• Korean Journal of Pharmacognosy
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• v.31 no.4
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• pp.430-433
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• 2000

Five compounds have been isolated from the stem of Caesalpinia japonica. On the basis of spectral evidences, the structures of these compounds were identified as 4',7-dihydroxyflavone, 3,4',7-trihydroxyflavone, cathechin, 3',4',7-trihydroxyflavone and 2',3,4',5,6,7-hexahydroxyflavone.

• Archives of Pharmacal Research
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• v.4 no.2
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• pp.129-131
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• 1981

From the steambark of Albizzia julibrissin, 3', 4' 7-trihydroxyflavone and .alpha.-spinasteryl-D-glucoside were isolated.

• Natural Product Sciences
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• v.16 no.4
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• pp.217-222
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• 2010

A phytochemical investigation of the ethanolic extract of Erythrina caffra flowers from an Egyptian origin yielded three C-flavonoidal glycosides; 5,7,4'-trihydroxyflavone-8-C-$\beta$-D-glucopyranoside (vitexin) (1), 5,7,4'-trihydroxyflavone-6-C-$\beta$-D-glucopyranosyl-(1 $\rightarrow$ 2)-$\beta$-D-glucopyranoside (isovitexin-2"-$\beta$-D-glucopyranoside) (2), 5, 7, 4'-trihydroxyflavone-6, 8-di-C-$\beta$-D-glucopyranoside (vicenin-2) (3) and one O-flavonoidal glycoside; kaempferol-3-O-$\beta$-D.glucopyranosyl) (1 $\rightarrow$ 2)-$\beta$-D-glucopyranoside (4). The structures of the isolated compounds (1 - 4) were elucidated using different spectral techniques (UV, 1D and 2D NMR and HRESIMS). This is the first report for the isolation of flavonoidal glycosides from Erythrina caffra. The antibacterial, antifungal, antimalarial, and antileishmanial activities of the isolates were evaluated. In addition, the cytotoxic activity of the ethanolic extract and the main fractions were tested using brine shrimp bioassay.

• Archives of Pharmacal Research
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• v.26 no.6
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• pp.458-462
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• 2003

The antioxidant activity of the stem bark from Albizzia julibrissin was evaluated for its potential to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, to inhibit the generation of the hydroxyl radical ($\cdot OH$), total reactive oxygen species (ROS) and to scavenge authentic peroxynitrites ($ONOO^{-}$). The methanol extract of A. julibrissin exhibited strong antioxidant activity in the tested model systems. Therefore, it was further fractionated using several solvents. The antioxidant activity of the individual fractions were in the order of ethyl acetate (EtOAc) ＞ n-butanol (n-BuOH) ＞ dichloromethane ($CH_2 CI-2$) ＞ and water ($H_2O$). The ethyl acetate soluble fraction, which exhibited strong antioxidant activity, was further purified by repeated silicagel, Sephadex LH-20 and RP-18 gel column chromatography. Sulfuretin (1) and 3 ,4 ,7-trihydroxyflavone (2) were isolated as the active principles. Compounds 1 and 2 exhibited good activity in all tested model systems. Compound 1 exhibited five times more inhibitory activity on the total ROS than Trolox. Compound 2 showed six times stronger DPPH radical scavenging activity than L-ascorbic acid. These results show the possible antioxidant activity of the A. julibrissin crude extract and its major constituents.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.578-586
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• 2008

