海南白沙绿茶的抗氧化活性及其酚酸类组成的HPLC-MS分析

采用DPPH体系、ABTS体系和Oyaizu法对白沙绿茶的甲醇提取物、70%乙醇提取物和水提取物的抗氧化活性进行测定,并利用HPLC-MS对活性较高的乙醇提取物的抗氧化特征性成分进行分析。结果表明:白沙绿茶3种提取物均具有一定的抗氧化能力,呈浓度效应关系。其中3种提取物中以70%乙醇提取物对DPPH和ABTS清除能力最强,而还原力则弱于水提取物和甲醇提取物。通过HPLC-MS从70%乙醇提取物中得到24个酚类物质,其中15个酚类物质被鉴定为新绿原酸、花旗松素-3-O-芸香糖苷、绿原酸、隐绿原酸、去甲氧基姜黄素、表儿茶素、山奈酚-3-O-芸香糖苷、花旗松素-3-O-葡萄糖苷、槲皮素-双己糖苷、Di-O-咖啡酰奎宁酸、槲皮素、山奈素-3-O-戊糖苷、牛蒡子苷、杨梅素和山奈素。

Antioxidant Activity Assay and HPLC-MS Analysis of Polyphenols Constituents of Baisha Green Tea

The antioxidant activity of methanol, 70% ethanol and water extract of Baisha Green Tea was determined by using three complementary methods in vitro: the DPPH radical-scavenging activity, the ABTS radical-scavenging activity, and reducing ability. In addition, the characteristic antioxidant constituents of 70% ethanol extract were analyzed by HPLC-MS. In vitro antioxidant assays showed that the three extracts possessed varying degrees of efficacy in each assay in a dose-dependent manner. 70% ethanol extract exhibited the strongest DPPH radical-scavenging ability and ABTS radical-scavenging ability in the three extracts, while it showed lower reducing ability than water extract and methanol extract. Twenty-four main constituents in the 70% ethanol extract were obtained by HPLC-MS, and the 15 major polyphenols were identified asneochlorogenic acid, taxifolin-3-O-rutinoside, chlorogenic acid, cryptochlorogenic acid, demethoxycurcumin, epicatechin, kampferol-3-O-rutinoside, Taxifolin-3-O-gluconide, quercetin-dihexosides, Di-O-caffeoylquinic acid, kaempferide-3-O-pentoside, arctiin, quercetin, myricetin, and kaempferid.