A review on the genus Melodinus: traditional uses, phytochemical diversity and pharmacological activities of indole alkaloids

Abstract

Indole alkaloids are an important group of natural products in the plant kingdom for their diversity structures and significant biological effects on human health. The genus Melodinus (family Apocynaceae) is rich in mono- and bis- indole alkaloids, which have been widely studied for medicinal research. The plants of genus Melodinus are traditionally used for the treatment of hernia, abdominal pain, pediatric malnutrition, indigestion, orchitis, pediatric meningitis, fractures, and rheumatic heart diseases. This article is aimed to provide a comprehensive review on phytochemical diversity of indole alkaloids from the genus Melodinus along with their pharmacological effects. To date, a total of 345 indole alkaloids have been reported from 21 medicinal Melodinus species. These indole alkaloids contain aspidospermine-type, vincadine-type, eburnamine-type, monoterpenoid quinolone-type, bis-indole alkaloids, and so on. And the main skeleton types are aspidospermine-type and monoterpenoid quinolone-type alkaloids. Some of them exhibited cytotoxic, antimicrobial, anti-inflammatory, antifungal, and antioxidant activities. This review presents the structure skeleton, distribution, therapeutic potential and pharmacological activity of indole alkaloids from the Melodinus species, which may promote further development and utilization of Melodinus species.