The influence of genetic polymorphisms and natural health products on drug metabolism

Abstract

The activities of two major components involved in drug metabolism, P-glycoprotein (P-gp) and members of the cytochrome P450 oxidase (CYP) family were studied. This investigation specifically examined the influence of polymorphisms within the ABCB1 gene on P-gp efflux activity and expression. Additionally, the role of natural health products (NHPs) on the activity of both P-gp and members of the CYP3A subfamily was also studied. Findings from this study suggest that the haplotype relationship of C3435T, G2677A/T and C1236T within the ABCB1 gene does not influence P-gp efflux activity or expression. Furthermore, some commonly consumed NHPs, including trans-beta-carotene, Arctostaphylos uva-ursi L. (Kinnikinnick), Acorus americanus Raf. and Acorus calamus L. (Acorus), Curcuma longa L. (turmeric powder), Capsicum annuum L. (chilli powder) and Piper nigrum L. (black pepper), are able to influence the activity of P-gp and members of the CYP3A subfamily in vitro. The results suggest that in order for conventional drug therapy to he effective, the genotype of an individual in relation to drug metabolism, as well as the influence of concomitantly consumed NHPs, should be considered in determining how the bioavailability of therapeutic drugs are influenced.