An enzymatic protocol for absolute quantification of analogues: application to specific protopanoxadiol-type ginsenosides

Abstract

Comprehensive quantification of a specific class of natural products using liquid chromatography tandem mass spectrometry with greener approaches is of significant importance. In this study, a green protocol was proposed for determining analogues with a small number of reference standards. The protocol was conducted by combining the chromatography-based fraction collection, the calibration curve matrix materials and the identical enzymatic hydrolysate. This strategy can accurately calibrate the concentration ratios and successfully calculate the relative response factors (F) of the specific protopanoxadiol-type ginsenosides. The recoveries of all fractions were monitored by the modified non-standard recovery evaluation strategy rather than the commonly used method with total reference standards. Coupled with the calculated F, the quantitative analysis of multi-components with a single marker was successfully applied to simultaneously determine the analogues of interest in Sanqi (Panax notoginseng) extract. The use of snailase for quantification of ginsenosides especially in application to the commercially unavailable ginsenoside Rd isomer was reported for the first time. By consuming less solvent and fewer reference standards, the developed green protocol facilitates its application to other analogues in herbal and food samples by utilizing suitable enzymes or derivative techniques.