• 한국식품영양과학회지
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• 제25권1호
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• pp.76-79
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• 1996

생강나무 (Libdera obtusiloba BL.)의 페놀성 화합물들을 분리하기 위하여 잎고 줄기의 MeOH 엑스로부터 계통 분획한 EtOAc 분획물은 silica gel column chro-matography로 분리하여 2종의 화합물을 얻었다. IR, UV,$^1H-NMR$, $^13C-NMR$ 등의 분석을 행하여 화학구조를 밝힌 결과 이들 화합물의 화학구조는 잎에서 $quer-cetin-3-O-\alpha-L-rhamnopyranoside(quercitrin),$ 줄기에서는 quercetin $3-O-\beta-D-galactoyranoside(hyperoside)로$ 각각 결정하였다. 이 화합물들은 생강나무에서 처음으로 분리하였다.

• 대한화장품학회지
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• 제16권1호
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• pp.1-17
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• 1990

The major flavonoid component of Ginseng leaf is trifolin, a glycoside of kaempferol. To evaluate the antioxidative properties of trifolin and kaempferol on cellular membranes, we compared them with the other flavonoids through the 102-Induced photohemolysis of rabbit erythrocytes. All the flavonoid aglycones including kaempferol, quercetin and baicalein protected effectively the cells from the 102-caused damage in a dose- dependent manner, by scavenging 102 and free radicals in the cellular membranes. The solubilization of the flavonoid aglycones into micelles or erythrocyte membranes was deduced from spectro-photometric and microscopic observations. The flavonoid glycosides were not protective or less protective than their corresponding aglycones, and trifolin was the only glycoside that exhibited a solubilization into the membranes and a significant protection against the photohemolysis. We also tested some phenolic compounds contained in Ginseng, and found that they did not prevent the photohemolysis so effectively as kaempferol or trifolin.

• 생명과학회지
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• 제29권12호
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• pp.1371-1377
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• 2019

뇌에서 과량의 reactive oxygen species (ROS) 생성에 의해 유발되는 산화적 스트레스는 알츠하이머 질환과 같은 신경퇴행성 질환의 원인으로 알려져 있다. 본 연구에서는 kaempferol, kaempferol-3-O-glucoside, quercetin, quercetin-3-β-D-glucoside와 같은 flavonoid와 그 배당체의 H₂O₂ 유도 산화적 스트레스에 대한 C6 신경교세포보호 효과를 확인하였다. H₂O₂만을 처리한 control군은 아무것도 처리하지 않은 normal군에 비해 세포 생존율 감소와 ROS 생성 증가를 통해 C6 신경교세포의 산화적 손상이 유도되었음을 확인하였다. 반면 4가지 flavonoid를 각각 처리한 군의 경우, H₂O₂를 처리한 control군에 비해 세포 생존율 증가와 ROS 생성 감소를 통해 산화적 손상 억제를 통한 신경교세포 보호 효과를 확인하였다. Flavonoid의 신경교세포 보호 작용 메커니즘을 규명하기 위해, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and interleukine (IL)-1β 등의 염증 관련 단백질 발현을 측정하였다. H₂O₂를 처리한 control군은 normal군에 비해 iNOS, COX-2, IL-1β 단백질 발현 증가와 IκB-α 발현 감소를 통해 신경교세포의 산화적 손상으로 인한 염증 반응을 확인하였다. 반면, 4가지 flavonoid를 각각 처리한 군의 경우 iNOS, COX-2, IL-1β 단백질 발현 감소와 IκB-α 발현 증가를 나타내어, 염증 반응 개선을 통한 신경교세포 보호 효과를 확인하였다. 특히, quercetin과 그 배당체인 quercetin-3-β-D-glucoside를 처리한 군은 kaempferol과 그 배당체인 kaempferol-3-O-glucoside를 처리한 군에 비해 우수한 신경교세포 보호 효과를 나타내었다. 본 연구는 4가지 flavonoid가 신경교세포에서 산화적 스트레스 억제를 통해 신경퇴행성 질환을 예방 및 치료할 수 있을 것으로 사료된다.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 1990년도 Proceedings of International Symposium on Korean Ginseng, 1990, Seoul, Korea
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• pp.49-57
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• 1990

