Metabolomic analysis of Strychnos nux-vomica, Strychnos icaja and Strychnos ignatii extracts by super(1)H nuclear magnetic resonance spectrometry and multivariate analysis techniques

super(1)H Nuclear magnetic resonance spectrometry and multivariate analysis techniques were applied for the metabolic profiling of three Strychnos species: Strychnos nux-vomica (seeds, stem bark, root bark), Strychnos ignatii (seeds), and Strychnos icaja (leaves, stem bark, root bark, collar bark). The principal component analysis (PCA) of the super(1)H NMR spectra showed a clear discrimination between all samples, using the three first components. The key compounds responsible for the discrimination were brucine, loganin, fatty acids, and Strychnos icaja alkaloids such as icajine and sungucine. The method was then applied to the classification of several 'false angostura' samples. These samples were, as expected, identified as S. nux-vomica by PCA, but could not be clearly discriminated as root bark or stem bark samples after further statistical analysis.