Appraisal of antiretroviral herbal medicines with proven efficacy: modulation of drug-metabolizing enzymes and permeability glycoprotein activities

Human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) constitutes a source of great concern to health authorities worldwide. Herbal medicinal products are used as a significant treatment option for the highly active antiretroviral therapies, the efficacies of which are negatively impacted by the emergence of multidrug-resistant strains to the recommended treatment guidelines. This review provides an updated synopsis of available documents on herbal medicinal products with anti-HIV activities. Concurrent consumption of herbal products with conventional drugs, which is often necessitated by co-morbidity of HIV with other diseases, can potentially alter the pharmacokinetics of the co-administered orthodox drugs. Phytochemical constituents of the herbal medicinal products with antiretroviral activities were identified, and their potential to mediate pharmacokinetic changes through modulation of drug-metabolizing enzymes and P-glycoprotein was reported. Herb-drug interactions (HDIs) that can result in significant adverse effects were also discussed with documenting the information for the therapeutic utility of these clinically effective antiretroviral herbal medicinal products with potential for development into newer anti-HIV drugs.