The chemical or metabolic compositions of tea (Camellia sinensis) varies according to numerous factors, such as geographical origin, cultivar, climate, plucking position, and horticultural practices. However, how the age of tea plants affects the metabolite compositions of tea leaves has not been reported yet. Therefore, we extended the metabolomic approach to the investigation of the age-related differences of tea leaf metabolites in the fresh leaves collected from tea plants aged 8 and 25 years. Multivariate statistical analysis with comprehensive metabolite profiles analyzed by 1H NMR spectroscopy showed the clear metabolic differentiation between the fresh tea leaves from different ages of the tea plants. Of the various tea leaf metabolites varied according to the age of the tea plants, theanine, glutamine, catechin, and gallocatechin were uniquely dependent on the age of tea plants, demonstrating a difference of theanine metabolism between young and old tea plants. These results suggest that leaves from 25-year-old tea plants would still be worthy as a functional ingredient for the production in the food or cosmetic industry rather than quality-enhanced tea infusions for human consumption.

中文翻译：

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茶叶的表征代谢物依赖于茶（茶树）植物通过年龄¹基于NMR-H代谢

茶（茶树）的化学或代谢成分会因多种因素而异，例如地理来源，品种，气候，采摘位置和园艺习惯。然而，尚未报道茶树的年龄如何影响茶叶的代谢产物组成。因此，我们将代谢组学方法扩展到调查年龄在8和25岁的茶树中的新鲜叶片中茶叶代谢产物的年龄相关差异研究。通过1H NMR光谱分析对代谢物进行全面分析的多变量统计分析表明，茶树不同年龄的新鲜茶叶之间存在明显的代谢差异。在各种茶叶代谢物中，茶氨酸，茶氨酸，谷氨酰胺，儿茶素，茶树素和加水儿茶素独特地依赖于茶树的年龄，这表明年轻茶树和老茶树之间的茶氨酸代谢存在差异。这些结果表明，具有25年历史的茶树的叶子仍然值得作为食品或化妆品行业生产的功能成分，而不是供人食用的质量增强的茶汁。