It has been well known that extended exposure to reactive oxygens causes severe damage to susceptible biomolecules. In this study, the effects of flavonoids including trifling and kaempferol from Ginseng leaves on single oxygen induced photohemolysis of erythrocytes and free radical scavenging activities were investigated . Each flavonoid aglycone (5-50UM) such as kaempferol, quercetin or baicalein exhibited a high protective effect against the photohemolysis. They protected the cells by scavenging 102 and free radicals. Although the free radical scavenging activities of the flavonoid glycosides were not much lower than those of their corresponding aglycones, their insolubility into lipid bilayers of membrane made them less effective in preventing the photohemolysis induced by 1O2. The 102 and free radical scavenging activities of flavonoids were estimated by the decomposition of the flavonoid by 1O2 and the bleaching of free radicals by the flavonoid, respectively. The solubilization of the flavonoid into micelle or erythrocytes was deduced from spectrophotometric and microscopic observations. The cooperation of L-ascorbic acid and a flavonoid, and a possible involvement of lipoxygenase or cyclooxygenase in the photohemolysis mechanism were discussed. Keywords Panax ginseng C.A Meyer, ginseng leaves, flavonoids, singe1 oxygen, Photohemolysis.

• Journal of Ginseng Research
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• 제14권2호
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• pp.191-199
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• 1990

It has been well known that extended exposure to reactive oxygens causes severe damage to susceptible biomolecules. In this study, the effects of flavonoids including trifolin and kaempferol from Ginseng leaves on singlet oxygen induced photohemolysis of erythrocytes and free radical scavenging activities were investigated. Each flavonoid aglycone (5-50$\mu$M) such as kaempferol, quercetin or baicalein exhibited a high protective effect against the photohemolysis. They protected the cells by scavenging $^1O_2$ and free radicals Although the free radical scavenging activities of the flavonoid glycosides were not much lower than those of their corresponding aglycones, their insolubility into lipid bilayers of membrane made them less effective in preventing the photohemolysis induced by $^1O_2$. The $^1O_2$ and free radical scavenging activities of flavonoids were estimated by the decomposition of the flavonoid by $^1O_2$ and the bleaching of free radicals by the flavonoid, respectively. The solubilization of the flavonoid into micells or erythrocytes was deduced from spectrophotometric and microscopic observations. The cooperation of L-ascorbic acid and a flavonoid, and a possible involvement of lipoxygenase or cyclooxygenase in the photohemolysis mechanism were discussed.

• Biomolecules & Therapeutics
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• 제15권1호
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• pp.46-51
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• 2007

Bioassay-directed chromatographic fractionation of an ethyl acetate extract from leaves of sweet potato (Ipomoea batatas L.) afforded six quinic acid derivatives: 3,5-epi-dicaffeoylquinic acid (1), 3,5-dicaffeoylquinic acid (2), methyl 3,5-O-dicaffeoylquinate (3), methyl 3,4-dicaffeoylquinate (4), methyl 4,5-dicaffeoylquinic acid (5),4,5-dicaffeoylquinate (6), and two phenolic compounds: caffeic acid (7) and caffeic acid methyl ester (8) together with three flavonoids: quercetin 3-O-${\beta}$-D-glucopyranoside (9), quercetin 3-O-${\beta}$-D-glucopyranoside, isoquercitrin (10) and kaempferol 3-O-${\beta}$-D-glucopyranoside (11). The structures of these compounds were elucidated by the aid of spectroscopic methods. These compounds were assessed for antioxidant activities using three different cell-free bioassay systems. All isolates except 11 showed potent DPPH and superoxide anion radicals scavenging, and lipid peroxidation inhibitory activities. 3,5-epi-DCQA (1) and methyl quinates (3-5) along with flavonoide 9 were isolated for the first time from this plant.

