Multivariate analysis of H-1 NMR spectra for saponins from Quillaja saponaria Molina

The bark of the South American tree Quillaja saponaria Molina contains at l east 100 different saponin structures. A set of known structures were class ified by partial least squares regress ion-discriminant analysis (PLS-DA) o n spectra from H-1 NMR. PLS-DA was found to detect structural variations in the different parts of the saponins, encoded in the spectra. The models ob tained were used to classify a test set of known structures. The amount of saponin material used for the NMR spectroscopy was only 200 m ug/sample. This means that the outlined method is an interesting tool in th e structural analysis of minor saponin components from Quillaja. This non-d estructive method could also be applied on and facilitate the analysis of o ther natural products and metabolites since only minor amounts of sample ar e needed. (C) 2001 Elsevier Science B.V. All rights reserved.