title: P-glycoprotein is responsible for the poor intestinal absorption and low toxicity of oral aconitine: in vitro, in situ, in vivo and in silico studies.
abstract: Aconitine (AC) is a highly toxic alkaloid from bioactive plants of the genus Aconitum, some of which have been widely used as medicinal herbs for thousands of years. In this study, we systematically evaluated the potential role of P-glycoprotein (P-gp) in the mechanisms underlying the low and variable bioavailability of oral AC. First, the bidirectional transport of AC across Caco-2 and MDCKII-MDR1 cells was investigated. The efflux of AC across monolayers of these two cell lines was greater than its influx. Additionally, the P-gp inhibitors, verapamil and cyclosporin A, significantly decreased the efflux of AC. An in situ intestinal perfusion study in rats showed that verapamil co-perfusion caused a significant increase in the intestinal permeability of AC, from 0.22×10(-5) to 2.85×10(-5) cm/s. Then, the pharmacokinetic profile of orally administered AC with or without pre-treatment with verapamil was determined in rats. With pre-treatment of verapamil, the maximum plasma concentration (Cmax) of AC increased sharply, from 39.43 to 1490.7 ng/ml. Accordingly, a 6.7-fold increase in the area under the plasma concentration-time curve (AUC0-12h) of AC was observed when co-administered with verapamil. In silico docking analyses suggested that AC and verapamil possess similar P-gp recognition mechanisms. This work demonstrated that P-gp is involved in limiting the intestinal absorption of AC and attenuating its toxicity to humans. Our data indicate that potential P-gp-mediated drug-drug interactions should be considered carefully in the clinical application of aconite and formulations containing AC.
authors.affiliation: Key Laboratory of Drug Metabolism and Pharmacokinetics, Beijing Institute of Pharmacology and Toxicology, Beijing, China. Electronic address: yangsophia76@hotmail.com.
authors.forename: Cuiping
authors.initials: C
authors.lastname: Yang
authors.forename: Tianhong
authors.initials: T
authors.lastname: Zhang
authors.forename: Zheng
authors.initials: Z
authors.lastname: Li
authors.forename: Liang
authors.initials: L
authors.lastname: Xu
authors.forename: Fei
authors.initials: F
authors.lastname: Liu
authors.forename: Jinxiu
authors.initials: J
authors.lastname: Ruan
authors.forename: Keliang
authors.initials: K
authors.lastname: Liu
authors.forename: Zhenqing
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000157:Aconitine / Q000493:pharmacokinetics / Q000633:toxicity*; D000284:Administration, Oral; D000818:Animals; D019540:Area Under Curve; D001682:Biological Availability; D001692:Biological Transport; D018938:Caco-2 Cells; D002853:Chromatography, Liquid; D016572:Cyclosporine / Q000494:pharmacology; D004347:Drug Interactions; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects*; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000187:drug effects*; D008297:Male; D010539:Permeability; D010936:Plant Extracts / Q000493:pharmacokinetics / Q000633:toxicity; D011487:Protein Conformation; D051381:Rats; D017207:Rats, Sprague-Dawley; D053719:Tandem Mass Spectrometry; D014700:Verapamil / Q000494:pharmacology
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D010936:Plant Extracts; D016572:Cyclosporine; D014700:Verapamil; D000157:Aconitine
keywords: Aconitine; Caco-2 cells; In situ intestinal perfusion; MDCKII-MDR1 cells; Oral absorption; P-glycoprotein