• Journal of Microbiology and Biotechnology
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• v.28 no.11
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• pp.1859-1864
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• 2018

Synthesis of flavonoid glycoside is difficult due to diverse hydroxy groups in flavonoids and sugars. As such, enzymatic synthesis or biotransformation is an approach to solve this problem. In this report, we used stepwise biotransformation to synthesize two quercetin bisglycosides (quercetin 3-O-glucuronic acid 7-O-rhamnoside [Q-GR] and quercetin 3-O-arabinose 7-O-rhamnoside [Q-AR]) because quercetin O-rhamnosides contain antiviral activity. Two sequential enzymatic reactions were required to synthesize these flavonoid glycosides. We first synthesized quercetin 3-O-glucuronic acid [Q-G], and quercetin 3-O-arabinose [Q-A] from quercetin using E. coli harboring specific uridine diphopsphate glycosyltransferase (UGT) and genes for UDP-glucuronic acid and UDP-arabinose, respectively. With each quercetin 3-O-glycoside, rhamnosylation using E. coli harboring UGT and the gene for UDP-rhamnose was conducted. This approach resulted in the production of 44.8 mg/l Q-GR and 45.1 mg/l Q-AR. This stepwise synthesis could be applicable to synthesize various natural product derivatives in case that the final yield of product was low due to the multistep reaction in one cell or when sequential synthesis is necessary in order to reduce the synthesis of byproducts.

• 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.

• Journal of Microbiology and Biotechnology
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• v.9 no.5
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• pp.661-667
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• 1999

The effect of fungal elicitor and heavy metal salts on the production of flavonol glycosides in cell cultures of Ginkgo biloba was investigated. Among the fungi tested, Trichoderma longibrachiatum ATCC 52326 was found to be the most efficient in the production of flavonol glycosides. Kaempferol production from the elicited callus increased ten-fold as compared to the unelicited callus, while quercetin concentration of elicited cells was nine-fold higher than that of uneliceited cells in suspension cultures. The maximum quercetin concentration of 0.362㎎/l was obtained in 1.25㎎/l of the homogenate elicitor. Among the heavy metal salts tested, CuSO₄ showed a significant effect on quercetin accumulation, reaching to the concentration of 0.526 ㎎/l. Quercetin concentration increased to a maximum of l2-fold in response to CuSO₄ treatment as compared to that of untreated cells. The phenylalanine ammonia-lyase (PAL) activity and flavonol glycosides production simultaneously increased for 5 days of culture after fungal elicitor feeding, and their contents showed the same proportional patterns during the culture period. In contrast, PAL activity of cell cultures treated with CuSO₄ was almost constant during the culture period, although quercetin production increased remarkably.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.4
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• pp.682-686
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• 1998

To use onion(Allium cepa L.) residue as raw materials of food products, contents and stability of quercetin-related substance in onion were investigated. The amount of quercetin-related substance of onion was richer in the inedible portion(317.99mg%) than the edible protion(4.10mg%). Total quercetin-related substances of juice and residue from fresh onions were 2.26mg% and 1.57mg%, respectively, but they were changed to 1.50mg% and 2.96mg% by heating at 8$0^{\circ}C$ for 10min. Quercetin was found to be stable at 20$0^{\circ}C$ for 60 min, but it was unstable to light. When it was illuminated with 30W, the content was decreased and reached to 80~85% of the original content after 48 hours. Quercetin was not affected by pH, but quercitrin and rutin were unstable below pH 5.

• YAKHAK HOEJI
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• v.39 no.3
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• pp.289-296
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• 1995

For the investigation of medicinal resources the studies were carried out to evaluated the pharmaco-constituents in the Leaves of Parthenocissus tricuspidata(Vitaceae), of which leaves have been used in Korea as folk remedies for the treatments of arthritis, jaundice, toothache, neuralgia, and etc. From 1-butanol fraction of the MeOH extract, Compound I ($C_{21}H_{18}O_{13}$, Quercetin-3-O-$\beta$-D-glucuronopyranoside), Compound II ($C_{21}H_{20}O_{12}$, Quercetin-3-O-$\beta$-D-glucopyranoside) and Compound III ($C_{25}H_{28}O_{12}$, Quercetin-3-O-(6"-n-butyl)-$\beta$-D-glucuronopyranoside) were isolated by column chromatographic separation using Sephadex LH-20 and ODS gel. Their structures were elucidated through instrumental analyses, such as $^{1}H$-NMR, $^{13}C$-NMR, IR, UV, El-Mass, FAB-Mass and GC. Especially compound III was Flavonol glycoside and named parthenosin.