• 생약학회지
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• 제42권2호
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• pp.138-143
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• 2011

A high performance liquid chromatography (HPLC) method was developed for simultaneous determination of two major flavonoid glycosides (poncirin and nanringin) in Poncirus trifoliata Raf. by different harvesting times and locations for two years. A SunFire $C_{18}$ column (4.6 mm${\times}$250 mm, 5 ${\mu}M$) was used at $40^{\circ}C$ for the determination of poncirin and naringin. The mobile phase using gradient flow consisted of two solvent systems. Solvent A was 1.0% (v/v) aqueous acetic acid and solvent B was acetonitrile with 1.0% (v/v) acetic acid. Flow rate was 1.0 mL/min and injection volume was 10 ${\mu}l$. The chromatogram was monitored by photodiode array (PDA) detection at 280 nm for the identification of two flavonoid glycosides in P. trifoliata. The contents of the two components in P. trifoliata ranged from 0.32~13.02%.

• 약학회지
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• 제33권2호
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• pp.124-128
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• 1989

The drug consists of the dried entire plant of Viola diamantica (family Violaceae). It is used for the treatment of acute pyogenic diseases such as boil and carbuncles; also as tumor, high fever, tuberculosis and astringent hemostatic. Two flavonol glycosides have been isolated from the aerial parts of Viola diamantica and could be identifed as kaempferol 7-rhamnoside and kaempferol 3,7-dirhamnoside (bright yellow needle crystal, mp $225^{\circ}$, $C_{27}\;H_{30}\;O_4\;4H_2O$). Kaempferol 7-rhamnoside and kaempferol 3,7-dirhamnoside were first isolated from Viola diamantica.

• Journal of Microbiology and Biotechnology
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• 제28권11호
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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.

• Biomolecules & Therapeutics
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• 제24권4호
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• pp.410-417
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• 2016

Quercetin is a flavonoid usually found in fruits and vegetables. Aside from its antioxidative effects, quercetin, like other flavonoids, has a various neuropharmacological actions. Quercetin-3-O-rhamnoside (Rham1), quercetin-3-O-rutinoside (Rutin), and quercetin-3-(2(G)-rhamnosylrutinoside (Rham2) are mono-, di-, and tri-glycosylated forms of quercetin, respectively. In a previous study, we showed that quercetin can enhance ${\alpha}7$ nicotinic acetylcholine receptor (${\alpha}7$ nAChR)-mediated ion currents. However, the role of the carbohydrates attached to quercetin in the regulation of ${\alpha}7$ nAChR channel activity has not been determined. In the present study, we investigated the effects of quercetin glycosides on the acetylcholine induced peak inward current ($I_{ACh}$) in Xenopus oocytes expressing the ${\alpha}7$ nAChR. $I_{ACh}$ was measured with a two-electrode voltage clamp technique. In oocytes injected with ${\alpha}7$ nAChR copy RNA, quercetin enhanced $I_{ACh}$, whereas quercetin glycosides inhibited $I_{ACh}$. Quercetin glycosides mediated an inhibition of $I_{ACh}$, which increased when they were pre-applied and the inhibitory effects were concentration dependent. The order of $I_{ACh}$ inhibition by quercetin glycosides was Rutin${\geq}$Rham1>Rham2. Quercetin glycosides-mediated $I_{ACh}$ enhancement was not affected by ACh concentration and appeared voltage-independent. Furthermore, quercetin-mediated $I_{ACh}$ inhibition can be attenuated when quercetin is co-applied with Rham1 and Rutin, indicating that quercetin glycosides could interfere with quercetin-mediated ${\alpha}7$ nAChR regulation and that the number of carbohydrates in the quercetin glycoside plays a key role in the interruption of quercetin action. These results show that quercetin and quercetin glycosides regulate the ${\alpha}7$ nAChR in a differential manner.