• Korean Journal of Agricultural Science
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• v.44 no.1
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• pp.104-113
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• 2017

Anthocyanins contained in Rhododendron schlippenbachii (royal azalea) are expressed in a variety of colors and affect flower colors. R. schlippenbachii flowers of seven colors (white, red group: pink, deep pink, red, purple group: light purple, purple, deep purple) were collected from the garden around KT&G building in the college of agriculture and life science. Seven types of anthocyanins [cyanidin 3-O-diglucoside, cyanidin 3-O-arabinoside-5-O-glucoside, cyanidin 3-O-galactoside, peonidin 3-O-arabinoside-5-O-glucoside, cyanidin 3-O-glucoside, cyanidin 3-O-(6"-O-malonyl) arabinoside, cyanidin 3-O-(6"-O-coumaroyl) glucoside] turned out to be from the cyanidin and peonidin series in R. schlippenbachii flowers. Also, seven types of flavonols [azaleatin 3-O-glucoside, azaleatin 3-O-arabinoside, azaleatin 3-O-rhamnoside, quercetin 3-O-galacatoside, quercetin 3-O-glucoside, quercetin 3-O-arabinoside, quercetin 3-O-rhamnoside] were identified in R. schlippenbachii flowers. Total anthocyanin amounts decreased in R. schlippenbachii flowers in the following order: 'deep pink' (8.07) > 'red' (6.37) > 'pink' (5.35) > 'deep purple' (0.78) > 'purple' (0.43) > 'light purple' ($0.22mg{\cdot}g^{-1}$ dry weight, DW) > 'white' (not detected). Total flavonol amounts decreased in the following order: 'pink' (97.78) > 'deep pink' (63.79) > 'deep purple' (61.98) > 'white' (57.58) > 'light purple' (47.06) > 'purple' (46.76) > 'red' ($7.60mg{\cdot}g^{-1}$ dry weight, DW). This study provided the quantitative and qualitative information for the variation of anthocyanin and flavonol compounds in R. schlippenbachii flowers. Furthermore, this information can contribute to the identification of anthocyanin and flavonol compounds in other Rhododendron flowers.

• 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.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.981-987
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• 2011

The anomalous spectroscopic properties of quercetin-3-O-rhamnoside (QCRM) and quercetin-3-O-rutinoside (QCRT) in AOT reverse micelle were studied. The excited state intramolecular proton transfer (ESIPT) occurs through the strong hydrogen bond between the -OH at position 5 and the carbonyl oxygen. Because the ESIPT can only happens in the $S_1$ state and the Franck-Condon factor involved in the $S_2\;{\rightarrow}\;S_1$ internal conversion is small, the $S_2\;{\rightarrow}\;S_o$ emission alone appears. Because the molecular planarity is improved at the interior of the micelle, the excited state intramolecular charge transfer in the $S_1$ state is extended, and the excited state is more tolerable for any quenching effects in the micelle. Therefore, an $S_1\;{\rightarrow}\;S_o$ emission was newly discovered under this micelle microenvironment. For the $S_2\;{\rightarrow}\;S_o$ emission, the quantum yields increase but the quantum yield of the $S_1\;{\rightarrow}\;S_o$ emission approximately decreases as the water concentration in the micelle increases.

• 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.

• Journal of Applied Biological Chemistry
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• v.54 no.1
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• pp.47-50
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• 2011

To develop a new natural whitening agent, we investigated the tyrosinase inhibitory effects of Persicaria tinctoria Flower extracts (PTFE). PTFE showed inhibitory activity on mushroom tyrosinase with the $IC_{50}$ values of $70.8{\pm}2.2{\mu}g/mL$. We purified two active compounds from PTFE by LH-20 column chromatography and prep-high performance liquid chromatography (HPLC) and identified as quercetin-3-O-rhamnoside (Q3R) and myricetin-3-O-rhamnoside (M3R) by $^1H$nuclear magnetic resonance (NMR) and liquid chromatography-mass spectrometry (LC-MS) analysis. Q3R and M3R showed tyrosinase inhibitory activities with the $IC_{50}$ values of $47.0{\pm}0.1{\mu}g/mL$ and $150.5{\pm}1.6{\mu}g/mL$, respectively. These results suggest that PTFE and its active compounds reduced melanin formation by the inhibition of tyrosinase activity. Thus, P. tinctoria flower extracts may be a candidate for cosmetic use.

• Natural Product Sciences
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• v.9 no.4
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• pp.245-248
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• 2003

A phytochemical investigation on the methanolic extract of Cosmos caudatus has led to the isolation of quercetin $3-O-{\beta}-D-arabinofuranoside$ (1), quercetin $3-O-{\beta}-D-rhamnoside$ (2), quercetin $3-O-{\alpha]-D-glucoside$ (3) and quercetin (4). These compounds were shown to be the antioxidative constituents of the plant when evaluated using the ferric thiocyanate (FTC) and thiobarbituric acid (TBA), and radical scavengers based on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assays.

• 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.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.

• 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)

• 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.