Phytochemicals study from the leaves of soybean [Glycine max (L.) Merr.], one of Korean edible plant materials were investigated through various chromatographic procedures. The methanolic leaves extracts of soybean yielded 16 phytochemicals, including 5 isoflavones 1-5, 3 flavones 6-8, 1 flavonol 9, 2 pterocarpans 10 and 11, 2 phenolic compounds 12 and 13, 2 phytosterols 14 and 15, and 1 sugar alcohol 16. The structures were fully characterized by analysis of physical and spectral data and were defined clearly as 4,5,7-trihydroxyisoflavone (1), 4,5,7-trihydroxyisoflavone-7-O-$\beta$-D-glucopyranoside (2), 4,7-dihydroxy-6-methoxyisoflavone (3), 4,7-dihydroxyisoflavone (4), 4,7-dihydroxyisoflavone-7-O-$\beta$-D-glucopyranoside (5), 5,7,4'-trihydroxyflavone (6), 3',4',5,7-tetrahydroxyflavone (7), 3',4',5-trihydroxyflavone-7-O-$\beta$-D-glucopyranoside (8), 3,4',5,7-tetrahydroxyflavonol (9), coumestrol (10), glyceofuran (11), 4-hydroxybenzoic acid (12), methyl-4-hydroxybenzoate (13), soyasapogenol B (14), stigmasterol (15), and D-mannitol (16), respectively. Among them, phytochemicals 7-16 were reported for the first time on the isolation and confirmation from the leaves of this species. These results suggest that the leaves extracts of soybean may possess possible health related benefits to human due to the isolated phytochemicals 1-16 which have been well known potential effects on various chronic diseases.

• YAKHAK HOEJI
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• v.32 no.2
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• pp.125-128
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• 1988

Geranylation of some synthetic and natural flavones have yielded cytotoxic products against L1210 coll; 5,2´-dihydroxy-6,7,8-trimethoxy-6´-geranyloxyflavone 4$(8.5{\mu}g/ml)$, 5,6-dihydroxy-7-gerenyloxyflavone 9$(2.3{\mu}g/ml)$. 2 has showed the same range of cytotoxicity as the starting material, 5,2´-dihydroxy-6,7,8-trimethoxy-6´-benzyloxyflavone$(17.0{\mu}g/ml)$. The cytotoxicity of 4 was lower than its starting substance, 5,2´,6´-trihydroxy-6,7,8-trimethoxyflavone $(4.5{\mu}g/ml)$. On geranylating 5,6,7-trihydroxyflavone(baicalein, $15.0{\mu}g/ml$) the cytotoxic activity has been strongly potentiated($2.3{\mu}g/ml$ of 9). The presence of at least a free hydroxy group in B-ring of Skullkapflavone II-type flavones. was essential for a high activity. A larger RD-group than methoxy in the B-ring has weakened the activity. The cytotoxicities of baicalein series could not be correlated to their structures.

• Journal of Life Science
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• v.19 no.8
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• pp.1009-1015
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• 2009

The beneficial use of sedatives is often required for medically ill patients. This study examined the effect of plant flavonoids and diazepam peripheral-type benzodiazepine receptor (PBR) activation and glucose utilization in breast cancer cells, along with their interactions. In estrogen receptor negative MDA-MB-231 cells, the anti-proliferative activity of fisetin (3,7,3',4'-tetrahydroxyflavone) and diazepam was more prominent than in estrogen receptor positive MCF-7 cells. Unlike PBR ligands, treatment with $10^{-6}$ M concentration of diazepam for 3 days exhibited anti-proliferative effects, while similar to apigenin (4',5,7-Trihydroxyflavone) and fisetin, diazepam hardly affected the PBR mRNA expression by MDA-MB-231 cells. Treatment with $10^{-6}$ M concentration of flavonoids and diazepam for 3 days inhibited the glucose utilization of MDA-MB-231 cells. Treatment with $10^{-6}$ M concentration of flavonoids and diazepam for 6 days showed increased cytotoxicity and reduced the PBR mRNA expression of the MDA-MB-231 cells. Apigenin enhanced diazepam-induced anti-proliferative effects on the MDA-MB-231 cells as well. All together, this study showed the in vitro anti-proliferative activity of flavonoids and diazepam on MDA-MB-231 breast cancer cells, plus additive enhancements. In conclusion, this study provides experimental basis for advanced trials in the future.

