Inhibitory effects of flavonoids on LPS-induced NO production in RAW 264.7 cells and their structure-activity relationships

• Main Authors: Jung-Pei Chang, 張榮珮
• Other Authors: Wun-Chang Ko
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/28964186022973283718

碩士 === 臺北醫學大學 === 藥理學研究所 === 92 === The inhibitory effects of flavonoids on NO production in RAW 264.7 cells were still debated. Therefore, it needs further investigation. To attenuate the effect of surface tension of culture medium, we incubated RAW 264.7 cells in 12-well, but not 96-well plates. Thirteen flavonoids, divided into four classes, flavones, flavonols, flavanones and isoflavones, were used to examine their inhibitory effects on LPS-induced NO production. The results revealed that apigenin, luteolin, diosmetin, eriodictyol, quercetin, genistein and prunetin had more potent effects (IC50＜10 μM). Some of them were selected for examining their suppressive effects on iNOS protein expression. The results demonstrated that luteolin, eriodictyol and prunetin attenuated LPS-induced iNOS protein expression in a dose-dependent manner using Western blot analysis. The attenuation was not due to cell cytotoxicity of these flavonoids. The IC50 values differ from those of NO production, respectively (Table 2). In addition, in a in vitro system, flavonoids did not attenuate SNP-induced NO production, with an exception that flavones (apigenin and diosmetin), and isoflavones (genistein and prunetin) concentration-dependently attenuated the NO production. This attenuating effects were not greater than 30%. However, all tested flavonoids significantly had NO-scavenging effects, but the effects were not greater than 25%. The above results revealed flavonoids attenuate NO production maybe due to the inhibition of iNOS protein expression.