广西不同产地绿茶中主要抗氧化物质含量及其抗氧化活性分析

Analysis of the Contents and Activities of Main Antioxidant Substances in the Green Teas from Different Production Regions in Guangxi

摘要:

通过高效液相色谱法检测咖啡碱和表没食子儿茶素等10种主要抗氧化活性物质含量差异，并利用DPPH自由基清除率、羟自由基清除率和总抗氧化能力综合评价其抗氧化能力，探究广西不同产地绿茶化学成分和抗氧化间的关系。结果显示，茶叶中咖啡碱的含量在17.08~37.16 mg/g；可可碱含量在5 mg/g左右；茶碱含量较低（0~0.47 mg/g）；表没食子儿茶素含量在10~20 mg/g；表没食子儿茶素没食子酸酯的含量较高，含量在50 mg/g左右；表儿茶素没食子酸酯含量差异较大，含量在2.14~21.2 mg/g；表儿茶素含量在5 mg/g左右；没食子酸和没食子儿茶素没食子酸酯的含量较低（≤5 mg/g）；没食子儿茶素含量基本在2 mg/g以下。结合相似度评价和聚类分析结果，产地位于广西高纬度、中纬度地区的绿茶高度相似，可明显与低纬度的绿茶区分。茶叶的DPPH自由基清除率均在60%以上；羟自由基清除率在1.68%~85.38%之间；总抗氧化能力在1.644~3.608 mmol/g范围内。综合表明广西绿茶普遍具有较好的抗氧化活性，且多酚含量与抗氧化活性呈正比例关系，该研究为广西绿茶的品质评价和差异化分析提供数据基础。

Abstract:

Through detecting the differences in the contents of 10 main antioxidant substances, including caffeine and epigallocatechin gallate, using high-performance liquid chromatography (HPLC), and evaluating their antioxidant capacities comprehensively based on DPPH radical scavenging rate, hydroxyl radical scavenging rate, and total antioxidant capacity, this study explored the relationship between the chemical composition and antioxidant capacity of the green teas from different origins in Guangxi. The results showed that that the green teas had a content of caffeine between 17.08 and 37.16 mg/g, content of theobromine around 5 mg/g, low content of theophylline between 0 and 0.47 mg/g, content of epigallocatechin gallate between 10 and 20 mg/g, high content of epigallocatechin gallate around 50 mg/g, varying content of epicatechin gallate in the range of 2.14~21.2 mg/g, content of epicatechin around 5 mg/g, contents of gallic acid and epigallocatechin gallate not higher than 5 mg/g, and content of epigallocatechin gallate essentially below 2 mg/g. Combining the results of similarity evaluation and clustering analysis, the green teas from the high- and mid-latitude regions of Guangxi were highly similar, and could be distinctly distinguished from those of the low-latitude regions. The DPPH radical scavenging rates of all teas were above 60%; the hydroxyl radical scavenging rates ranged from 1.68% to 85.38%; the total antioxidant capacities were between 1.644 and 3.608 mmol/g. Overall, the green teas from Guangxi possess good antioxidant activities on average, and there was a positive correlation between the content of polyphenols and antioxidant activity. This study provides a data foundation for the quality evaluation and differential analysis of Guangxi green teas.