Antihypertensive Herbal Medicines as Adjuncts to Guideline-Based Care: A Narrative Review of Clinical Evidence, Mechanisms, Safety, and Translational Challenges

Abstract

Hypertension is a leading modifiable cause of cardiovascular, cerebrovascular, and renal disease. Herbal medicines remain widely used because they are culturally familiar, perceived as safe, accessible in many communities, and biologically plausible. This narrative review synthesizes evidence on herbal products proposed for blood pressure management. The review focuses on clinical efficacy, mechanisms, safety, product quality, and translational readiness. Evidence from guidelines, randomized trials, systematic reviews, mechanistic studies, ethnobotanical reports, pharmacovigilance literature, and Indonesian regulatory sources was appraised qualitatively. A qualitative approach was used because studies differ in botanical identity, plant part, extraction method, dose, comparator, follow-up duration, blood pressure measurement, and adverse event reporting. The strongest clinically interpretable evidence is product-specific rather than plant-name-specific. Hibiscus sabdariffa (Roselle), Aged Allium sativum (Garlic) preparations, Olea europaea (olive leaf extract), and Camellia sinensis (Tea) derived products have randomized or synthesis-level signals suggesting modest blood pressure reduction whereas Apium graveolens (celery) and several ethnobotanical candidates remain preliminary or hypothesis generating. Proposed mechanisms include renin-angiotensin-aldosterone system modulation, nitric oxide-mediated vasodilation, antioxidant and anti-inflammatory activity, calcium-channel or sympathetic modulation, and mild natriuretic or diuretic effects. Herbal medicines should not replace validated lifestyle intervention, cardiovascular risk assessment, or pharmacotherapy in sustained, symptomatic, high-risk, or uncontrolled hypertension. Responsible integration requires standardized products, medication reconciliation, home or ambulatory blood pressure monitoring, adverse-event surveillance, and research designs that report botanical identity and product quality with the same precision expected for conventional medicines.