• Natural Product Sciences
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• v.10 no.5
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• pp.244-247
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• 2004

The inhibitory effects of the leaves of Eucalyptus darylmpleana (Myrtaceae) on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical was examined. The scavenging effect of the ethyl acetate fraction of Eucalyptus darylmpleana leaves on DPPH radical was stronger than the other fractions, and further purified by silica gel and Sephadex LH-20 column chromatography. 3,4-Dihydroxybenzoic acid, gallic acid, quercetin, quercetin $3-O-{\alpha}-_L-rhamnoside$, quercetin $3-O-{\beta}-_D-glucoside$ and quercetin 3-O-rutinoside were isolated and elucidated by spectroscopic data. Among these components, gallic acid and quercetin $3-O-{\alpha}-_L-rhamnoside$ exhibited potent scavenging activities on DPPH radical with $IC_{50}$ values of 6.02 and $5.54\;{\mu}M$, respectively.

• The Korea Journal of Herbology
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• v.24 no.4
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• pp.137-142
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• 2009

Objectives : This study was performed to investigate the antioxidant activities of isolated compounds from the shoot of Aralia elata. Methods : The methanol extract from the shoot of Aralia elata was fractionated into ethyl acetate, n-BuOH and $H_2O$ layers through solvent fractionation. Repeated silica gel, ODS column chromatography of n-BuOH layer afforded four flavonol glycosides. Their antioxidant activity was determined by measuring free radical scavenging activity by DPPH, ABTS and superoxide dismutase (SOD) like activity assay. Results : They were identified as quercetin 3,7-di-O-$\alpha$-rhamnopyranoside (1), quercetin 3-O-$\beta$-D-galactoside-7-O-$\alpha$-L-rhamnoside (2), kaempferol 3-O-$\beta$-glucosyl($1{\rightarrow}2$)-$\alpha$-rhamnoside-7-O-$\alpha$-rhamnoside (3) and quercetin 3-O-$\beta$-glucosyl($1{\rightarrow}2$)-$\alpha$-rhamnoside-7-O-$\beta$-rhamnoside (4) on the basis of spectroscopic data. The result showed that 1 is the most active compound in the DPPH and ABTS radical scavenging test. Conclusions : Isolated Compounds from the shoot of Aralia elata showed anti-oxidative effect.

• Herbal Formula Science
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• v.12 no.1
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• pp.255-262
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• 2004

The inhibitory effect of the aerial parts of Fagopyrum esculentum on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical was examined. The n-butanol fraction from the methanol extract of title plant showed stronger inhibitory effect than other fractions on DPPH radical. Two flavonoids were isolated from n-butanol fraction having the potent activity and elucidated as quercetin-3-O-${\alpha}$-L-rhamnoside and quercetin-3-O-rutinoside on the basis of spectral evidence. The $IC_{50}$ values of these compounds on DPPH radical were 6.56 ${\mu}M$ and 8.37 ${\mu}M$, respectively.

• Natural Product Sciences
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• v.24 no.4
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• pp.272-283
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• 2018

The root-knot nematode, Meloidogyne incognita caused a serious damage to many plants. The phenolic components of the leaves of Schinus terebinthifolius were investigated as potential nematicidal agents for M. incognita. Nine compounds were isolated and characterized as viz., 1,2,3,4,6-pentagalloyl glucose (1), kaempferol-3-O-${\alpha}$-L-rhamnoside (Afzelin) (2), quercetin-3-O-${\alpha}$-L-rhamnoside (Quercetrin) (3), myricetin (4), myricetin-3-O-${\alpha}$-L-rhamnoside (Myricetrin) (5), methylgallate (6), protocatechuic acid (7), quercetin (8), and gallic acid (9) using nuclear magnetic resonance (NMR) spectroscopy. Compound 1 showed pronounced nematicidal activity compared to Oxamyl as a positive control. It showed the lowest eggs-hatchability (34%) and the highest mortality in nematode population (21% after 72 hours of treatment) at a concentration of $200{\mu}g/mL$. It exhibited the best suppressed total nematode population, root galling and number of eggmasses in infected tomato plants. The total carbohydrates and proteins were also significantly induced by 1 with reduction in total phenolics and increase in defense-related proteins. Thus, compound 1 could be a promising, more safe and effective natural nematicidal agent for the control of root-knot nematodes.

