DPPH法研究麦冬提取物抗氧化活性

Study on Antioxidant Activity of Ophiopogon japonicus Extracts by DPPH Assay

摘要:

将干燥麦冬块根进行提取，分别得到麦冬总皂苷、总黄酮和总蛋白质三种提取物，并以DPPH法对三种提取物的抗氧化活性进行评价。选择抗氧化剂抗坏血酸、硫脲、儿茶素作为阳性对照，以IC50值作为评价样品清除DPPH自由基能力的指标。结果显示，在波长517 nm，DPPH的浓度在25.8~51.5 μg/mL线性关系良好。阳性对照抗坏血酸、硫脲、儿茶素的IC50值分别为87.0、482.9和10.2 μg/mL；麦冬总皂苷、总黄酮、总蛋白质的IC50值分别为509.0、79.4和46.0 μg/mL。根据IC50值评价各种物质的抗氧化性强弱顺序为：儿茶素﹥麦冬总蛋白质﹥麦冬总黄酮﹥抗坏血酸﹥硫脲﹥麦冬总皂苷。通过多元聚类分析表明麦冬总黄酮、总蛋白质与抗坏血酸、儿茶素具有类似的抗氧化活性强度，说明麦冬总黄酮和总蛋白质具有较强的抗氧化能力。

Abstract:

The total saponins, total flavonoids and total proteins were extracted from Ophiopogon japonicus. The antioxidant activity of three extracts were investigated by DPPH assay. Ascorbic acid, thiourea and catechins were used as posititive control and IC50 value as the evaluating criterion of DPPH free radical scavenging capability. The results show that at the wavelength of 517 nm, the calibration curves showed good linearity in the range of 25.8~51.5 μg/mL of DPPH. The IC50 of antioxidants(ascorbic acid, thiourea and catechins) were 87.0，482.9 and 10.2 μg/mL respectively. The IC50 of the extracts from O. japonicus(total saponins, total flavonoids and total proteins) were 509.0，79.4 and 46.0 μg/mL. The strength in the order of IC50 was catechins﹥total proteins﹥total flavonoids﹥ascorbic acid﹥thiourea﹥total saponins. In addition, multi-cluster analysis show that total flavonoids, total proteins, ascorbic acid and catechins had a similar intensity of antioxidant activity, which sihgnifies that the total flavonoids and total proteins from O. japonicus had strong antioxidant activity.