紫背天葵黄酮的体内外抗氧化作用

Antioxidant Activity of the Flavonoids of Gynura in Vitro and in Vivo

采用体积分数80%的乙醇提取紫背天葵中的总黄酮并测定其含量,将粗提液萃取,经AB-8型大孔吸附树脂纯化,以Vc为对照,测定紫背天葵总黄酮粗提液、纯化液对二苯代苦味酰基自由基(DPPH.)、羟基自由基(.OH)和超氧阴离子自由基(O2-.)的清除能力,并考察紫背天葵黄酮纯化物的体内抗氧化效果。结果表明,紫背天葵中粗黄酮含量为13.928 mg/g,纯化比率为32.79%;紫背天葵总黄酮粗提液、纯化液对3种自由基均有不同程度的清除作用,且清除作用随黄酮质量浓度的升高而增强,纯化液的清除作用强于粗提液;低剂量紫背天葵黄酮纯化物实验组小鼠肝脏和脑组织中超氧化物歧化酶(SOD)活力和肝脏过氧化氢酶(CAT)活力显著高于对照组(p<0.05),而脑中的丙二醛(MDA)含量显著低于正常对照组(p<0.05)。

The total flavonoids in Gynura were extracted in volume fraction 80% alcohol and purified,and their antioxidant activity in vitro and in vivo was studied.After removing impurities,the crude extracts were purified with type AB-8 macroporous adsorption resin.The content of the total flavonoids was determined by spectrophotometry.The antioxidant activity of the total flavonoids in vitro was analyzed by using different assays with Vc as cross reference,for example,DPPH radical（DPPH·） scavenging assay,hydroxyl radical（·OH） scavenging assay,superoxide radical（O2-·） scavenging assay.The antioxidant activity of the purified flavonoids in vivo was also investigated.The content of total crude flavonoids from Gynura was 13.928 mg/g,and the purification ratio was 32.79%.The radical scavenging effect was enhanced with increasing flavonoid concentration.The scavenging effect of the purified flavonoids was greater than the crude extracts.The level of superoxide dismutase（SOD） activity in the brain and liver of mice was significantly higher in low doses groups than in normal control groups（p〈0.05）,so was the level of catalase（CAT） activity in liver.The brain malondialdehyde（MDA） content was obviously lower than that of the normal control groups（p〈0.05）.