Antidiabetic, Antisickling and Antibacterial Activities of Anacardium occidentale L. (Anacardiaceae) and Zanthoxylum rubescens Planch. Ex Hook (Rutaceae) from DRC

It was recently reported a rare association of two genetic diseases notably sickle cell anemia and diabetes in one patient in the Democratic Republic of the Congo. Both diseases constitute a serious public health problem and have a common denominator that is to make patients susceptible to bacterial infections. Given the difficult and limited management of these diseases, the use of medicinal plants is considered as an effective alternative. Leaves of Anacardium occidentale and Zanthoxylum rubescens collected in the surroundings of University of Kinshasa and Gbadolite in Kinshasa and Nord Ubangi provinces respectively and these plants were selected through a chemo-taxonomic approach while a phytochemical screening was performed using a qualitative approach. Bacterial strains used to assess the antibacterial activity were Staphylococcus aureus and Escherichia coli and mice were used for the antidiabetic activity. The phytochemical screening revealed the presence of tannins, anthocyanins, leucoanthocyanins, flavonoids, bound quinones as well saponins and alkaloids. The aqueous extracts of A. occidentale and Z. rubescens showed an antisickling activity. Only S. aureus was sensitive to A. occidentale where petroleum ether extract (MIC = 125 μg.mL -1 ) showed a good activity than other extracts and no activity was observed on E. coli. Meanwhile, Z. rubescens showed no antibacterial activity on both strains (MIC = > 500 μg.mL -1 ). The mean values of blood glucose after 120 minutes in untreated and treated mice were 99.5 ± 7.77mg.dL -1 (0.9% NaCl), 41.6 ± 10.07mg.dL -1 (Glibenclamide 10mg.Kg -1 ) and 64 ± 13.98mg.dL -1 (methanolic extract of A. occidentale 500mg.Kg -1 ). These findings show that A. occidentale plant possess an antihyperglycemic activity. To our knowledge, it is for the first time that the antisickling activity of A. occidentale and Z. rubescens is reported thus validating the chemotaxonomic approach used as a criterion of selection of these two plants. It is also for the first time that antidiabetic activity of A. occidentale is reported.