Metabolism of Gallic Acid and Its Distributions in Tea (Camellia sinensis) Plants at the Tissue and Subcellular Levels.

Xiaochen Zhou,Yinyin Liao,Xiumin Fu,Lanting Zeng,Xuewen Wang,Yangyang Xiao,Yingjuan Chen,Ziyin Yang

doi:10.3390/ijms21165684

Abstract

In tea (Camellia sinensis) plants, polyphenols are the representative metabolites and play important roles during their growth. Among tea polyphenols, catechins are extensively studied, while very little attention has been paid to other polyphenols such as gallic acid (GA) that occur in tea leaves with relatively high content. In this study, GA was able to be transformed into methyl gallate (MG), suggesting that GA is not only a precursor of catechins, but also can be transformed into other metabolites in tea plants. GA content in tea leaves was higher than MG content—regardless of the cultivar, plucking month or leaf position. These two metabolites occurred with higher amounts in tender leaves. Using nonaqueous fractionation techniques, it was found that GA and MG were abundantly accumulated in peroxisome. In addition, GA and MG were found to have strong antifungal activity against two main tea plant diseases, Colletotrichum camelliae and Pseudopestalotiopsis camelliae-sinensis. The information will advance our understanding on formation and biologic functions of polyphenols in tea plants and also provide a good reference for studying in vivo occurrence of specialized metabolites in economic plants.

Highlights

Tea is a beverage made from the tender leaves of tea plant (Camellia sinensis (L.) O
The occurrences of gallic acid (GA) and its derivative at the individual plant level, tissue level and subcellular level were investigated, using mass spectrometry and nonaqueous fractionation (NAF) techniques. According to their occurrences and distributions, we evaluated if GA and its derivative have direct antifungal activity in vitro against the main diseases of tea plants, namely, Colletotrichum camelliae and Pseudopestalotiopsis camelliae-sinensis
Physiological state of tea leaves was in a good condition because of continuous water supply

Summary

Introduction

Tea is a beverage made from the tender leaves of tea plant (Camellia sinensis (L.) O. Kuntze) and has attained considerable popularity owing to its health benefits and good quality [1] These tea characteristics result from the occurrence of tea metabolites, such as polyphenol, l-theanine, caffeine and aroma compounds [1,2,3]. Many researchers have focused on the relationships of tea metabolites with tea quality and function [1,4] Among these metabolites, the content of polyphenols is relatively high, accounting for 18%–36% of tea (dry weight), so they have been studied in-depth [4]. Numerous studies have investigated their contribution to tea quality and human health and metabolism and biologic functions in tea plants. Study on GA distribution in leaves during tea plant growth may help to reveal its potential biologic functions. It is not clear that whether GA can be converted into other derivatives in tea plants

Objectives

Methods

Results

Conclusion