中国典型砖形黑茶非挥发物的代谢组学分析

Metabolomics of Non-volatiles in Typical Chinese Brick Dark Tea

为探究我国典型砖形黑茶代谢物轮廓的规律,以及砖形黑茶与黑茶真菌在代谢物种类方面的关系,本研究利用基于液相色谱-质谱联用的非靶向代谢组学和基于特征物信息的质谱分子网络技术,对我国典型的砖形黑茶(湖北青砖茶、四川康砖茶、湖南的黑砖茶、花砖茶和茯砖茶、陕西的茯砖茶)以及茶鲜叶和分离自黑茶的多种真菌进行代谢组学分析。结果表明,砖形黑茶的非挥发性代谢物轮廓更倾向于按照生产地区进行分类,一组是来自湖南和陕西的砖形黑茶,而另一组是来自四川和湖北的砖形黑茶;决定其代谢物轮廓分组的最主要因素是砖茶含梗率,来自四川和湖北的砖形黑茶含梗率明显高于另一组;造成两组砖形黑茶轮廓差异的主要原因是湖南和陕西的砖形黑茶中有更高含量的黄烷-3-醇类和大部分氨基酸及其衍生物等代谢物;针对砖形黑茶和真菌代谢物的分子网络分析发现,在砖形黑茶中,尤其是在康砖茶中广泛分布着源自真菌的线性和环状二肽;在茯砖茶中有着结构种类丰富的异戊烯基二酮哌嗪类化合物,这类化合物来自于冠突散囊菌,因此,真菌为砖形黑茶贡献了种类丰富的代谢物。本实验结果可为全面了解和认识我国典型砖形黑茶的化学物质基础提供理论参考。

To investigate the metabolite profiles of typical Chinese brick dark tea and the relationship between the metabolite types of brick dark tea and fungi isolated from it,this study used non-targeted metabolomics based on liquid chromatography-mass spectrometry(LC-MS)and feature-based molecular networking(FBMN)for metabolomic analysis of typical brick dark tea in China(Hubei Qingzhuan brick tea,Sichuan Kangzhuan brick tea,dark brick tea,Huazhuan brick tea and Fuzhuan brick tea from Hunan,and Fuzhuan brick tea from Shaanxi),fresh tea leaves and various fungal strains isolated from dark tea.The results indicated that the non-volatile metabolite profiles of brick dark tea tended to be classified into two groups according to production regions:one group included brick dark tea from Hunan and Shaanxi,and the other group included brick dark tea from Sichuan and Hubei.The major factor determining the metabolite profile was the stalk percentage of brick tea,and the stalk percentage of brick dark tea from Sichuan and Hubei was significantly higher than that of the other group.The major reason for the difference in metabolite profile between the two groups was the higher contents of flavan-3-ols as well as most amino acids and their derivatives in brick dark tea from Hunan and Shaanxi.The molecular network analysis of the metabolites of brick dark tea and fungi showed that linear and cyclic dipeptides derived from fungi were widely distributed in brick dark tea,especially Kangzhuan brick tea.Isopentenyl diketopiperazine compounds of diverse structural types were found to be abundant in Fuzhuan brick tea,which were derived from Eurotium cristatum.Therefore,fungi contribute to the rich variety of metabolites in brick dark tea.This research can provide a theoretical reference for a comprehensive understanding and knowledge of the chemical basis of quality in typical brick dark tea in China.