铁皮石斛茎、叶、花功能性成分、抗氧化活性及其相关性

Analysis of functional composition、antioxidant activity and their correlation in stem,leaf and flower from Dendrobium officinale

目的:探索铁皮石斛茎、叶、花主要功能性成分的差异性、抗氧化能力大小及抗氧化活性的主要贡献成分。方法:以铁皮石斛茎、叶、花为试验材料,分别采用苯酚-硫酸法、NaNO_(2)-Al_(3)+NaOH法、福林酚法和酸性染料比色法对其多糖、总黄酮、总多酚和总生物碱含量进行测定比较,研究茎、叶、花的抗氧化能力,并通过相关性分析确定其主要抗氧化活性成分。结果:铁皮石斛茎、叶、花中均含有多糖、黄酮、多酚和生物碱类成分,但含量差异极显著(P<0.01),其中多糖含量为茎(31.00%)>叶(15.04%)>花(8.11%);总黄酮和总多酚含量均以花中最高,分别为2.133%和15.71%,叶中次之;总生物碱含量以花中最高,达0.0223%,为茎中的近4倍;铁皮石斛茎、叶、花均具有较高抗氧化活性,且随着浓度的增大,其对DPPH自由基和ABTS自由基的清除能力逐渐增强,其中花的水提物和醇提物清除DPPH自由基和ABTS自由基的IC 50均最小,说明其氧化活性最大,较接近于维生素C的。相关性分析发现,铁皮石斛茎、叶、花抗氧化活性与总黄酮、总多酚和总生物碱含量呈正相关,与多糖含量无明显相关性,说明总黄酮和总多酚含量对铁皮石斛茎、叶、花的抗氧化活性贡献最大,总生物碱含量的贡献显著。结论:铁皮石斛叶和花同样具有广阔的应用价值和开发前景。

Objective:To strengthen the comprehensive utilization of Dendrobium officinale(D.officinale)resources.Methods:The functional composition,antioxidant activity and their pearson correlation analysis of D.officinale stem,leaf and flower were studied and compared.Results:The results showed that the contents of 4 main functional components and antioxidant activity were significantly different between the stem,leaf and flower from D.officinale,the polysaccharide of leaf and flower were lower than that observed in stem:Stem(31.00%)>Leaf(15.04%)>Flower(8.11%);However,compared with stem,the total flavonoid,total polyphenol and total alkaloids contents of leaf and flower were much higher.The results of DPPH,ABTS,FRAP analyses all indicated that the D.officinale stem,leaf and flower all exhibited a great antioxidant activities,the flower approached that of vitamin C(V C)at specific concentrations,the alcohol extract of leaf exhibited a higher antioxidant capacity than stem,The antioxidant activity of the samples increased positively with the concentration.According to correlation analysis,the total phenols and flavonoids have the strongest contribution to the antioxidant capacity(P<0.01),total alkaloid has stronger contribution to the antioxidant capacity(P<0.05).Conclusion:This study provided guidance for the comprehensive development and utilization of D.officinale.