title: Microsomal cytochrome P450-mediated metabolism of hypaconitine, an active and highly toxic constituent derived from Aconitum species.
abstract: Hypaconitine (HA), an active and highly toxic constituent derived from Aconitum species, is widely used to treat rheumatism. Little is known about the hepatic cytochrome P450-catalyzed metabolism of HA. The present study investigated the metabolism of HA in vitro using male human liver microsomes (MHLMS). Chemical inhibitors of specific CYP enzymes, CYP-specific inhibitory monoclonal antibodies (mAbs), and cDNA-expressed CYP enzymes were used to confirm the enzyme subtypes involved in the metabolism. Liquid chromatography-high resolution mass spectrometry (LC-MS) was used to detect and identify metabolites. A total of 11 metabolites were identified in MHLMS incubations. The major metabolic pathways included demethylation (M1-M3), demethylation-dehydrogenation (M4-M6), hydroxylation (M7, M8), and didemethylation (M9-M11). M8 was identified as mesaconitine (MA), another active and highly toxic constituent of Aconitum. The results of chemical inhibition, monoclonal antibody inhibition, and cDNA-expressed CYP enzyme studies showed that the primary contributors toward HA metabolism were CYP3A4 and 3A5, with secondary contributions by CYP2C19, 2D6, and CYP2E1. CYP1A2 and 2C8 provided minor contributions.
authors.affiliation: Department of Pharmaceutics, School of Pharmaceutical Sciences, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou, Guangdong 510515, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Ye
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.forename: Caihua
authors.initials: C
authors.lastname: Yang
authors.forename: Lan
authors.initials: L
authors.lastname: Tang
authors.forename: Juan
authors.initials: J
authors.lastname: Zhou
authors.forename: Chang
authors.initials: C
authors.lastname: Lv
authors.forename: Yun
authors.initials: Y
authors.lastname: Gong
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Jiang
authors.forename: Zhongqiu
authors.initials: Z
authors.lastname: Liu
mesh_terms: D000157:Aconitine / Q000031:analogs & derivatives* / Q000378:metabolism; D051544:Cytochrome P-450 CYP3A / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D006900:Hydroxylation; D008862:Microsomes, Liver / Q000201:enzymology / Q000378:metabolism
chemical_list: C058309:hypaconitine; C019470:mesaconitine; D003577:Cytochrome P-450 Enzyme System; C510164:CYP3A5 protein, human; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human; D000157:Aconitine