6种淫羊藿黄酮抗氧化和抗肿瘤活性的比较

目的：初步探讨淫羊藿黄酮的抗氧化活性与其化学结构的关系以及抗肿瘤作用与取代基的关系。方法：利用硅胶和凝胶柱色谱分离淫羊藿中单体黄酮成分,根据化合物光谱数据(ESI-MS,¹HNMR和¹³CNMR)鉴定其结构,利用MTT法和DPPH法测定6个单体黄酮的细胞毒性和抗氧化清除自由基的能力。结果：从地上部分的醋酸乙酯萃取物中分离得到6个化合物,分别为淫羊藿苷(Ⅰ), 木犀草素(Ⅱ),宝藿苷II(Ⅲ),金丝桃苷(Ⅳ),朝藿素B(Ⅴ)及宝藿苷I(Ⅵ)。活性研究结果表明,在3.125～200 μmol·L^-1剂量,化合物Ⅰ,Ⅲ和Ⅵ对DPPH自由基基本上没有清除作用,而化合物Ⅱ,Ⅳ和Ⅴ对DPPH则显示出了较好的自由基清除作用,并随浓度的增加清除作用增强,其作用强度明显好于维生素C；化合物Ⅰ,Ⅱ,Ⅴ和Ⅵ对人乳腺癌细胞株(MCF-7)和人肝癌细胞株(HepG2)的生长均表现出增殖抑制作用,而化合物Ⅲ和Ⅳ对2种细胞株的生长则基本没有影响。结论：B环是黄酮类物质抗氧化、清除自由基的主要活性部位；黄酮8-位异戊烯基取代不是其抗肿瘤活性的决定因素。

Comparison of antioxidative and antitumor activities of six flavonoids from Epimedium koreanum

OBJECTIVE: To study the antioxidative and antitumor activities of flavonoids isolated from Epimedium koreanum. METHOD: The compounds were separated by column chromatography with silica gel and Sephadex LH-20, and identified by spectral a- nalysis (ESI-MS, 1H-NMR and 13C-NMR) respectively. DPPH radical scavenging assay and MTT assay were used to observe the antioxidative and antitumor abilities. RESULT: Six compounds were isolated from the the ethyl acetate extract of the aerial part. Their structures were identified as icariin (I), luteolin (II), baohuoside II (III), hyperoside (IV), epimedokoreanin B (V) and baohuoside I (VI). The results indicated that at concentrations of 3. 125-200 micromol x L(-1), compound I, III and VI had no ability to scavenge the DPPH radical, but the scavenging ability of compounds II, IV and V were stronger than that of Vit C in dose-dependant manner. Compounds I, II, V and VI could inhibit the proliferation of MCF-7 and HepG2 in dose-dependant manner, but compounds III and IV had no effect on the proliferation. CONCLUSION: The antitumor activity of E. koreanum may be partially related to the antioxidantive activity of flavonoids.