异丹叶大黄素的体外抗氧化作用

 目的 异丹叶大黄素(isorhapontigenin, ISOR)是从中药射干中提取的化学成分，是与白藜芦醇化学结构相似的芪衍生物。通过多种模型研究ISOR的体外抗氧化作用。方法 采用Fe²⁺-半胱氨酸（Cys）、VitC-ADP-Fe²⁺和H₂O₂等自由基发生系统诱发大鼠肝微粒体、脑线粒体及突触体的氧化损伤，观察ISOR对此过程中MDA生成、GSH降低及超微弱化学发光增强的影响，并观察ISOR对用CuSO₄-Phen-VitC-H₂O₂系统损伤DNA后8-OH-dG的特征性超微弱化学发光增强影响。结果 ISOR能显著抑制Fe²⁺-Cys诱导的大鼠肝微粒体、脑线粒体及突触体膜氧化损伤过程中MDA的生成，并能显著抑制H₂O₂ 诱导的脑线粒体及突触体GSH的降低；显著抑制VitC-ADP-Fe²⁺系统引起的微粒体膜氧化损伤时超微弱化学发光增强，并能显著降低DNA受氧化损伤后微弱化学发光的强度。经典抗氧化剂VitE 10^-4mol·L^-1抑制MDA生成及GSH降低的作用仅相当于ISOR10^-5或10^-6 mol·L^-1的效果。结论 ISOR具有较强的抗氧化作用，且其活性明显强于经典抗氧化剂VitE。

Antioxidative activity of isorhapontigenin in vitro

OBJECTIVE To investigate the antioxidative activity of natural isorhapontigenin (ISOR) with similar chemical structure to resveratrol.METHODS The oxidative damage of rat liver microsomes, brain mitochondria and synaptosomes was induced by Fe²⁺-Cys, VitC-ADP-Fe²⁺ and H₂O₂,respectively.The formation of malondialdehyde (MDA), decrease of reduced glutathione (GSH) and increase of ultra-weak chemiluminescence during the lipid peroxidation process were determined．The characteristic ultra-weak chemiluminescence of oxidative DNA damage induced by CuSO₄-Phen-VitC-H₂O₂ system was also observed.RESULTS ISOR significantly inhibited MDA formation in liver microsomes, brain mitochondria and synaptosomes induced by Fe²⁺-Cys. Also,ISOR markedly prevented the decrease of GSH in mitochondria and synaptosomes induced by H₂O₂.The increase of ultra-weak chemiluminescence during lipid peroxidation induced by VitC-ADP-Fe²⁺ as well as oxidative DNA damage induced by CuSO₄-Phen-VitC-H₂O₂ were all inhibited by ISOR.The effects of ISOR 10^-5 and 10^-6 mol·L^-1 on the MDA formation and decrease of GSH were corresponding to that of classical antioxidant vitamin E (10^-4 mol·L^-1).CONCLUSION ISOR possesses potent antioxidative activity and is much more potent than vitamin E.