Determination of pharmacokinetics of chrysin and its conjugates in wild-type FVB and Bcrp1 knockout mice using a validated LC-MS/MS method.

Chrysin, a flavone found in many plants, is also available as a dietary supplement because of its reported anticancer activities. However, its bioavailability is very poor due to extensive phase II metabolism. The purpose of this study was to develop an UPLC-MS/MS method to simultaneously quantify chrysin and its phase II metabolites, and to determine its pharmacokinetics in FVB wild-type and Bcrp knockout (Bcrp1 -/-) mice. In addition, the role of BCRP in chrysin phase II disposition was further investigated in Caco-2 cells. The results showed that our sensitive and reproducible UPLC-MS/MS method was successfully applied to the pharmacokinetic study of chrysin in wild-type and Bcrp1 (-/-) FVB mice after oral administration (20 mg/kg). Although there was no significant change in systemic exposure of chrysin and its metabolites, it was found that the Tmax for chrysin glucuronide was significantly shorter (p < 0.01) in Bcrp1-deficient mice. Furthermore, it was shown that inhibition of BCRP by Ko143 significantly reduced the efflux of chrysin sulfate in Caco-2 cells. In conclusion, BCRP had significant but less than expected impact on pharmacokinetics of chrysin and its conjugates, which were determined using a newly developed and validated LC-MS/MS method.