Characterization and antioxidant activity of green tea (Camellia sinensis) using ¹H NMR-based metabolomics

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Nuclear magnetic resonance (NMR) spectroscopy is a well-known analytical tool for structure determination of small and macro molecules. Recently, it has been also used for quantitative analysis (qNMR) and metabolomics with multivariate statistics. In this study, we evaluated the comprehensive assessment of green tea using the NMR techniques including qNMR and principal component analysis (PCA), and the functional elucidation. Thirty-five samples of green tea collected from five countries were extracted with hot water, and then the green tea samples were analyzed by their ¹H NMR. The major constituents in green tea including caffeine, catechins (EC, EGC, ECg, and EGCg), sugars (glucose, sucrose, and arabinopyranosyl-myo-inositol), and theanine were assigned and quantified using ¹H NMR signals. PCA was performed on the ¹H NMR data. Based on the results obtained, the 35 types of green tea were established to be clearly distinguished according to their countries of origin and harvest season.