3种薏米的多酚提取物清除过氧化氢自由基抗氧化能力评价

Polyphenol Content and Hydrogen Peroxide Radical-Scavenging Capacity of Extracts from Three Cultivars of Adlay

选取黑谷、辽宁5号和龙薏1号3个品种薏米样品,经提取获得游离型和结合型多酚类化合物,采用改进的Folin-Ciocalteu比色法,用酶标仪测定其多酚含量;采用过氧化氢自由基清除能力(PSC)测定方法,于荧光酶标仪中测定提取物中的总抗氧化活性。结果表明:龙薏1号薏米游离型多酚和结合型多酚含量显著性高于贵州黑谷薏米和辽宁5号薏米,其结合型多酚含量占总多酚含量的45.28%;总抗氧化能力最高的是龙薏1号薏米,3种薏米中结合型抗氧化能力占总抗氧化能力的43.64%;其总多酚含量与总抗氧化能力之间有显著的相关性(R2=0.935),总多酚抗氧化能力和游离多酚型抗氧化能力具有显著相关性(P<0.05),游离型总多酚含量和总抗氧化能力中游离型含量显著高于结合型含量(P<0.05)。

Free phenolic extracts and bound phenolic extracts from three different cultivars of adlay, Heigu, Lianning No.5 and Longyi No.1 were prepared and analyzed for total phenolic content by a modified Folin-Ciocalteu colorimetric method using a microplate reader. At the same time, antioxidant activity evaluation of these extracts was carried out using peroxyl hydroxyl scavenging capacity （PSC） assay. Longyi No.1 was significantly richer in both free and bound phenolics than Heigu and Lianning No.5. The ratio of bound to total phenolics in Longyi No.1 was 45.28%. Moreover, free, bound and total phenolics from Longyi No. 1 showed a higher hydrogen peroxide radical scavenging capacity than those from other two cultivars. For these adlay cultivars, the average contribution rate of bound phenolics to total hydrogen peroxide radical scavenging capacity was 43.64%. They revealed a significant correlation between total phenolic content and hydrogen peroxide radical scavenging capacity （R^2 = 0.935）. A significant correlation was also observed between the hydrogen peroxide radical scavenging capacity of bound phenolics from adlay and its total hydrogen peroxide radical scavenging capacity （P〈0.05）. Furthermore, free phenolics had significantly higher relative content and larger contribution to total hydrogen peroxide radical scavenging capacity than bound phenolics （P〈0.05）.