Identification of new metabolites of morroniside produced by rat intestinal bacteria and HPLC-PDA analysis of metabolites in vivo

Morroniside, the most abundant iridoid glycoside of traditional Chinese medicines Fructus Corni, was shown to prevent diabetic angiopathies. During the course of our studies on its metabolism by intestinal bacteria, two metabolites (mor-1 and mor-2) were isolated and purified by thin layer chromatography (TLC) and preparative high performance liquid chromatography (HPLC), and then identified as nitrogen-containing compounds along with the known aglycones on the basis of mass spectrometry (MS), and by one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy. Mor-1 and mor-2 were proved to be new compounds. The structures of the metabolites of morroniside detected in rat urine, bile, feces and contents of intestine after oral administration of morroniside proved to be identical with those of the microbial metabolites mor-1 and mor-2.