• Bulletin of the Korean Chemical Society
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• v.35 no.11
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• pp.3219-3223
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• 2014

Ochnaflavone, a naturally occurring biflavonoid composed of two units of apigenin (5,7,4'-trihydroxyflavone) joined via a C-O-C linkage, was first synthesized and evaluated its inhibitory activity on $PGE_2$ production. Total synthesis was accomplished through modified Ullmann diaryl ether formation as a key step. Coupling reactions of 4'-halogenoflavones and 3'-hydroxy-5,7,4'-trimethoxyflavone were explored in diverse reaction conditions. The reaction of 4'-fluoro-5,7-dimethoxyflavone (2c) and 3'-hydroxy-5,7,4'-trimethoxyflavone (2d) in N,N-dimethylacetamide gave the coupled compound 3 in 58% yield. Synthetic ochnaflavone strongly inhibited PGE2 production ($IC_{50}=1.08{\mu}M$) from LPS-activated RAW 264.7 cells, which was due to reduced expression of COX-2. On the contrary, the inhibition mechanism of wogonin was somewhat different from that of ochnaflavone although wogonin, a natural occurring anti-inflammatory flavonoid, showed strong inhibitory activity of $PGE_2$ production ($IC_{50}=0.52{\mu}M$), and seems to be COX-2 enzyme inhibition. Our concise total synthesis of ochnaflavone enable us to provide sufficient quantities of material for advanced biological studies as well as to efficiently prepare derivatives for structure-activity relationship study.

• Archives of Pharmacal Research
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• v.18 no.6
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• pp.415-422
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• 1995

Twenty-four flavones were synthesized with various hydroxyl and/or methoxyl groups on A and B rings. Their antimutagenic properties were evaluated against ben:w(a)pyrene (BaP) and a pool of mutagenic urine concentrate (U) using a modified liquid incubation method of Ames test. The tester strain was Salmonella typhimurium TA98+S9 Mix. The antimutagenic activities were calculated by non linear regression analysis and the doses of flavones (in nmoles) required for a 50% reduction of induced revertants with BaP and U were defined as the inhibition doses (TEX>$ID_{508}{\;}and{\;}ID_{508}$ respectively). Seventeen flavones possessed significant antimutagenic activity against BaP. $ID_{508}$ ranged from 15.1 nmoles (F22) to 1000.6 nmoles (F13). Eighteen f1avones showed significant antimutagenic activity against U. $ID_{50U}$ ranged from 23.5 nmoles (F22) to 354.6 nmoles (F3). The 2',3',4'-trihydroxyflavone (F22, $ID_{508}=15.1$ nmoles, $ID_{50U}=23.5$ nmoles) and the 2',3',4',7-tetrahydroxyflavone (F20, $ID_{508}=37.8$ nmoles; $ID_{50U}=62.3$ nmoles) had antimutagenic activities similar to those of chlorophyllin ($ID_{508}=19.6$ nmoles and $ID_{50U}=44.2$ nmoles) and were evaluated against B(alP 7,8-dihydrodiol-9,10-epoxide. Against this last mutagen, the flavones which included three OH in B ring showed the highest activity and this property seemed independent of the substituent groups on A ring.

• Biomolecules & Therapeutics
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• v.25 no.4
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• pp.427-433
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• 2017

Previously, we demonstrated that galangin (3,5,7-trihydroxyflavone) protects human keratinocytes against ultraviolet B (UVB)-induced oxidative damage. In this study, we investigated the effect of galangin on induction of antioxidant enzymes involved in synthesis of reduced glutathione (GSH), and investigated the associated upstream signaling cascades. By activating nuclear factor-erythroid 2-related factor (Nrf2), galangin treatment significantly increased expression of glutamate-cysteine ligase catalytic subunit (GCLC) and glutathione synthetase (GSS). This activation of Nrf2 depended on extracellular signal-regulated kinases (ERKs) and protein kinase B (AKT) signaling. Inhibition of GSH in galangin-treated cells attenuated the protective effect of galangin against the deleterious effects of UVB. Our results reveal that galangin protects human keratinocytes by activating ERK/AKT-Nrf2, leading to elevated expression of GSH-synthesizing enzymes.