Novel quantitative method for sapogenins in yucca extracts by gas chromatography tandem mass spectrometry

The p-anisaldehyde reaction with yucca extract saponins has long been utilized for semi-quantitating saponins or sapogenins by reaction product UV–visible spectroscopy, likely by reaction with compound ketal functions. The methodology was easily implemented and enabled direct comparison with a new detection method generated from gas chromatography-tandem mass spectrometric (GC/MS/MS) analysis of yucca extracts prepared by a new hydrolytic method. The GC/MS/MS method was validated for properties of linearity, specificity, precision, and accuracy. The p-anisaldehyde/UV–visible approach operated well with or without hydrolysis, unlike the GC/MS/MS approach that relied on yucca extract hydrolysis. Nevertheless, the GC/MS/MS approach correlated well with the p-anisaldehyde/UV–visible method to a coefficient of determination of 0.8, despite the finding that the p-anisaldehyde/UV–visible method overestimated concentrations perhaps by as much as 1.7x. Reasons are discussed as to why this likely represents an overestimate by the p-anisaldehyde/UV–vis method. Yucca extracts predominantly contained smilagenin/sarsasapogenin epimeric pairs as well as smaller amounts of hecogenin and an epimer dubbed epi-hecogenin. Fifteen or more additional sapogenin compounds were also observed, but on average accounted for no more than 15% of the total composition of sapogenins.