Phytochemical and pharmacological studies of clusiaceae (Garcinia brevipedicellata Oliv.)

Abstract

Within the framework of building a scientific data base of Cameroonian medicinal plants, phytochemical investigations have been carried out on a plant currently used by traditional healers to solve daily health problems of the population. The main aim of this work is to complete the results already obtained from biological and biochemical tests carried out on the extracts of 100 selected plants currently used in folk medicine. The specific objective is to elaborate a good extraction protocol of the leaves of Garcinia brevipedicellata (Clusiaceae), and then followed by the purification of the extracts so as to know and compare the different classes of secondary metabolites found in this extract. It is also important to carry out other related tests to identify the biological activities of these constituents. From the ethyl acetate extract of the leaves of Gacinia brevipedicellata, seventeen compounds were isolated which were given the abbreviations GBr-1-GBr-17 and the first nine (GBr-1-GBr-9) were characterized using routine spectroscopic methods including 1D and 2D NMR as well as by comparing obtained data with literature. Among these, two ether biflavnoids trivialy named brevipedicelone D and brevipedicelone E were new. The other compounds were identified as robustaflavone, 4-O-Me-robustaflavone, brevipedifloside A, apigenine, 2ˈ-hydroxy -4ˈ- O-methylgenistein, amentoflavone and luteoline respectively. The two new compounds were evaluated for anti-onchocercal activities. It was found that among the two compounds tested only brevipedicelone D showed moderate inhibition of the adult worm motility of Onchocerca ochengi by 60 % at the highest concentration (20 μg/ml) and inhibited motility of both the juvenile worms of O. ochengi and Loa loa 90 % at this same concentration.