Absorption characteristics of the total alkaloids from Mahonia bealei in an in situ single-pass intestinal perfusion assay

AIM:To investigate the absorption characteristics of the total alkaloids from Mahoniae Caulis(TAMC) through the administration of monterpene absorption enhancers or protein inhibitors.METHOD:The absorption behavior was investigated in an in situ single-pass intestinal perfusion(SPIP) assay in rats.RESULTS:The intestinal absorption of TAMC was much more than that of a single compound or a mixture of compounds(jatrorrhizine,palmatine,and berberine).Promotion of absorption by the bicyclic monoterpenoids(borneol or camphor) was higher than by the monocyclic monoterpenes(menthol or menthone),and promotion by compounds with a hydroxyl group(borneol or menthol) was higher than those with a carbonyl group(camphor or menthone).The apparent permeability coefficient(Papp) of TAMC was increased to 1.8-fold by verapamil,while it was reduced to one half by thiamine.The absorption rate constant(Ka) and Papp of TAMC were unchanged by probenecid and pantoprazole.CONCLUSION:The intestinal absorption characteristics of TAMC might be passive transport,and the intestinum tenue was the best absorptive site.In addition,TAMC might be likely a substrate of P-glycoprotein(P-gp) and organic cation transporters(OCT),rather than multidrug resistance protein(MRP) and breast cancer resistance protein(BCRP).Compared with a single compound and a mixture of compounds,TAMC was able to be absorbed in the blood circulation effectively.