Elucidation of the Structures of Metabolites of Picroside II in Rat Bile by LC–ESI–IT–MS

Abstract

Picroside II is one of the main active constituents of Picrorhiza kurroa, which has hepatoprotective, anticholestatic, antioxidant, and immune-modulating activity. To gain an understanding of the biotransformation of picroside II in vivo, liquid chromatography-electrospray ionization ion-trap mass spectrometry (LC-ESI-IT-MS) was used to investigate the metabolism of picroside II in rats after intravenous administration of a single dose. This method could simultaneously determine picroside II and its metabolites in rat bile. The bile samples were purified by use of a C 18 solid-phase extraction (SPE) cartridge and were separated on a Hypersil ODS2 C 18 analytical column. Two phase II metabolites of picroside II in rat bile were characterized, and elucidation of their structures was performed by comparing changes in molecular masses (DM), retention times, and MS 2 spectral patterns of metabolites with those of the parent drug. Two metabolites identified for the first time in this research were glucuronide and sulfate conjugates.

In Vitro and in Vivo Metabolism of Verproside in Rats

“…These results indicate that M7 and M8 may be M5 (picroside II) glucuronide and M6 (isovanilloylcatalpol) glucuronide, respectively, but the position of glucuronidation was not accurately identified. These results support the results of Li et al [ 10 ] that identified picroside II glucuronide in the bile samples obtained after intravenous administration of picroside II in rats.…”

“…Sulfatase treatment of the bile and urine samples increased the peak areas of M5 (picroside II) and M6 (isovanilloylcatalpol), but decreased the M9 and M10 peaks. These results indicate that M9 and M10 might be M5 (picroside II) sulfate and M6 (isovanilloylcatapol) sulfate, respectively, supporting the result of Li et al [ 10 ] that showed picroside II was metabolized to picroside II sulfate as well as picroside II glucuronide in rats.…”

Characterization of picroside II metabolites in rats by ultra-high-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight tandem mass spectrometry

“…M01, M02 and M09 were found as the circulating metabolites in rat plasma, which may be associated with its activity. Although the biotransformation on picroside II have been reported in previous studies [23][24], our observations provided insights into the in vivo disposition of picroside II as a total of six metabolites were newly identified (M03-M08). Further studies should focus on the preparation of the newly identified principal metabolites and the evaluation of their hepatoprotective effects and toxicities.…”

Unique biocatalytic resolution of racemic tetrahydroberberrubine via kinetic glycosylation and enantio-selective sulfation

“…To confirm this M3 was incubated with sulfatase, 10 which hydrolyzed M3 into (+)À1. The NMR (both 1 H and 13 C) of (+)À1, which was obtained via the action of sulfatase on M3 was identical to that of (À)À1, which was obtained via the hydrolysis of M1 (see Scheme 1).…”