RESUMO
<p><b>OBJECTIVE</b>To study the rat intestinal bacteria metabolism of total saponins of Dioscorea pathaica (TSDP) in vitro, and characterize the metabolites in serum and urine of rats after oral administration of TSDP 900 mg.kg-1.</p><p><b>METHOD</b>TSDP metabolites were detected with thin-layer chromatography (TLC) and combination of electrospray ionization mass spectrometry (ESI-MS) and sequential tandem mass spectrometry (MSn).</p><p><b>RESULT</b>In vitro, TSDP was decomposed easily by rat intestinal bacteria, and metabolites DP-1, DP-2, DP-4, DP-5 and diosgenin (Dio) were observed with prolongation of incubation time by ESI-MS2. In vivo, in the full-scan positive mass spectrum of the rat urine sample, the ion peak at m/z 415 (M-H) and its characteristic fragmentations at m/z 397 and m/z 271 in the MS/MS spectrum were identified with that of metabolite Dio, therefore metabolite Dio was deduced to exist in the rat urine, and metablite Dio was allso detected in the rat serum sample.</p><p><b>CONCLUSION</b>TSDP is decomposed easily by rat intestinal bacteria and metabolite diosgenin is absorbed into blood after oral administration of TSDP.</p>