The pharmacokinetics of magnolol and honokiol in rats by LC-MS/MS

A rapid, sensitive and selective method for the simultaneous determination of magnolol and honokiol in plasma was described by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Magnolol and honokiol were separated on Waters XTerra C18 column using V(acetonitrile):V (0.1 mmol/L ammonium acetate) =75:25 as mobile phase by isocratic elution. The flow rate was 0.2 mL/min, and injection volume was 5 μL. Determination was carried out by negative ion electrospray ionization mode with selected reaction monitoring. The assay was linear from 1 to 1000 μg/L, and the lower limit of quantification (LLOQ) was 1 μg/L. The limit of quantitation (S/N=3) was 0.1 μg/L. Intra-day and inter-day precision were less than 15%. The relative deviations were in the range of 3.4%-6.6% for magnolol and 0.5%-4% for honokiol, respectively. The recoveries of magnolol and honokiol were more than 90%. The assay was applied to the pharmaco kinetic study of magnolol and honokiol after intragastric administration of Banxia-Houpu Decoction to rats.