School of Life Science and Biotechnology, Korea University , Seoul 136-701, Republic of Korea.
J Agric Food Chem. 2011 Oct 12;59(19):10579-85. doi: 10.1021/jf202304z. Epub 2011 Sep 16.
The dependence of global green tea metabolome on plucking positions was investigated through (1)H nuclear magnetic resonance (NMR) analysis coupled with multivariate statistical data set. Pattern recognition methods, such as principal component analysis (PCA) and orthogonal projection on latent structure-discriminant analysis (OPLS-DA), were employed for a finding metabolic discrimination among fresh green tea leaves plucked at different positions from young to old leaves. In addition to clear metabolic discrimination among green tea leaves, elevations in theanine, caffeine, and gallic acid levels but reductions in catechins, such as epicatechin (EC), epigallocatechin (EGC), epicatechin-3-gallate (ECG), and epigallocatechin-3-gallate (EGCG), glucose, and sucrose levels were observed, as the green tea plant grows up. On the other hand, the younger the green tea leaf is, the more theanine, caffeine, and gallic acid but the lesser catechins accumlated in the green tea leaf, revealing a reverse assocation between theanine and catechins levels due to incorporaton of theanine into catechins with growing up green tea plant. Moreover, as compared to the tea leaf, the observation of marked high levels of theanine and low levels of catechins in green tea stems exhibited a distinct tea plant metabolism between the tea leaf and the stem. This metabolomic approach highlights taking insight to global metabolic dependence of green tea leaf on plucking position, thereby providing distinct information on green tea production with specific tea quality.
通过（1）H 核磁共振（NMR）分析结合多元统计数据集，研究了全球绿茶代谢组对采摘位置的依赖性。采用主成分分析（PCA）和偏最小二乘判别分析（OPLS-DA）等模式识别方法，对不同位置（从嫩叶到老叶）采摘的新鲜绿茶叶片进行代谢差异分析。除了对绿茶叶片的代谢差异有明显的认识外，还观察到茶氨酸、咖啡因和没食子酸水平的升高，儿茶素（如表儿茶素（EC）、表没食子儿茶素（EGC）、表儿茶素-3-没食子酸酯（ECG）和表没食子儿茶素-3-没食子酸酯（EGCG）、葡萄糖和蔗糖水平的降低，随着绿茶植物的生长而升高。另一方面，绿茶叶片越年轻，茶氨酸、咖啡因和没食子酸积累越多，儿茶素积累越少，这表明由于茶氨酸与儿茶素结合，随着绿茶植物的生长，茶氨酸与儿茶素水平呈反向关联。此外，与茶叶相比，在绿茶茎中观察到茶氨酸含量高，儿茶素含量低，这表明茶叶和茎之间存在明显的茶树代谢差异。这种代谢组学方法强调了对全球绿茶叶片对采摘位置的代谢依赖性的深入了解，从而为具有特定茶叶品质的绿茶生产提供了独特的信息。
