compound and three known flavonoids isolated from the MeOH extracts of Lespedeza tomentosa. Based on spectral data, the isolated compounds were identified as methyl 4,5-dihydroxy-3-methoxy-2-(3-methylbut-2-en-1-yl)benzoate (1), 1-methoxylespeflorin G₁₁ (2), farrerol (3) and 1-methoxylespeflorin I₂ (4). Methyl 4,5-dihydroxy-3-methoxy-2-(3-methylbut-2-en-1-yl)benzoate (1) is newly isolated from plant source.