Clerodendrum inerme (L.) Gaertn. (syn. Volkameria inermis): An Integrative Review of its Traditional Uses, Phytochemistry, Pharmacological Activities, and Therapeutic Prospects

Abstract

Clerodendrum inerme (L.) Gaertn., also known as Volkameria inermis, is an evergreen coastal shrub of the family Lamiaceae that has been used for generations in the traditional medicine of Asia, Africa, and the Pacific islands. Different parts of the plant have been employed to treat fever, skin diseases, venereal and scrofulous infections, rheumatism, asthma, hepatitis, and tumors. Modern investigations have identified a rich array of secondary metabolites, including flavonoids, phenolic compounds, diterpenoids, iridoid glycosides, sterols, and saponins and have begun to explain the biological basis of these traditional uses. Reported activities include anti-inflammatory, analgesic, antipyretic, antioxidant, anticancer and anti-metastatic, neuroprotective, antimicrobial, antidiabetic, and hepatoprotective effects. Noteworthy, the plant and its constituent hispidulin have been shown to ameliorate motor tics, a spectrum of Tourette syndrome, and the leaf extract suppresses the migration, invasion, and adhesion of lung cancer cells at non-cytotoxic concentrations. The plant has also proven useful in the green synthesis of gold and silver nanoparticles with enhanced bioactivity. Although the available evidence is promising, most studies rely on crude extracts, and standardized preparations, mechanistic validation, and clinical data are still lacking. This review brings together the current knowledge on the taxonomy, botany, phytochemistry, and pharmacology of C. inerme, with particular attention to mechanistic evidence and highlights the therapeutic potential of C. inerme and outlines the research needed to translate traditional knowledge into evidence-based applications.