LC-MS/MS Method Development and Validation for the Determination of Ilexsaponin A1 and Its Application in Intestinal Bacterial Metabolic Study

Background: Ilexsaponin A1, one of the most representative triterpene saponin components in the roots of I. pubescens, showed its effects in anticoagulation and antithrombosis, attenuating ischemia-reperfusion-induced myocardial, angiogenesis and inhibiting phosphodiesterase. Objective: Reveal the key intestinal bacterial strains responsible for ilexsaponin A1 metabolism, and clarify their metabolic behavior. Methods: An accurate and sensitive LC-MS/MS method for the determination of “ilexsaponin A1 in General Anaerobic Medium (GAM) broth” was established and systematically validated. Then it was applied to screen and study the metabolic potential of the intestinal bacterial strains in an anaerobic incubation system. Results: Quantitation of ilexsaponin A1 could be performed within an analytical run time of 14.5 min, in the linear range of 2 - 2000 ng/ml. Enterobacter sakazakii, Bifidobacterium breve, Bifidobacterium adolescentis, Bifidobacterium catenulatum, and Bifidobacterium angulatum were identified to have a potential effect to metabolize ilexsaponin A1 to different extents; and further bacterial metabolic studies were performed to clarify their metabolic capacity and behavior. Conclusion: This paper contributes to a better understanding of the intestinal bacterial metabolism of ilexsaponin A1 and provides scientific evidence for its clinical application. Additionally, the importance of intestinal bacterial strains in the disposition of natural products was also highlighted.