Antileishmanial potential of medicinal plants: A global systematic and meta-analytic review of in vitro studies

Abstract

Introduction: Leishmaniasis is a major global health challenge with limited treatment options and rising drug resistance. Medicinal plants, traditionally used in many regions, offer a promising source of new antileishmanial agents. This study aims to systematically review global in vitro evidence on the antileishmanial activity of medicinal plants. Methods: Data published between 2013 and 2025 were systematically retrieved from four databases: ScienceDirect, Scopus, PubMed, and Web of Science. The search used combinations of the keywords "plant extract," "Leishmania," "medicinal plants," "herbal extract," "traditional medicine," and "herbal medicine." A total of 29 studies met the inclusion criteria, encompassing 271 in vitro experiments. The difference in half-maximal inhibitory concentration (D-IC₅₀) was calculated to compare the efficacy of the tested extracts or compounds relative to the positive control, with negative values indicating stronger inhibitory activity. Results: Seventy-two different plant species were thoroughly tested against Leishmania spp. On the other hand, the heterogeneity study revealed significant variations among studies (I-square greater than 75%). Linear regression analysis demonstrated significant antileishmanial activity for several medicinal plants and their bioactive compounds. Myrtus communis L., Peganum harmala, and Ferula macrecolea showed notable effects, with D-IC₅₀ values of −20.315, −69.650, and −13.200 μg/mL, respectively (P < 0.001). Among the bioactive molecules, terpinolene (−262.570), plumericin (−241.850), and ergosterol peroxide (−240.470) exhibited the strongest inhibitory effects, all highly significant (P < 0.001). Conclusion: This review highlights promising natural compounds with antileishmanial properties that warrant further investigation in upcoming laboratory and clinical studies.