8-羟基染料木素及其甲基化衍生物的合成与抗缺氧活性研究

Synthesis and anti-hypoxic activity of 8-hydroxygenistein and its methylated derivatives

目的 制备8-羟基染料木素及其甲基化衍生物,并考察其抗氧化和抗缺氧活性,初步阐明其构效关系。方法以鹰嘴豆芽素A为原料,经甲基化、溴代、甲氧基化和去甲基化等反应,得到8-羟基染料木素(化合物Ⅰ)及3个甲基化衍生物(化合物Ⅱ~Ⅳ);用DPPH自由基清除实验测定4个目标化合物的自由基清除活性;CCK-8法考察其对缺氧PC12细胞的保护作用,于光镜下观察经目标化合物处理后的细胞形态,比色法测定细胞上清液中乳酸脱氢酶(LDH)的活性。结果 目标化合物Ⅰ~Ⅳ的结构通过对比文献或经NMR、MS等波谱手段确认,HPLC检测纯度均>98%。化合物Ⅰ、Ⅱ对DPPH自由基有较好的清除作用。除化合物Ⅳ外,化合物Ⅰ~Ⅲ均可显著提高缺氧PC12细胞的存活率,降低LDH的活性,维持细胞形态,减轻缺氧对PC12细胞的损伤,其活性顺序为:Ⅰ>Ⅱ>Ⅲ>Ⅳ。结论 8-羟基染料木素及其甲基化衍生物的DPPH自由基清除活性及对缺氧PC12细胞的保护作用随着分子结构中酚羟基数目的增加而增强,提示这些化合物的自由基清除作用可能是其发挥抗缺氧活性的主要机制,其中,8-羟基染料木素的活性最佳。

OBJECTIVE To investigate the antioxidant,anti-hypoxic activities and structure-activity relationship of 8-hydroxygenistein and its methylated derivatives.METHODS 8-hydroxygenistein(Ⅰ)and its three methylated derivatives(Ⅱ-Ⅳ)were obtained by methylation,bromination,methoxylation and demethylation reactions using biochanin A as raw material.The free radical scavenging activities of four target compounds were determined by DPPH radical scavenging assay.The protective effect against injury induced by hypoxia in PC12 cells was determined using CCK-8 assay.The cell morphology was observed using light microscope and the activities of LDH in cell supernatant was determined by colorimetry.RESULTS The structures of target compoundsⅠ-Ⅳwere confirmed by comparison with literature or NMR and MS spectral data.The purity of these compounds was measured by HPLC and determined to be higher than 98%.CompoundsⅠandⅡexhibited excellent scavenging activities on DPPH radical.Except compoundⅣ,compoundsⅠ-Ⅲsignificantly increased the survival rate of PC12 cells following hypoxia exposure,reduced the activity of LDH,maintained the morphology of cells,and then alleviated the damage induced by hypoxia in PC12 cells with the order ofⅠ>Ⅱ>Ⅲ>Ⅳ.CONCLUSION The DPPH radical scavenging activity of 8-hydroxygenistein and its methylated derivatives and their protective effects on PC12 cells following hypoxia exposure are enhanced with the increase of the number of phenolic hydroxyl groups in the molecular structure,suggesting that the free radical scavenging activity of these compounds may be responsible for their antihypoxic activity.8-hydroxygenistein exhibits the best activity.