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Positions of Hydroxyl Groups in Chrysin are Critical for Inhibiting Plasminogen Activator Inhibitor-1 Release from Human Umbilical Vein Endothelial Cells

4区 · 医学

ArticleOA

作者: Kanai, Shiho ; Atsumi, Gen-ichi ; Ishibashi, Kenichi ; Ando, Kumiko ; Tatefuji, Tomoki ; Takata, Yuko ; Taniguchi, Masahiko ; Ohkura, Naoki

Chrysin suppresses the TNFa-induced increase in the secretion of plasma plasminogen activator inhibitor 1 (PAI-1), a risk factor for thrombotic diseases, from human umbilical vein endothelial cells (HUVECs). The present study aimed to determine the association between the location of the hydroxyl groups in chrysin to levels of PAI-1 in the medium of HUVEC stimulated with TNFα, We cultured HUVEC for 3 h in medium containing chrysin or various flavonoids and then stimulated them with TNFα (10 ng/mL) for 12 h. Levels of PAI-1 antigen measured using ELISA showed that chrysin significantly inhibited the PAI-1 increase with an IC50 of 15.6 μM. The flavones, galangin, baicalein, 5-hydroxyflavone, 6-hydroxyflavone, 7-hydroxyflavone and quercetin did not significantly inhibit the PAI-1 increase. Apigenin and luteolin were cytotoxic and thus their ability to inhibit PAI-1 production could not be evaluated. Chrysin also inhibited PAI-1 mRNA expression whereas the other compounds did not. Hydroxyl groups located in the A-5 and A-7 positions were essential for the inhibitory activity, which along with cytotoxicity, was significantly influenced by adding a third hydroxyl group.

2016-01-01·Journal of Intercultural Ethnopharmacology

Effects of a diet containing Brazilian propolis on lipopolysaccharide-induced increases in plasma plasminogen activator inhibitor 1 (PAI-1) levels in mice

Article

作者: Tatefuji, Tomoki ; Oishi, Katsutaka ; Ohkura, Naoki ; Kihara-Negishi, Fumiko ; Atsumi, Gen-Ichi

BACKGROUNDBrazilian propolis has many biological activities including the ability to help prevent thrombotic diseases, but this particular effect has not been proven. Plasma levels of plasminogen activator inhibitor-1 (PAI-1), an inhibitor of fibrinolysis, increase under inflammatory conditions such as infection, obesity and atherosclerosis and such elevated levels predispose individuals to a risk of developing thrombotic diseases.AIMThis study aimed to determine the effects of a diet containing Brazilian propolis on lipopolysaccharide (LPS)-induced increases in plasma PAI-1 levels.MATERIALS AND METHODSMice were fed with a diet containing 0.5% (w/w) Brazilian propolis for 8 weeks. Thereafter, the mice were subcutaneously injected with saline containing 0.015 mg/kg of LPS and sacrificed 4 h later.RESULTSOrally administered Brazilian propolis significantly suppressed the LPS-induced increase in PAI-1 antigen and its activity in mouse plasma.CONCLUSIONThis study indicated that Brazilian propolis contains natural products that can decrease thrombotic tendencies in mice.

2012-01-01·Biological and Pharmaceutical Bulletin4区 · 医学

Inhibitory Effect of Gnetin C, a Resveratrol Dimer from Melinjo (<i>Gnetum gnemon</i>), on Tyrosinase Activity and Melanin Biosynthesis

4区 · 医学

Article

作者: Kanno, Tomoko ; Hashimoto, Ken ; Tatefuji, Tomoki ; Yoshimatsu, Maiko ; Yanagihara, Miyako ; Inoue, Akinori

Tyrosinase is the key enzyme involved in melanogenesis. The aim of this study was to investigate the in vitro inhibitory effects of gnetin C, a resveratrol dimer isolated from melinjo (Gnetum gnemon) seeds, on tyrosinase activity and melanin biosynthesis in murine B16 cells. The inhibitory activities of gnetin C and resveratrol were shown to be almost equal against tyrosinase and melanin biosynthesis in the cells. The IC(50) values of gnetin C activity against tyrosinase and melanin biosynthesis were 7.0 and 7.6 µM, respectively, whereas resveratrol demonstrated IC(50) values of 7.2 and 7.3 µM, respectively. These results indicated that gnetin C inhibited melanogenesis, in a manner similar to that of resveratrol, by inhibiting tyrosinase and may therefore function as a new skin-whitening agent. However, the direct effects of gnetin C and resveratrol on murine tyrosinase activities were not equal. The IC(50) value of resveratrol was 10.1 µM, while gnetin C only exhibited a 25.2% enzyme inhibition at 16 µM. The IC(25) values for gnetin C and resveratrol were 15.5 and 4.0 µM, respectively. Therefore, it is suggested that the effects of gnetin C may be due to mechanisms other than the direct inhibition of tyrosinase activity.

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