文献类型：期刊文献

英文题名：Antioxidant activity of a flavonoid-rich extract of Hypericum perforatum L. in vitro

作者：Zou, YP; Lu, YH; Wei, DZ

机构：[1]E China Univ Sci & Technol, Inst Biochem, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China

年份：2004

卷号：52

期号：16

起止页码：5032

外文期刊名：JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000223137000017)】；

语种：英文

外文关键词：Hypericum perforatum L.; antioxidant activity; flavonoid; free radicals; reducing power; lipid peroxidation; liposome; deoxyribose degradation

摘要：A flavonoid-rich extract of Hypericum perforatum L. (FEHP) was prepared by adsorption on macroporous resin and desorption by ethanol. Total flavonoid content of FEHP was determined by a colorimetric method. The major constituents of FEHP, including rutin, hyperoside, isoquercitrin, avicularin, quercitrin, and quercetin, were determined by HPLC analysis and confirmed by LC-MS. Different antioxidant assays were utilized to evaluate free radical scavenging activity and antioxidant activity of FEHP. FEHP was an effective scavenger in quenching DPPH and superoxide radical with IC50 of 10.63 mug/mL and 54.3 mug/mL, respectively. A linear correlation between concentration of FEHP and reducing power was observed with a coefficient of r(2) = 0.9991. Addition of 150 mug of FEHP obviously decreased the peroxidation of linoleic acid during 84 h incubation, but the amount of FEHP over 150,mug did not show statistically significant inhibitory effect of peroxidation of linoliec acid (p > 0.05). FEHP exhibited inhibitory effect of peroxidation of liposome induced both by hydroxyl radical generated with iron-ascorbic acid system and peroxyl radical and showed prominent inhibitory effect of deoxyribose degradation in a concentration-dependent manner in site-specific assay but poor effect in non-site-specific assay, which suggested that chelation of metal ion was the main antioxidant action. According to the results obtained in the present study, the antioxidant mechanism of FEHP might be attributed to its free radical scavenging activity, metal-chelation activity, and reactive oxygen quenching activity.