• Mass Spectrometry Letters
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• v.11 no.4
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• pp.113-117
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• 2020

Cytochrome P450 2J2 (CYP2J2) is a member of the cytochrome P450 superfamily, and is known to be arachidonic acid epoxygenase that mediates the formation of four bioactive regioisomers of epoxyeicosatrienoic acids (EETs). CYP2J2 is also involved in the metabolism of drugs such as albendazole, astemizole, danazol, ebastine, and terfenadine. CYP2J2 is highly expressed in the heart and cancer tissues. In this study, the inhibitory potential of ten natural products against CYP2J2 activity was evaluated using human liver microsomes and tandem mass spectrometry. Among them, bilobetin, which is a kind of biflavonoid, exhibits a strong inhibitory effect against the CYP2J2-mediated astemizole O-demethylation (IC50 = 0.73 μM) and terfenadine hydroxylation (IC50 = 0.89 μM). This result suggests that bilobetin can be used as strong CYP2J2 inhibitor in drug metabolism study.

• Natural Product Sciences
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• v.6 no.1
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• pp.1-4
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• 2000

Four biflavonoids were isolated from the leaves of Cephalotaxus koreana. Based on spectroscopic data, the compounds were identified as amentoflavone-7',7",4',4"'-tetramethyl ether, sciadopitysin, ginkgetin and bilobetin, respectively.

• Korean Journal of Pharmacognosy
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• v.21 no.2
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• pp.111-120
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• 1990

Five biflavones and sevenflavonolglycosideswereisolatedfromtheleaves of Ginkgo biloba. They were sciadopitysin(1), ginkgetin(2), isoginkgetin(3), bilobetin(4), amentoflavone(5), kaempferol 3-O-[$6'-O-{\rho}-coumaroyl-{\beta}-_D-glucopyranosyl(1{\rightarrow}2)-{\alpha}-_Lrhamnopyranoside$](6), quercetin 3-O-[$6'-O-{\rho}-coumaroyl-{\beta}-_D-glucopyranosyl(1{\rightarrow}2)-{\alpha}-_Lrhamnopyranoside$](8), rutinosides of kaempferol(7), isorhamnetin(9), quercetin(10), laricitrin(11), and kaempferol 3-O-($2',6'-{\alpha}-_L-dirhamnopyranosyl-{\beta}-_{D}-glucopyranoside$)(12). The structures were established by spectroscopic and chemical methods.

• Journal of Life Science
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• v.15 no.2 s.69
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• pp.231-235
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• 2005

Matrix metalloproteinases (MMPs) are a family of structurally and functionally related zinc-dependent enzymes responsible for proteolytic degradation of extracellular matrix components such as base membrane or interstitial stroma. MMPs play an important role in a variety of physiological and pathological tissue remodeling processes, including wound healing, embryo implantation, tumor invasion and metastasis. Since MMP-9 (gelatinase B) has unique ability to cleave type IV collagen, gene expression of MMP-9 has been focused on as a pharmacological target. Flavonoids are a class of compounds that are widely spread in plants. In the coures of screening for the suppressors of MMP-9 gene expression from natural products, Metasequoia glyptostroboides was selected. Six flavonoids, sciadopitysin, isoginkgetin, bilobetin, 2,3-dihydrohinokiflavone, luteolin and apigenin were purified as suppressors of MMP-9 gene expression from M. glyptostroboides. The suppressing activity of the isolated flavinoids on the MMP-9 gene expression was measured by gelatin zymography and Nothern blot analysis.

• Korean Journal of Pharmacognosy
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• v.24 no.1
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• pp.54-57
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• 1993

The seasonal variations of five biflavones from Ginkgo biloba leaves from May to November were investigated by a reversed phase HPLC method. The total amount of biflavones was increased with time to reach its maximum in yellow autumnal leaves. Each biflavone showed a similar tendency. It increased rapidly about 3.1-fold from May to June and thereafter gradually increased about 2.5-fold. The ratio of each biflavone content to the total amount of biflavones was in the order of as follows: isoginkgetin>sciadopitysin>bilobetin>ginkgetin>amentoflavone.

• Archives of Pharmacal Research
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• v.29 no.12
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• pp.1074-1079
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• 2006

As part of our research on phytochemicals that exert protective effects against diseases related to reactive nitrogen species, we have evaluated the scavenging activity of the yellow leaves of Ginkgo biloba on $ONOO^{-}$. The methanol extract and ethyl acetate fraction obtained from yellow leaves of G. biloba evidenced a marked scavenging activity on authentic $ONOO^{-}$. Repeated column chromatography of the active ethyl acetate soluble fraction on silica gel, Sephadex LH-20, and RP-18, resulted in the purification of 15 known compounds, including sciadopitysin (1), ginkgolide B (2), bilobalide (3), isoginkgetin (4), kaempferol (5), luteolin (6), protocatechuic acid (7), bilobetin (8), amentoflavone (9), ${\beta}-sitosterol$ glucopyranoside (10), kaempferol 3-O-rhamnopyranoside (11), kaempferol 3-O-glucopyranoside (12), kaempferol $3-O-[{6^{'}-O-p-coumaroyl-{\beta}-D-glucopyranosyl(1{\rightarrow}2)-{\alpha}-L-rhamnopyranoside]$ (13), kaempferol 3-O-rutinoside (14), and 6-hydroxykynurenic acid (15). Among the compounds isolated, flavonoids (5, 6 and 11-14), protocatechuic acid (7), and 6-hydroxykynurenic acid (15) all exhibited marked scavenging activities on authentic $ONOO^{-}$. The $IC_{50}$ values of 5-7, 11-14 and 15 were as follows: $2.86{\pm}0.70,\;2.30{\pm}0.04,\;2.85{\pm}0.10,\;5.60{\pm}0.47,\;4.16{\pm}1.65,\;2.47{\pm}0.15,\;3.02{\pm}0.48,\;and\;6.24{\pm}0.27\;{\mu}M$, respectively. DL-Penicillamine ($IC_{50}=4.98{\pm}0.27\;{\mu}M$) was utilized as a positive control. However, the other compounds (1-4, 8-10) exerted no effects against $ONOO^{-}$.