Multivariate analysis of 1H NMR spectra for saponins from Quillaja saponaria Molina Original Research Article

The bark of the South American tree Quillaja saponaria Molina contains at least 100 different saponin structures. A set of known structures were classified by partial least squares regression-discriminant analysis (PLS-DA) on spectra from 1H NMR. PLS-DA was found to detect structural variations in the different parts of the saponins, encoded in the spectra. The models obtained were used to classify a test set of known structures. The amount of saponin material used for the NMR spectroscopy was only 200 μg/sample. This means that the outlined method is an interesting tool in the structural analysis of minor saponin components from Quillaja. This non-destructive method could also be applied on and facilitate the analysis of other natural products and metabolites since only minor amounts of sample are needed.