• Applied Biological Chemistry
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• v.43 no.4
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• pp.314-316
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• 2000

• Natural Product Sciences
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• v.3 no.1
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• pp.8-10
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• 1997

A new flavonol glycoside, quercetin 3-rhamnosyl $(1{\rightarrow}3)$ galactoside [5] was isolated from the leaves of M. africana. The known compounds kaempferol 3-rutinoside [1], 3'-O-methylquercetin 3-rutinoside [2], quercetin 3-rutinoside [3], and quercetin 3-rhamnosyl $(1{\rightarrow}6)$ galactoside [4] were also isolated for the first time from this plant. Their structures were determined by chemical and spectroscopic methods.

• Korean Journal of Pharmacognosy
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• v.47 no.4
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• pp.295-300
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• 2016

Flavonoids are widely reported to be beneficial to human health. Among flavonoids, in general, flavonoid aglycons have better biological activities than flavonoid glycosides, in that aglycons can easily penetrate through cell membrane because of their low polarity. Therefore, kaempferol, quercetin and various their glycosides were evaluated for their abilities to inhibit NO and $PGE_2$ productions in LPS-induced RAW 264.7 cells. Of these flavonoids and flavonoid glycosides, kaempferol-7-O-${\beta}$-D-glucoside(kp-7-glu) which possesses a glycoside at C-7 position of the A ring in kaempferol, potently inhibited NO, $PGE_2$ and $TNF-{\alpha}$, $IL-1{\beta}$, IL-6 productions in LPS-induced RAW 264.7 macrophages.

• YAKHAK HOEJI
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• v.49 no.5
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• pp.416-421
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• 2005

Cudrania tricuspidata Bereau (Moraceae) have been used for anti-inflammatory, anti-hepatotoxic, anti-hyper­tensive and anti-diabetic activities. In order to investigate the efficacy of antioxidant activity, the bio-activity guided fraction and isolation of Biologically active substance were performed. $H_{2}O,\;30\%,\;60\%,\;100%$ MeOH and acetone fractions were examined on the antioxidant activity by DPPH method. It was shown that $30\%,\;60\%,\;100\%$ MeOH fractions have sig­nificantly antioxidant activity. From $30\%$ MeOH fraction, two dihydroflavonoid glycosides dihydroquercetin 7-O-$\beta$-D-glu­copyranoside (I), dihydrokaempferol 7-O-$\beta$-D-glucopyranoside (V) were isolated and $60\%$ MeOH fraction, six flavonoids including quercetin 3-O-$\alpha$-L-rhamnopyranosyl($1\rightarrow6$)-$\beta$-D-glucopyranoside (II), quercetin 3-O-$\beta$-D-glucopyranoside (III), quercetin 7-O-$\beta$-D-glucopyranoside (IV), kaempferol 3-O-$\alpha$-L-rhamnopyranosyl($1\rightarrow6$)-$\beta$-D-glucopyranoside (VI), kaempferol 3-O-$\beta$-D-glucopyranoside (VII), kaempferol 7-O-$\beta$-D-glucopyranoside (VIII) were isolated. To investigate the antioxidant activities of each compounds, we measured radical scavening activity with DPPH method and anti-lipid per­oxidative efficacy on low density lipoprotein (LDL) with TBARS assay. Four compounds of quercetin glycosides (I, II, III, IV) showed significant antioxidant activity.

• Korean Journal of Pharmacognosy
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• v.29 no.3
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• pp.231-236
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• 1998

Three flavonoid glycosides have been isolated from the aerial part of Armoracia rusticana P. (Cruciferae) in Korea and identified by means of spectral analysis as $kaempferol-3-O-{\beta}-D-xylofuranoside(l)$, $kaempferol-3-O-{\beta}-D-galactopyranoside(2)$ and $kaempferol-3-O-{\beta}-D-xylofuranosyl(1\rightarrow2)-b{\beta}-D-galactopyranoside(3)$. When 1 mg/ml of the methanol extract from the aerial part of this plant was added, lipid peroxide formation in the bromobenzene-treated rat liver decreased by 64%. Among the components isolated from title plant, compounds 2 and 3 reduced the formation of lipid peroxide by 16% and 39% respectively at the concentration of ${10}^{-1}$ mg/ml.

• Food Science and Biotechnology
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• v.14 no.1
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• pp.58-63
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• 2005

Ethyl acetate-soluble neutral fraction of hot water extracts from the aerial parts of Angelica keiskei showed a 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity. Six antioxidative compounds were purified and isolated by various chromatographic procedures. Based on the analyses of FAB-MS and NMR, the isolated compounds were structurally elucidated as luteolin 7-O-${\beta}$-D-glucopyranoside (1), quercetin 3-O-${\beta}$-D-galactopyranoside (2), quercetin 3-O-${\beta}$-D-glucopyranoside (3), quercetin 3-O-${\alpha}$-D-arabinopyranoside (4), kaempferol 3-O-${\alpha}$-D-arabinopyranoside (5), and luteolin 7-O-rutinoside (6). The glycosides of flavonols and luteolin showed DPPH radical-scavenging activity. One molecule of 2, 3, 4, 6, 1, and 5 scavenged 4.2, 4.2, 4.1, 2.5, 2.2, and 1.4 molecules of DPPH radical, respectively.

