Metabolic and Pharmacokinetic Investigation of Ilexsaponin A1 in Normal and Antibiotic-treated Rats

Background: Ilexsaponin A(1) (IA(1)) is a bioactive triterpene saponin derived from natural medicinal plants. IA(1) exhibits anti-inflammatory and proangiogenic activities and improves intestinal barrier function. It has been reported that IA(1) could be metabolized into a dominant metabolite, ilexgenin A (IA) by beta-glucosidase enzymes in intestinal microflora.Materials and Methods: Herein, an accurate, sensitive, and selective method based on ultra-performance liquid chromatography coupled with mass spectrometry was established to simultaneously profile the metabolism and pharmacokinetic behaviors of IA(1) in normal and antibiotic-treated rat plasma after intragastric administration of IA(1). The precursor-to-product ion pairs of IA and IA(1) were m/z 501.32 -> 439.32 and m/z 663.38 -> 501.32, respectively. For method validation, the specificity, matrix effect, accuracy, precision, and stability of the pharmacokinetic study were measured, and a calibration curve was created. The collaborative pharmacological target pathways of IA(1) and its metabolite IA were investigated using network pharmacology tools.Results: The validated analytical method was successfully utilized to investigate the pharmacokinetics of IA(1) in normal and antibiotic-treated rats. The bioavailability of IA1 and conversion from IA(1) to IA were significantly inhibited by antibiotic-treated rats after oral administration of IA(1). Fragment ions at m/z 483.3155, 455.3159, 439.3233, 421.3136, 395.3362, 152.9952, 113.0256, and 71.0531 were characteristic of the IA(1) moiety. IA(1) was metabolized in rat plasma by biotransformation routes involving deglycosylation, decarboxylation, isomerization, hydrogenation, dehydrogenation, and oxidation. Considering database analysis, IA and IA(1) play synergistic role in common pharmacological pathways, such as hypertrophic cardiomyopathy and dilated cardiomyopathy.Conclusion: The experiments illustrated that beta-glucosidase activity inhibited by antibiotics suppressed the hydrolysis reaction of IA(1) in the intestinal tract. IA(1) and IA play a synergistic role in exerting effects.