星萼金丝桃的化学成分和抗氧化活性研究

Chemical constituents of Hypericum stellatum and their antioxidant bioactivities

星萼金丝桃Hypericum stellatum是中国西南地区特有种,也是当地一种重要的民族药用植物。采用UPLC-Q-TOF-MS分析星萼金丝桃的化学成分,初步鉴定了17个化合物,通过DPPH自由基清除法测定抗氧化活性,Folin-Ciocalteu法测定总酚含量,星萼金丝桃乙酸乙酯萃取层显示出较强的抗氧化活性和较高的总酚含量。选定抗氧化活性强和总酚含量较高的乙酸乙酯层进行化学成分研究,利用正相硅胶、Sephedex LH-20、循环制备高效液相等多种色谱手段对地上部位提取物进行分离纯化,通过一维,二维核磁共振波谱数据对所得化合物进行结构鉴定,在该层萃取物中分离得到10个化合物,分别鉴定为槲皮素(Ⅰ),槲皮素-3-O-β-D-葡萄糖苷(Ⅱ),1,3,6,7-四羟基口山酮(Ⅲ),1,3,5,6-四羟基口山酮(Ⅳ),1,3,7-三羟基口山酮(Ⅴ),3,6,7-三羟基-1-甲氧基口山酮(Ⅵ),calycinoxanthon D(Ⅶ),咖啡酸酸乙酯(Ⅷ),绿原酸(Ⅸ),绿原酸乙酯(Ⅹ)。该研究首次报道我国特有植物星萼金丝桃的化学成分和生物活性,初步明确星萼金丝桃清除自由基、抗氧化活性的物质基础。

Hypericum stellatum is an important ethnomedicinal plant endemic to southwest China. Ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry( UPLC-Q-TOF-MS) was applied to analyze the chemical constituents of H. stellatum. Seventeen compounds from H. stellatum were tentatively identified using UPLC-Q-TOF-MS data. Antioxidant activity and total phenolic content were investigated by DPPH assay and Folin-Ciocalted methods. The Et OAc extract with high total phenolic content showed prominent antioxidant activity. The Et OAc extract of H. stellatum was separated and purified by column chromatography,including silica gel,Sephedex LH-20,and RP-HPLC. The isolates were defined by 1 D,2 D NMR data. As a result,ten compounds were isolated and assigned as quercetin( Ⅰ),quercetin 3-O-β-D-glucopyranoside( Ⅱ),1,3,6,7-tetrahydroxylxanthone( Ⅲ),1,3,5,6-tetrahydroxyxanthone( Ⅳ),1,3,7-trihydroxyxanthone( Ⅴ),3,6,7-trihydroxy-1-methoxyxanthone( Ⅵ),calycinoxanthon D( Ⅶ),caffeic acid ethyl ester( Ⅷ),chlorogenic acid( Ⅸ) and chlorogenic acid ethyl ester( Ⅹ). This is the first report on chemical constituents and bioactivity of H. stellatum. The antioxidant activity of chemical constituents was tentatively found,which provided a foundation for further researches on the genus Hypericum and the traditional uses of H. stellatum.