玉米须提取物清除自由基和抑制脂质过氧化作用

背景与目的:探讨玉米须提取物的自由基清除能力和抑制不同氧化剂激发的脂质过氧化作用及其剂量反应关系.材料与方法:回流法制备玉米须醇提物(maydis stigma extract,MSE).采用·OH和O2两种化学发光体系,加入不同浓度玉米须醇提物后测定发光强度来检测其自由基清除能力.采用差速离心法提取10只雄性SD大鼠肝微粒体,并以Vit C/Fez 、过氧基异丙苯(curnine hydroperoxide,CHP)和CCl4/辅酶Ⅱ(nieotinamide-adenine dinueleotide phosphate,NADP )为激发剂建立微粒体脂质过氧化(lipid peroxidation,LPO)模型,加人不同浓度的玉米须提取物及阳性药物对照,通过比色法测定其对脂质过氧化产物丙二醛(malondialdehyde,MDA)的抑制作用.结果:玉米须提取物能显著清除化学发光体系产生的·OH和O2,且随着浓度的升高,发光强度呈下降趋务,均呈明显量效关系(r=0.922,P＜0.05;r=0.863,P＜0.05).在微粒体脂质过氧化模型中,玉米须提取物各浓度组MDA含量低于阴性对照组,并且在一定终浓度内(6.25～2000 μg/ml)有剂量-效应关系(r分别为0.935,0.931,0.79;P均＜0.05).结论:玉米须提取物在3.55～2000 μg/ml浓度范围内具有较强的自由基清除能力和抑制不同氧化剂激发的脂质过氧化作用.该结果为玉米须在与自由基相关疾病中的保护作用提供了实验依据.

Free Radical Scavenging and Antilipoperoxidant Properties of Maydis Stigma Extract

BACKGROUND AND AIM:To investigate the free radical scavenging and antilipoperoxidant activities of Maydis stigma extract and their dose-response relationship.MATERIALS AND METHODS:Sprague-Dawley rats were killed and the livers were removed to isolate the microsome by differential centrifugation.The ethanol extract of Maydis stigma were obtained by recirculating.We investigated the effects of the ethanol extract of Maydis stigma(MSE)on luminol-enhanced chemiluminescence of superoxide/hydroxyl radical scavenging properties in cell free system.We also measured malondialdehyde(MDA)from the microsomal suspension and studied the relationship between the lipid peroxidation and the antioxidant metabolism of MSE in rat liver microsomes.RESULTS:MSE possessed very high radical scavenging activity in both chemiluminescence assays.Furthermore,the extract exhibited a significant concentration-dependent inhibition of lipid peroxidation in rat liver microsomes induced by Fe2 /ascorbate,cumene hydroperoxide(CHP),and NADP /CCl4.CONCLUSION:The data clearly demonstrated the free radical scavenging and antilipoperoxidant properties of MSE supporting its reported biological activities.