Metabolism of gartanin in liver microsomes and its modulating effects on cytochrome P450s

Gartanin, a compound found in mangosteen, has various pharmacological activities, including anticancer, anti-inflammation, and antioxidation.In the present study, we reported differences of gartanin metabolism among species and the effect of gartanin on cytochrome P450 (CYP) activities and protein expression.We found significant difference in gartanin metabolism among species, where rabbits and humans had similar metabolic characteristics. Five CYP-catalysed metabolites and three glucuronosyltransferase (UGT)-catalysed metabolites were identified by LC-MS/MS. Hydroxylation was the major metabolic pathway. Gartanin exhibited mixed inhibition on CYP1A2 activity with IC50 and Ki values of 1.48 and 3.71 μM, respectively. In addition, gartanin down-regulated the protein expressions of CYP2C9 and CYP2D6 and up-regulated the protein expression of CYP2D6. The present study supports the pharmacological and toxicological research of gartanin.