• Journal of Microbiology and Biotechnology
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• v.8 no.3
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• pp.237-244
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• 1998

A study was carried out to elucidate the relation between the production of flavonol glycosides and the change of phenylalanine ammonia-lyase activity in cell suspension cultures of Ginkgo biloba by the unassisted and synergistic effects of various factors. The quercetin production showed a mixed-growth-associated pattern in cell suspension cultures. Fluorescent light and UV radiation increased phenylalanine ammonia-lyase (PAL) activity, and resulted in the increase of the production of quercetin and kaempferol ten- and four-fold, respectively, as compared to that obtained in the normal culture condition. The cell growth of Ginkgo biloba was enhanced .at higher temperatures whereas the quercetin production was at its maximum at low temperatures. Moreover, the quercetin production was increased by temperature change during the culture period. In particular, the quercetin production was at the highest level when the culture temperature was elevated from $10^{\circ}C\;to\;30^{\circ}C$. The addition of phenylalanine as a precursor in the culture medium stimulated an 8-fold increase in the production of quercetin; the addition of naringenin caused a l0-fold increase. The quercetin production was also greatly increased by feeding enzyme cofactors such as 2-ketoglutarate and ascorbic acid in the culture medium, but specific PAL activity was not increased except with phenylalanine feeding. The synergistic effect of UV radiation and naringenin feeding was observed, resulting in the increase of flavonol glycoside production at a rate higher than in any other case investigated.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.3
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• pp.385-389
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• 2014

Flavonols as a major kind of plant secondary metabolites are known for health-promoting compounds in onions (Allium cepa L.). The objectives of this study are to determine profiles of flavonol glycosides in different 75 onion accessions. A total of five flavonols (quercetin 3,4'-diglucoside, Q34'diG; quercetin 3-glucoside, Q3G; quercetin 4'-glucoside, Q4'G; isorhamnetin 4'-glucoside, I4'G; quercetin, Q) were identified from onion accessions. In positive ion mode using LC-ESI-MS, individual flavonols were confirmed from one and two glycosylation binding with aglycone such as quercetin and isorhamnetin. Total flavonol contents were distributed in white onion (range of 0.18-6.47 mg/g DW) and purple onion accessions (range of 2.39-6.47 mg/g), respectively. The mean of flavonol contents in purple onion (4.41 mg/g) showed 1.4-fold higher than white onion (3.23 mg/g). The Q34'diG and Q4'G were considered as the major compounds of flavonol glycosides in onion accessions.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.461-463
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• 2010

• Archives of Pharmacal Research
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• v.11 no.2
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• pp.166-168
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• 1988

The effects of aglycones moring and quercetin and their corresponding glycosides quercitrin and rutin were studied on the blood glucose levels of rats. Quercetin and quercetrin caused hypoglycaemia in rats while rutin and morin showed almost no difference. Quercetin, which showed 50% pronounced hypoglycaemic effects, reduced significantly the blood glucose level of alloxan diabetic rats.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.186-186
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• 1998

Persicaria lapathifolia Gray (Polygonaceae) is a common weed in Korea. This plant and other Persicaria species including P. orientale and P. pubescens have been used as an analgesic and stomachic as well as for the treatment of rheumatoid arthritis and malaria. During the screening program of plant extracts, MeOH extract of P. scabrum showed anticomplement activity and the MeOH extract was partitioned with hexane, chloroform, ethyl acetate, and buthanol. EtOAc fraction showed strong activity and activity guided separation yielded eight flavonoids. Two known galloylated and a novel ferulloylated flavonoid glycosides showed strong anticomplement activity. Other flavonoid glycosides, kaempferol 3-O-${\alpha}$-$\sub$L/-arabinopyranoside, kaempferol 3-O-${\beta}$-$\sub$D/-glucopyranoside, kaempferol 3-O-${\beta}$-$\sub$D/-galactopyranoside, quercetin 3-O-${\alpha}$-$\sub$L/-arabinopyranoside, quercetin 3-O-${\beta}$-$\sub$D/-glucopyranoside, quercetin O-${\beta}$-$\sub$D/-galactopyranoside did not showed anicomplement activity.