信阳红红茶的酚类成分及抗氧化能力分析

Analysis of Phenols and Antioxidant Capacity of Xinyanghong Black Tea

为探究信阳红红茶的酚类成分及其抗氧化能力,该文采用高效液相色谱(high performance liquid chromatography,HPLC)等方法对9个信阳红红茶中8种儿茶素、6种黄酮类、2种酚酸和水解单宁等酚类成分以及3种嘌呤碱进行定量检测;并采用5种不同方法分别检测分析红茶茶样的体外抗氧化能力。结果表明,在全部或部分信阳红红茶中共检出除没食子儿茶素外的所有酚类成分和3种嘌呤碱。单因素方差分析显示,9个信阳红红茶中部分茶样之间茶多酚、3种茶色素(茶黄素、茶红素和茶褐素)、7种儿茶素、没食子酸、3种黄酮类(花旗松素、槲皮素和山奈酚)、可可碱和水解单宁含量存在极显著性(P<0.001)差异,以及铁离子还原抗氧化能力(ferric ion reducing antioxidant power,FRAP)、DPPH自由基清除能力和超氧阴离子自由基清除能力(superoxide anion radical scavenging ability,SSA)的体外抗氧化能力存在显著性差异(P<0.01)。信阳红红茶中表儿茶素没食子酸酯含量最高,其次依次为表没食子儿茶素没食子酸酯、表儿茶素和表没食子儿茶素等儿茶素。芦丁、花旗松素和木犀草素为主要黄酮类化合物,其含量分别为1.39 mg/g~1.79 mg/g、0.59 mg/g~0.74 mg/g和0.53 mg/g~0.75 mg/g。双变量相关性分析显示儿茶素、没食子酸等酚类成分以及茶黄素与FRAP、DPPH自由基清除能力、ABTS+自由基清除能力存在显著(P<0.05)或高显著(P<0.01)正相关性,在一定程度上能提高红茶的体外抗氧化能力。

This study aims to explore the phenols in Xinyanghong black tea and their impact on antioxidant capacity of the tea.To be specific,high performance liquid chromatography(HPLC)was developed to determine phenols(8 catechins,6 flavonoids,2 phenolic acids,and hydrolysable tannins)and 3 purine alkaloids in 9 Xinyanghong black tea samples.In addition,the in vitro antioxidant activities of the samples were determined with 5 methods.Results showed that except for gallocatechin(GC),other phenols and 3 purine alkaloids were detected in all or some of Xinyanghong black tea samples.One-way analysis of variance demonstrated significant difference(P<0.001)in tea polyphenols,3 tea pigments(theaflavins,thearubigins,and theabrownins),7 catechins,gallic acid,3 flavonoids(taxifolin,quercetin,and kaempferol),theobromine,and hydrolysable tannins,as well as the significant difference(P<0.01)in ferric reducing antioxidant power(FRAP),DPPH-scavenging activity,and superoxide anion scavenging ability(SSA)among some of the 9 tea samples.Epicatechin gallate was the main catechin in teas,followed by epigallocatechin gallate,epicatechin and epigallocatechin.Rutin,taxifolin and luteolin were main flavonoids with the content of 1.39 mg/g-1.79 mg/g,0.59 mg/g-0.74 mg/g and 0.53 mg/g-0.75 mg/g,respectively.Bivariate correlation analysis showed significant(P<0.05)or highly significant(P<0.01)positive correlation of phenols including catechins and gallic acid,and theaflavins with FRAP,DPPH-scavenging activity and ABTS+-scavenging activity,which could improve the in vitro antioxidant activity of black tea.