• Archives of Pharmacal Research
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• v.27 no.1
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• pp.44-47
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• 2004

Loranthus tanakae Fr. et Sav. (Loranthaceae) is a species of mistletoe, a semiparasitic plant growing on the branches of Quercus and Betula species as host trees. In our ongoing search for bioactive compounds from endemic species in Korea, we have investigated to isolate the chemical constituents responsible for the antitumor effect of the MeOH extract of L. tanakae. The ethyl acetate soluble part of the MeOH extract demonstrated a marginal inhibition on the proliferation of the tumor cell lines such as A549 (non small cell lung), SK-OV-3 (ovary), SK-MEL-2 (melanoma), XF498 (central nerve system), and HCT-15 (colon) in vitro. Thus, the activity-guided isolation procedure upon the ethyl acetate soluble part of the extract has been carried out and finally four flavonoid rhamnopyranosides (1-4) were isolated as active principle. The structures of 1-4 were elucidated by the physicochemical and spectral data as rhamnetin 3-O-$\alpha$-L-rhamnoside (1), quercetin 3-O-$\alpha$-L-rhamnoside (2), rhamnocitrin 3-O-$\alpha$rhamnoside (3), and kaempferol 3-O-$\alpha$-L-rhamnoside (4).

• Korean Journal of Pharmacognosy
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• v.25 no.3
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• pp.199-203
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• 1994

Chemical examination of the leaves of Betula platyphylla var. latifolia has led to the isolation and characterization of five flavonoid glycosides including two C-glucosyl flavonoids. The structures of these compounds were elucidated as myricetin $3-O-{\alpha}-_L-rhamnoside$ (myricitrin), $quercetin-3-O-{\beta}-_D-glucopyranoside$ (isoquercitrin), $quercetin-3-O-{\beta}-_D-glucopyranoside$ (hyperoside), $nalingenin-6-C-{\beta}-_D-glucopyranoside$ (hemiphloin) and $aromadendrin-6-C-{\beta}-_D-glucopyranosidre(6-C-glucosyldihydrokaempferol)$ on the basis of physico-chemical and spectroscopic evidences.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.298.2-298.2
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• 2002

Bioflavonoids are semi-essential food components that are ubiquitously present in nature. It has been reported that flavonoids act as anti-oxidant as well as anti-cancer agents. Quercetin is one of the most widely distributed bioflavonoids in the plant kingdom. The goal of this study was to investigate effects of quercetin analogs extracted from Lindera erythrocarpa, quercetin 3-O-${\alpha}$-arabinofuranoside and quercetin 3-O-${\alpha}$-L -rhamnoside, on oxidatie stress-induced cell death. (omitted)

• Korean Journal of Pharmacognosy
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• v.27 no.3
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• pp.238-245
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• 1996

The activity guided fractionation of $CH_2Cl_2$ soluble part of Platycarya strobilacea leaves(Juglandaceae) has led to the isolation of eight active principles, identified as 5-hydroxy-2-methoxy-1,4-naphthoquinone(1), ursolic acid(2), gallic acid(3), 4,8-dihydroxynaphthalene $1-O-{\beta}-_D-glucoside(4)$, eriodictyol(5), quercetin $3-O-(2'-O-galloyl)-{\beta}-_D-glucoside(6)$. quercetin $3-O-(2'-O-galloyl)-{\beta}-_D-galactoside(7)$ and quercetin $3-O-{\alpha}-_L-rhamnoside(8)$ by the means of chemical and spectral evidence, respectively.

• Natural Product Sciences
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• v.23 no.2
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• pp.139-145
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• 2017

Seven flavonoid compounds, kaempferol (1), quercetin (2), quercetin-3-O-${\beta}$-D-glucopyranoside (3), kaempferol-3-O-${\beta}$-D-glucopyranoside (4), kaempferol-3-O-${\alpha}$-L-rhamnoside (5), quercetin-3-O-sophoroside (6) and quercetin-3-O-rutinoside (7), were isolated from the methanolic extract of leaves of Kalanchoe prolifera. Compounds 1-7 were isolated for first time from this plant. These compounds were evaluated their cytotoxic activity against P-388 murine leukimia cells in vitro. Among those compounds kaempferol (1) and quercetin (2) showed strongest cytotoxic activity with $IC_{50}$ values of $4.45{\pm}0.05$ and $6.28{\pm}0.02{\mu}g/mL$, respectively.

• Natural Product Sciences
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• v.11 no.2
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• pp.75-78
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• 2005

A new acetophenone named rumexin $(3-hydroxy-5-methyl-4-O-{\beta}-D-glucopyranosyl\;acetophenone)$ was isolated from methanolic extract of Rumex aquatica together with eight known compounds, $quercetin-3-O-{\beta}-D-glucuropyranoside$, $musizin-8-O-{\beta}-D-glucopyranoside$, $quercetin-3-O-{\alpha}-L-rhamnoside$, $emodin-8-O-{\beta}- D-glucopyranoside$, caffeic acid, $1-O-caffeoyl-{\beta}-D-glucopyranoside$, 1-methyl caffeic acid, $kaempferol-3-O-{\beta}-D-glucuropyranoside$. All of the above compounds were isolated from Rumex aquatica for the first time, and structures of compounds were established by spectroscopic means.