Estimation of chemical structure of notopterol metabolites

Notopterol, 5[(2E)-5-hydroxy-3,7-dimethyl-2,6-octadienyloxy]psoralen showed an inhibitory effect on aminopyrine N-demethylase activity in liver microsomes. In addition, notopterol has been found to be metabolized by cytochrome P450, and two kinds of metabolites were formed from notopterol. Furthermore, specific cytochrome P450 3A4 inhibitors which were isolated from grapefruit juice had the same furocoumarin structure as notopterol. Two metabolites of notopterol were separated by HPLC, and the chemical structures of the hydroxylated metabolites were estimated by 1H-NMR spectra and liquid chromatography-mass spectrometry.