Assessment of Impacts of Clinically Effective Antihypertensive Herbal Medicines on the Activities of Major Drug Metabolizing Enzymes and Transport Proteins

Introduction: Hypertension is one of the most common non-communicable diseases, and reports indicate that its prevalence is escalating globally due to several factors. Studies in different countries have shown an upsurge in the use of Herbal Medicinal Products (HMPs), including herbal antihypertensive medicines taken by people with hypertension, and 20-80 % of hypertensive patients concurrently use these herbal medicines and conventional antihypertensive medicines or other drugs. The safety and efficacy of the concurrent use of herbal and orthodox medicines are of great concern because of the high possibility of herb-drug interactions. Methods: An extensive literature search was undertaken, and the information obtained was subjected to critical analysis. This review aimed to update the available data on HMPs with reproducible evidence-based antihypertensive efficacies. Additionally, the major phytochemical and bioactive constituents of these HMPs were identified along with a discussion of their potential to modulate activities of drug-metabolizing enzymes and drug transport systems, especially Pglycoprotein. Results: More than 50 commonly used medicinal plants from different regions of the world have been documented for their anti-hypertensive activity. Most of these studies used animal models to authenticate the antihypertensive activities of the herbs. In contrast, a few studies on extracts of Hibiscus sabdariffa, Allium sativum, Apium graveolens, Nigella sativa, Linum usitatissimum, and Camellia sinensis involved clinical trials. Potentials for herb-drug interactions varied among the clinically effective HMPs due to the wide variability in their phytochemical constituents. Conclusion: Safety issues in using these HMPs were highlighted by the identification of beneficial or adverse, clinically significant herb-drug interactions.