An LC-ESI/MS/MS method for the determination of lupeol via precolumn derivatization and its application to pharmacokinetic studies in rat plasma

Lupeol, a phytosterol and triterpene, is widely found in edible fruits and vegetables, and has been reported to exhibit a spectrum of pharmacological activities against various disease conditions. In the present study, a derivative generated by the reaction of lupeol with p-toluenesulfonyl isocyanate was ionizable and fragmentable in the negative mode by electrospray ionization/tandem mass spectrometry. Based on this simple chemical derivatization, a liquid chromatography-electrospray ionization/tandem mass spectrometry method was developed and validated for the quantification of lupeol in rat plasma. The calibration curves were linear (r(2) > 0.999) over concentrations from 2.5 to 250 ng/ml for lupeol. The method had an accuracy of 96.0-109.4%, and the intra- and inter-day precisions (RSD) were within +/- 15%. The stability data showed that no significant degradation occurred under the experimental conditions. The mean recoveries at three quality control levels were within 88.7-95.7%. No significant matrix effects (105.3-109.8%) were observed in rat plasma. This method was successfully applied to the pharmacokinetic study of lupeol in rat plasma after oral administration.

Automated summary

In this study, a method for quantifying lupeol in rat plasma was developed using liquid chromatography-electrospray ionization/tandem mass spectrometry. The method showed high accuracy and precision, as well as stability under experimental conditions. It was successfully applied to the pharmacokinetic study of lupeol in rat plasma after oral administration.