淫羊藿苷与淫羊藿次苷Ⅱ的体外抗氧化作用

Antioxidant effects of icariin and icariside Ⅱ in vitro

目的:检测淫羊藿苷和淫羊藿次苷Ⅱ的体外抗氧化活性,阐明淫羊藿黄酮类化合物的抗氧化机制。方法:以抗坏血酸(Vc)、二丁基羟基甲苯(BHT)为阳性对照,测定淫羊藿苷、淫羊藿次苷Ⅱ和BHT对1,1-二苯基-2-苦苯肼自由基(DPPH.)的清除率;铁氰化钾还原法测定其还原力;利用NADH-NBT-PMS系统测定其对超氧阴离子(O2-.)的清除率;2-脱氧-D-核糖降解法测定淫羊藿苷和淫羊藿次苷Ⅱ对羟自由基(OH.)的清除率,硫代巴比妥酸法测定其对脂质过氧化的抑制率,β-胡萝卜素-亚油酸自氧化体系测定其总抗氧化能力。结果:不同样品对DPPH.均有一定的清除作用,淫羊藿次苷Ⅱ清除DPPH.的能力较淫羊藿苷强(P<0.05)。淫羊藿苷和淫羊藿次苷Ⅱ在浓度梯度范围内对O2-.有一定的清除作用,均表现出一定的浓度依赖性,与同浓度的BHT比较,淫羊藿苷和淫羊藿次苷Ⅱ对O2-.的清除率较低,且淫羊藿苷的清除能力略低于淫羊藿次苷Ⅱ。淫羊藿苷和淫羊藿次苷Ⅱ在浓度为0.1～0.5g.L-1时对OH.清除率分别为(16.76±0.35)%～(40.56±1.46)%和(15.65±0.72)%～(28.51±0.91)%。当浓度为0.9g.L-1时,淫羊藿苷、Vc和淫羊藿次苷Ⅱ对脂质过氧化的抑制率为(58.79±1.56)%、(75.05±2.12)%和(37.82±1.43)%。随着浓度的增加,抑制率不再有显著的增加。随着样品浓度的增加,淫羊藿苷、淫羊藿次苷Ⅱ和标准品Vc还原力均表现出浓度依赖性。30～120min内淫羊藿次苷Ⅱ的抗氧化活性均低于淫羊藿苷和BHT(P<0.05或P<0.01)。淫羊藿苷和淫羊藿次苷Ⅱ在体外抗氧化的各项指标中表现出的抗氧化活性均弱于Vc和BHT。结论:淫羊藿苷和淫羊藿次苷Ⅱ在清除DPPH.、O2-.、OH.和抑制脂质过氧化、总抗氧化能力和还原力方面,均具有明显的抗氧化能力。

Objective To investigate the antioxidant activities of icariin and icariside Ⅱ,and to clarify the possible antioxidant mechanism.Methods Using Vc and butylated hydroxytoluene（BHT）as positive controls,the clearance rates of icariin,icariside Ⅱ and BHT on 1,1-diphenyl-2-picryl-hydrazyl radical（DPPH·）,superoxide anion（O2-·） and hydroxyl free radical（OH·） were measured;the reduction rates of samples were detected by the system of potassium ferricyanide;the capacities of samples were detected by NADH-NBT-PMS system;the inhibitory rates of lipid peroxidation were detected by thiobarbituric acid（TBA） method;the total antioxidant activities were determined by bleaching of β-carotene suboleic acid system.Results The samples showed concentration-dependent scavenging capacities of DPPH·.The clearance abilities of icariside Ⅱ were higher than those of icariin（P〈0.05）.The clearance effects of icariin and icariside Ⅱ were concentraion-dependent;compared with the same concentration of BHT,the O2-· clearance rates of icariside Ⅱ and icariin were slightly lower,and the clearance rate of icariin was much lower than that of icariside Ⅱ.The OH· clearance rates of icariin and icariside Ⅱ in the concentration of 0.1-0.5 g·L-1 were（16.76±0.35）%-（40.56±1.46）% and（15.65±0.72）%-（28.51±0.91）%.When the concentration was 0.9 g·L-1,the inhibitory rates of lipid peroxidation of icariin,Vc and icariside Ⅱ were（58.79±1.56）%,（75.05±2.12）% and（37.82±1.43）%.The inhibitory rates no longer changed with the dose increasing.As the sample concentration increasing,the reduction capacities of icariin,Vc and icariside Ⅱ showed concentration-dependent tendence.In 30-120 min the total antioxidant activity of icariside Ⅱ was lower than those of icariin and BHT（P〈0.05 or P〈0.01）.The antioxidant activities of icariin and icariside Ⅱ in vitro were weaker than those of Vc and BHT.Conclusion Icariin and icariside Ⅱ shows obvious antioxidant activities in scavenging of DPPH·,O2-· and OH· and inhibition of lipid peroxidation,the total antioxidant activity and the reduction activity.