Detection and Confirmation of Ginsenosides in Horse Urine by GC-MS and LC-MS

Ginseng has been used by the Chinese as a traditional herbal medicine for thousands of years. In view of the growing popularity in the use of ginseng preparations as natural remedies and food supplements worldwide, there is an increasing concern for their abuse in both human and animal sports. Ginsenosides are considered the major constituents of ginseng responsible for its pharmacological properties. In this study, a method was developed for the detection and confirmation of a number of ginsenosides in horse urine. The intact ginsenosides were detected and confirmed at 5-100 ng mL(-1) by LC-MS2, and two deglycosylation metabolites, namely protopanaxadiol and protopanaxatriol, could both be detected and confirmed at 2 ng mL(-1) by GC-MS2 after trimethylsilylation. The above GC-MS and LC-MS methods were then applied to study the in vitro metabolism of ginsenosides Rg1 and Rb1 and the in vivo urinary metabolites after oral administration of Rg1 to horses. Results obtained reveal the very first evidence for the existence of the metabolites, Rg1 and protopanaxatriol, as glucuronides in urine.