• Natural Product Sciences
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• v.15 no.4
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• pp.208-212
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• 2009

The heartwood of Rhus verniciflua Stokes (Anacardiaceae) is widely used for a medicinal plant to treat diabetes mellitus and lingering intoxication in the folkloric society of Korea, while the stem bark has been traditionally used to treat menstrual disorder and helminthiasis. We previously reported that a flavonoid, fustin, isolated from the heartwood of R. verniciflua is effective in Alzheimer‘s disease and rheumatoid arthritis. To explore the possibility to produce more flavonoid-rich fraction from this plant, the MeOH extracts from the plant parts of stem bark, outer heartwood, and inner heartwood were quantitatively analyzed by HPLC. Phenolic or flavonoid compounds (chlorogenic acid, caffeic acid, p-coumaric acid, sulfuretin, fustin, fisetin, luteolin and astragalin) were detectable in the HPLC chromatogram. The orange-colored inner heartwood was found to contain the highest levels of fustin (16.96 mg/g) and sulfuretin (2.22 mg/g). Moreover, the inner heartwood accumulated fustin and sulfuretin at least 4-fold higher level as compared to the stem bark and outer heartwood. The levels of total phenolic compounds positively correlated with the extents of antioxidant properties. Therefore, the inner heartwood of R. verniciflua could be used to increase fustin concentration of the extract which is capable of treating Alzheimer‘s disease and rheumatoid arthritis.

• Natural Product Sciences
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• v.15 no.4
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• pp.241-245
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• 2009

In the course of screening for antioxidant compounds by measuring the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging effect and superoxide quenching activity, methanol extract of Cyperus difformis (Cyperaceae) was found to show potent antioxidant activities. Subsequent activity-guided fractionation of the methanolic extract led to the isolation of three phenolic compounds, rosmarinic acid (1), luteolin (2) and caffeic acid (3). Their structures were elucidated by spectroscopic studies. Three compounds showed the significant antioxidative effects on DPPH and nitric oxide radical scavenging effects, riboflavin and xanthin originated superoxide quenching activities. Among them, compound 3 showed the most significant antioxidative effects on those four antioxidant tests. Compound 3 showed better antioxidative activities than vitamin C.

• Ocean and Polar Research
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• v.33 no.3
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• pp.255-263
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• 2011

The aim of this investigation was to evaluate antioxidant activity of crude extracts from the halophyte Vitex rotundifolia, their solvent fractions, and isolated compounds (1-3). Antioxidant capacity was determined by measuring DPPH radical, and authentic $ONOO^-$ and $ONOO^-$ generated from 3- morpholinsydnonimine (SIN-1) in vitro as well as degree of occurrence of intracellular ROS, NO and GSH in mouse macrophage Raw 264.7 cells. From comparative analysis, MeOH extract, n-BuOH, and 85% aq. MeOH solvent fractions showed significant antioxidant effect in DPPH radical and $ONOO^-$ assay systems. Activity-guided purification of n-BuOH and 85% aq. MeOH fractions led to the isolation of flavonoids 1-3. Among them, compound 1 exhibited excellent antioxidant effect in all bioassay systems tested. On the other hand, compounds 2 and 3 revealed potent inhibitory effect against $ONOO^-$ generated from SIN-1, comparable with the positive control penicillamine.

• Journal of Microbiology and Biotechnology
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• v.16 no.7
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• pp.1090-1096
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• 2006

O-Methylation is a common modification reaction found in nature, and is mediated by an O-methyltransferase (OMT). OMTs have been mainly studied in plants, whereas only a few OMTs have been studied in microbes. When searching the Bacillus cereus genome, four putative small molecular OMTs were identified, among which BcOMT-1 was cloned and expressed in E. coli as a his-tag fusion protein. The whole cell expressing BcOMT-1 was used to methylate several flavonoids. Eriodictyol, luteolin, quercetin, and taxifolin, all of which contain 3' and 4' hydroxyl groups, served as methyl group acceptors for BcOMT-1, whereas naringenin, apigenin, 3,3'-dihydroxyflavone, and 3,4'-dihydroxyflavone did not function as substrates. Analysis of the reaction products using HPLC showed two different peaks, and NMR revealed that the methylation position was at the hydroxyl group of either carbon 3' or 4'. Therefore, this showed that BcOMT-1 used flavonoids containing ortho hydroxyl groups and transferred a methyl group to either of two hydroxyl groups.

• Natural Product Sciences
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• v.15 no.2
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• pp.106-109
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• 2009

Phytochemical investigations of the EtOAc-soluble fraction of the whole plants of Salvia plebeia using repeated column chromatography with preparative HPLC led to the isolation of a new phenylbutanone glucoside, 4-{4-0-[6-(4-hydroxybenzoyl)-0-${\beta}$-D-glucopyranosyl]-3-hydroxyphenyl}-butan-2-one (salviaplebeiaside, 1) along with two known phenolic compounds, rosmarinic acid methyl ester (2) and luteolin-7-0-${\beta}$-D-glucoside (3). The structures of these compounds were determined on the basis of spectroscopic methods including 1D-, 2D-NMR and MS spectrometry and comparison of spectroscopic data with those of values reported in the literatures.

