Metabolism of Magnolol from Magnoliae Cortex. I. Application of Liquid Chromatography-Mass Spectrometry to the Analysis of Metabolites of Magnolol in Rats

Abstract

As a part of our studies on the metabolism of active components from traditional Chinese medicines, magnolol was orally administered to rats. The urinary and fecal metabolites were analyzed by high-performance liquid chromatography and liquid chromatography-mass spectrometry, and their structures were determined to be tetrahydromagnolol (M1), 5-(1-propen-1 (E)-yl)-5'-propyl-2, 2'-dihydroxybiphenyl (M2), 5-allyl-5'-propyl-2, 2'-dihydroxybiphenyl (M3), isomagnolol (5, 5'-di (1-propen-1 (E)-yl)-2, 2'-dihydroxybiphenyl) (M4), 5-allyl-5'-(1-propen-1 (E)-yl)-2, 2'-dihydroxybiphenyl (M5). On the other hand, magnolol was transformed to M4 and M5 together with small amounts of M2 and M3 by anaerobic incubation with rat feces. This suggests that the isomerization of magnolol in the rat could be carried out by the action of intestinal bacteria.