Stability kinetics of ginsenosides in aqueous solution.

The stability of ginsenosides (Rb1, Rb2, and Rg1) in aqueous solutions of varying pH was studied kinetically at 37 degrees C and an ionic strength of 0.15, using reverse-phase high-performance liquid chromatography. Degradation readily occurred by a proton-catalyzed reaction, the half-lives being only approximately 30 min at pH 1. However, under neutral intestinal pH conditions, the degradation was almost negligible throughout the experimental period (approximately 40 h).