• BMB Reports
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• v.29 no.5
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• pp.423-428
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• 1996

A superoxide anion radical scavenger isolated from Capsella bursa-pastoris was characterized by infrared (IR) spectroscopy, sugar analysis, ultraviolet (UV) spectroscopy, $^{1}H$ and $^{13}C$ nuclear magnetic resonance (NMR) spectroscopies, and fast atom bombardment (FAB) mass analysis. The compound was assumed to be a flavonoid-O-glycoside from IR spectrum and UV absorption maxima. When the sugar composition of the compound was examined by thin layer chromatography (TLC) and gas chromatography (GC) of the acid hydrolysate, only glucose was detected. According to the results of UV spectrotroscopy by using shift reagents, the compound was supposed to be luteolin (5,7,3',4'-tetrahydroxy flavone) or chrysoeriol (5,7,4'-trihydroxy-3'-methoxy flavone) with glucose. Based on $^{1}H$- and $^{13}C-NMR$ spectroscopies, the compound was deduced as 7,4'-dihydroxy-5,3'-dimethoxy-${\alpha}$-6-c-glucosyl-${\beta}$-2"-o-glucosyl flavone. In FAB mass analysis the compound was finally characterized as 7,4'-dihydroxy-5,3'-dimethoxy-${\alpha}$-6-c-glucosyl-${\beta}$-2"-o-glucosyl flavone ($C_{29}H_{34}O_{16}$, M.W.=638).

• Biomolecules & Therapeutics
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• v.17 no.1
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• pp.86-91
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• 2009

In our ongoing search for biological components from the Korea endemic plants, the MeOH extract of Ailanthus altissima leaves (Simaroubaceae) showed cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) dual inhibitory activity by assessing their effects on the production of prostaglandin $D_2$ ($PGD_2$) and leukotriene $C_4$ ($LTC_4$) in mouse bone marrow-derived mast cells (BMMCs). In further study, eight compounds, squalene (1), ${\beta}$-sitosterol (2), scopoletin (3), quercetin (4), luteolin (5), astragalin (6), scopolin (7), and daucosterol (8) were isolated, the chemical structures were elucidated on the basis of physicochemical and spectroscopic data and by comparison with those of published literatures. Among the compounds, 2, 4, and 5 strongly inhibited both the COX-2-dependent PGD2 generation with $IC_{50}$ values of 2.6, 7.3 and 2.5 ${\mu}M$, respectively and the generation of $LTC_4$ in the 5-LOX dependent phase with $IC_{50}$ values of 2.0, 5.1 and 1.8 ${\mu}M$, respectively, which suggest that the anti-inflammatory activity of A. altissima might occur in part via the inhibition of both $PGD_2$ and $LTC_4$ generation by 2, 4 and 5.

• Natural Product Sciences
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• v.20 no.3
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• pp.191-195
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• 2014

The n-BuOH soluble fraction of the whole plant of Persicaria thungergii showed acetylcholinesterase inhibitory activity. Four flavonoid glycosides and a flavonoid were isolated from this fraction, and identified as quercitrin (1), luteolin-4'-O-${\beta}$-D-glucopyranoside (2), quercetin (3), quercetin-3-O-glucuronide (4), and isorahmnetin-3-O-glucuronid (5), by chromatographed and spectral data, respectively. All isolated compounds were showed acetylcholinesterase inhibitory activity, with $IC_{50}$ values of 243.1, 10.5, 39.1, 8.2 and $23.2{\mu}M$, respectively.

• Korean Journal of Pharmacognosy
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• v.25 no.1
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• pp.11-19
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• 1994

Gleditsia japonica var. koraiensis NAKAI(Leguminosae) is commonly distributed in Korea and has been used as a folk medicine in the treatment of bronchitis, neoplasm and blennorrhgia in the Orient. The aqueous acetone extract of the leaves of G. japonica was subjected to a combination of Sephadex LH-20, Cosmosil $75C_{18}-OPN$, TSK-gel Toyopearl HW 40F, Avicel cellulose, and MCI-gel CHP 20P chromatographies with various solvent systems. Twelve compounds were isolated and confirmed to be vitexin(1), isovitexin(2), orientin(3), isoorientin(4), 4-caffeoyl quinic acid(5), 5-caffeoyl quinic acid(6), 3, 5-dicaffeoyl quinic acid(7), 4, 5-dicaffeoyl quinic acid(8), caffeic acid(9), quercetin(10), isoquercitrin(11) and luteolin-7-O-glucoside(12), on the basis of chemical and spectroscopic evidences.

• Archives of Pharmacal Research
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• v.17 no.2
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• pp.71-75
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• 1994

The antimutagenic effects of 27 kinds of plant flavonoids on the mutagenicity of aflatoxin $B_1(AFB_1)$ and N-methyl-N'-nitro-N-nitrosoguanidine(MANG) in Salmonella typhimurium TA 100 were investigated. In the mixed applications of $AFB_1\;(1\;\mu{g/plate)}$ with the flavonoids $(300\;\mu{g/plate)}$ in the presence of a mammalian metabolic activation system (S9 mix), chrysin, apigenin, luteolin and its glucoside, kaempferol, fisetin, morin, naringenin, hesperetin, persicogenin, (+)-catechin and (-)epicatechin showed the antimutagenic effect against $AFB_1$ with more than 70% inhibition rate. A little or no antimutagenicities except flavone against MNNG $(0.5\;\mu{g/plate)}$ were observed. For the antimutagencity of the flavonoids on $AFB_1$, the flavonoid structure that contains the free 5, 7-hydroxyl gorup seemed to be essential. However, saturation of the 2, 3-double bond of elimination of the 4-keto group did not affect the activity.