Clerodendrum serratum (L.) Moon. - a review on traditional uses, phytochemistry and pharmacological activities

Clerodendrum serratum (L.) Moon. (Verbenaceae) is an important medicinal plant growing in the tropical and warm temperate regions like Africa, Southern Asia; Malaysia and distributed throughout in forests of India and Sri Lanka. It is traditionally valued and reported for treating pain, inflammation, rheumatism, respiratory disorders, fever and malarial fever in India with a long history. To provide a comprehensive overview of the traditional and ethno medicinal uses, phytochemistry and biological activities of C. serratum with clinical and toxicity data and possibly make recommendations for further research.

All relevant worldwide accepted databases were searched for the terms "Clerodendrum", "Clerodendrum serratum", "Bharangi" and "Cheruthekku" along with the other literature from Indian classical texts and pharmacopoeias. There was no specific timeline set for the search. The accessible literatures available on C. serratum were collected via electronic search using Pubmed, Scopus, Science Direct and traditional books reports on ethnopharmacology and traditional medicines.

C. serratum has played an important role in Indian system of medicine. In addition to the common local use in respiratory diseases, other ethnomedicinal uses include treatment of pain, inflammation, rheumatism and fever especially malarial fever. Scientific studies on extracts and formulations revealed anti-asthmatic, mast cell stabilization and anti-allergic effects of roots of C. serratum. Reported data on pharmacological activities also includes hepatoprotective, anti-oxidant, anti-inflammatory and anticancer potential of the drug. Saponins (terpenoids and steroids), flavonoids and phenolics isolated from roots have been the focus of phytochemical investigations as the biological activity has been ascribed to the saponins, which are known to possess anti-inflammatory and anti-cancer activity. Isolated bioactives from roots like icosahydropicenic acid and ursolic acid have been claimed to offer anti-allergic and hepatoprotective activity.

Therapeutic potential of roots and leaves of C. serratum has been demonstrated in the conditions like asthma, allergy, fever, inflammation and liver disorders attributed to the presence of various flavonoids, phenolics and saponins present in the drug. Many ethnobotanical claims have been confirmed through modern in-vitro and in-vivo pharmacological studies of different extracts and isolates from plant; however, additional studies on the biomarkers are needed to establish mechanism of action and to validate the traditional use of this drug in clinical practices after proper safety assessment.