Identification of the metabolites of erianin in rat and human by liquid chromatography/electrospray ionization tandem mass spectrometry.

RATIONALE

Erianin, a bioactive component isolated from Dctidrobium chrysotoxum Lindl, was demonstrated to have many biological properties relevant to cancer prevention and therapy. However, the metabolic profiles of erianin remain unknown. This study was carried out to investigate the metabolic profiles of erianin in rats and humans.

METHODS

Erianin was orally administered to rats at a single dose of 50 mg/kg. Urine and bile samples were collected. For in vitro metabolism, erianin was co-incubated with rat or human hepatocytes at 37°C for 2 h. The samples from incubations and rat were analyzed by liquid chromatography combined with electrospray ionization high-resolution mass spectrometry. The data were processed by MetWorks software. The structures of the metabolites were proposed by comparing the mass spectra with that of the parent compound.

RESULTS

A total of twenty-four metabolites were detected in vitro and in vivo, including seven phase I and eighteen phase II metabolites. The phase I metabolic pathways of erianin were hydroxylation, demethylation and dehydrogenation. Erianin undergoes metabolic activation to form reactive metabolites quinoid intermediates, which were further trapped by glutathione (GSH) or N-acetylcysteine. The phase II metabolic pathways were glucuronidation, glutathione and N-acetylcysteine conjugation.

CONCLUSIONS

The present study provides an overview pertaining to the in vitro and in vivo metabolic profiles of erianin, which is indispensable for us to understand the efficacy and safety of erianin, as well as the herbal medicine D. chrysotoxum.