Simultaneous determination of harmine, harmaline and their metabolites harmol and harmalol in beagle dog plasma by UPLC-ESI-MS/MS and its application to a pharmacokinetic study.

•Harmine (HAR) and harmaline (HAL) are potential in AD, PD, and depression.•HAR and HAL were demethylated to form harmol (HOL) and harmalol (HAM).•HAR, HAL, HOL, and HAM were simultaneously determined by UPLC–ESI-MS/MS.•The low limits of quantification for HAR, HAL, HOL, and HAM were all 1.00ng/ml.•The pharmacokinetic study in beagle dogs after intravenously dose of HAR and HAL.