Metabolic Discrimination of Rhizoma Coptidis from Different Species Using 1H NMR Spectroscopy and Principal Component Analysis

Rhizoma Coptidis, a broadly used medicinal plant, originates from the dried rhizomes of three species in Chinese pharmacopoeia, namely, Coptis chinensis Franch, Coptis deltoidea C.Y. Cheng et Hsiao, and Coptis teeta Wall. In this study, a novel approach using H-1 NMR spectroscopy combined with multivariate analysis was introduced to differentiate the three species and identify potential metabolic markers for better controlling the quality of Rhizoma Coptidis. A broad range of metabolites including alkaloids, sugars, organic acids, amino acids, and fatty acids present in Rhizoma Coptidis were detected by means of H-1 NMR spectroscopy. Principal component analysis (PCA) of the H-1 NMR data set showed a clear separation between all samples by PC1 and PC3, and some metabolites that could be responsible for the discrimination of the three species were identified. An analysis of variance (ANOVA) was performed to statistically verify the significance of differences in metabolite levels between species. By combining PCA and ANOVA, significantly higher contents of palmatine, coptisine, epiberberine, columbamine, and fatty acids together with lower contents of jateorrhizine were found in Coptis chinensis, whereas Coptis deltoidea and Coptis teeta showed the highest levels of sucrose and chlorogenic acid, respectively. This study indicates that metabolites of Rhizoma Coptidis vary with the species and the proposed method is suitable for metabolic fingerprinting analysis to check the genuine origin of Rhizoma Coptidis.