Phytochemistry and pharmacology of Harungana madagascariensis: mini review

This mini review describes the research between 1962 and 2019 on ethnobotany, chemistry and pharmacology of Harungana madagascariensis (Hypericaceae), the unique plant species in the genus Harungana. The plant is mainly distributed in Africa and Europe, where it has been used in the traditional medicine to cure several diseases. The first chemical investigation of H. madagascariensis genus took place earlier in 1962 with the isolation of harunganin whose the structure was characterized by X-ray. Several works have been done over the last 57 years on leaves, bark, roots and branches of the plant and as result, 42 secondary metabolites belonging to numerous classes of compounds including anthranoids, anthraquinones, xanthones, triterpenoids, flavonoids, steroids and alkaloids have been isolated and are presented herein together with some derivatives obtained from chemical transformations including thermal rearrangement and allylation. The anthranoids reported from natural sources represent almost 49 % of the total secondary metabolites obtained from the genus and display the most potent biological activities. Along with anthraquinones, they constitute the chemo markers of Harungana. The extracts and compounds from the plant have been evaluated for their potencies in antimicrobial, anti-protozoan, anti-sickling, anti-inflammatory, antioxidant, enzyme inhibition or cytotoxic activities. The results support the uses of H. madagascariensis in folk medicine and provide further evidence in new drugs discovery.