• Applied Biological Chemistry
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• v.41 no.2
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• pp.197-200
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• 1998

The MeOH extracts obtained from the flower petals of Carthamus tinctorius were solvent-fractionated with EtOAc, n-BuOH, and $H_2O$, successively. From the n-BuOH extract 2 flavonoid compounds were isolated through the repeated silica gel column chromatographies. From not only the results of physico-chemical data including HMBC but also the adaptation of acid hydrolysis, the chemical structures of the compounds were determined as $3-O-[{\beta}-D-glucopyranosyl(1{\rightarrow}2)\;{\beta}-D-glucopyranosyl]\;kaempferol$ and $3-O-[{\alpha}-L-rhamnopyranosyl(1{\rightarrow}6)\;{\beta}-D-glucopyranosyl]\;kaempferol$. The compounds exhibited $IC_{50}$ values in Grab2-Shc activity to be 43 and $47{\mu}g/ml$, respectively.

• Applied Chemistry for Engineering
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• v.29 no.1
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• pp.49-55
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• 2018

In this study, we investigated the cellular protective effects and mechanisms of nicotiflorin and its aglycone kaempferol isolated from Annona muricata. The protective effect of these components against $^1O_2$-induced cell damage was also studied by using L-ascorbic acid and (+)-${\alpha}$-tocopherol as controls. Kaempferol exhibited the most potent protective effect, followed by (+)-${\alpha}$-tocopherol and nicotiflorin. L-Ascorbic acid did not exhibit any cellular protective effects. To elucidate the mechanism underlying protective effects, the quenching rate constant of the singlet oxygen, free radical-scavenging activity, ROS-scavenging activity, and uptake ratio of the erythrocyte membrane were measured. The results showed that the cell membrane penetration is a key factor determining the cellular protective effect of kaempferol and its glycoside nicotiflorin. The result from L-ascorbic acid demonstrated that the cellular protective effect of a compound depends on its ability to penetrate the cell membrane and is independent of its antioxidant capacity. In addition, it is suggested that cellular protective effects of kaempferol and (+)-${\alpha}$-tocopherol depend not only on the cell permeability, but also on free radical- and ROS-scavenging activities. These results indicate that the cell permeability and free radical- and ROS- scavenging activities of antioxidants are major factors affecting the protection of cell membranes against the oxidative damage induced by photosensitization reaction.

• YAKHAK HOEJI
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• v.38 no.4
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• pp.469-475
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• 1994

As the continued studies for Korean cultivated rhubarb, MeOH extract of the leaves was fractionated with ether, ethylacetate, and n-butanol. From the ethyl acetate fraction of MeOH extract, one flavone glycoside, apigenin-8-${\beta}$-D-glucopyranoside(vitexin, $C_{21}H_{20}O_{10}$) and from the n-BuOH fraction of MeOH extract, two flavonol glycosids, kaempferol-3-O-(2,6-di-O-rhamnopyranosyl)-${\beta}$-D-galactopyranoside$(C_{33}H_{40}O_{19})$and quercetin-3-O-rutinoside(rutin, $C_{27}H_{30}O_{16}$) were isolated and identified through the physico-chemical properties and spectroscopic evidences(UV, IR, NMR, Mass) respectively.

• YAKHAK HOEJI
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• v.37 no.4
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• pp.325-330
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• 1993

Four flavonoide glycosides and (-)-Epicatechin were isolated from the aqueous extracts of dried whole part of Lysimachia clethroides Duby(Primulaceae). They were 3-0-Methyl-quercetin-7-0-[$\alpha$-L- rhamnopyranosyl (1-2) glucopyranoside], Quercetin-3-0-$\beta$-D-glucopyranoside, Kaempferol-3-0-$\beta$-D-glucopyranoside, Kaempferol-3-0-[$\alpha$-L-rhamnopyranosyl (1-6)-$\beta$-D-glucopyranoside] and (-)-Epicatechin. 3-0-[$\alpha$-L-rhamnopyranosyl (1-6)-$\beta$-D-glucopyranoside]and (-)-Epicatechin. 3-0-Methyl-quercetin-7-0-[$\alpha$-L-rhamnopyranosyl (1-2)-$\beta$-D-glucopyranoside] and (-)-Epicatechin were first isolated from this plant. Their structures were elucidated by spectral analysis [$^{1}$H-, $^{13}C-$ NMR, $^{1}$H-$^{1}$H-COSY, DEPT-analysis, HMQC(Heteronuclear multiple quantum coherence), FAB-MS].