Ethnopharmacology versus biological activity : a review with emphasis on the triterpene class

Abstract

Ethnopharmacological relevance: In recent years, several studies aim to validate the traditional medicinal use of a variety of plant species, through evaluation of extract activity and/or isolation of active constituents. We discuss herein the latest studies on the ethnopharmacology of species with active secondary metabolites from the triterpene class. Aim of the review: This review aimed to verify, through bibliographic research, the correlation between traditional medicinal use and biological activity of natural sources, with emphasis on the triterpene class of active secondary metabolites. Methods: Literature research was done in ScienceDirect® database, using the keywords ethnopharmacology and triterpenes, from the period of 2015 and 2016. From 182 studies evaluated, 32 studies were selected. The selected studies were the ones relating the activity of a triterpene, isolated from a natural source extract, to its traditional medicinal use, or the studies relating the traditional medicinal use of a natural source and the activity of its extract, which may be due to the presence of a triterpene. Results: Twenty studies on the in vitro / in vivo activity of isolated triterpenes are reported here, and 12 studies where the activity of the extract might be related to the presence of triterpenes. The most cited activities for the class include antitumoral, anti-mycobacterial, antiplasmodial, antibacterial and anti-inflammatory. The medicinal parts mostly used for extraction were the leaves. The most cited triterpene was betulinic acid, presenting anxiolytic activity in vivo and antimycobacterial, antitumoral, and antiplasmodial activities in vitro. Conclusion: The relationship between traditional medicinal use and biological activity was demonstrated for a wide variety of natural source extracts as well as isolated compounds. Nevertheless, future studies are necessary focusing on understanding the pharmacological basis of the traditional use of some natural sources, as well as on generating conclusive data on their efficacy and safety, in order to validate their use in traditional medicine.