Antiplasmodial, antioxidant and toxicological study of leaves extracts of Dalbergia katangensis Lecheneaud (Fabaceae) from Eastern DR Congo

Abstract

Dalbergia katangensis is used in traditional medicine in Bukavu in management of malaria. In this study, antiplasmodial, antioxidant activities, and toxicological studies where carried out on aqueous and methanolic extracts of its leaves. The plant was selected following an ethnobotanical survey conducted in DR Congo and focusing on plants used traditionally to treat malaria. Extrac’s phytochemical secondary metabolites were determined using standard procedures and the antiplasmodial activity was evaluated using 4-day suppressive test, while antioxidant activity was evaluated by DPPH assay. In acute toxicity, twenty animals (5/group) were given orally singular 2000 mg of extract/kg body weight (BW) then observed for 14 days. In sub-acute toxicity assay, 200, 400 mg/kg BW/Day were given orally, and animals were observed for 28 days. The total phenolic (0.58-0.61 mg GAEg-1), total flavonoid (0.14-0.15 mg QEg-1) and total terpenoids contents (0.32-0.55 %w/w) were in the same rate in the two extracts as well as the antioxidant activity with IC50 value 1.55 ± 0.012 and 1.71 ± 0.014 μg/mL. At the highest oral dose,400 mg/kg body weight, all extracts produced 73–75% chemo-suppression against P. berghei ANKA and 28 survival days. No deaths were recorded during the acute toxicity assay suggesting the LD50 >2000 mg/kg and no abnormal behavior or variation in toxicity biomarkers were observed during the subacute toxicity assessment. Dalbergia katangensis leaves extracts showed a great antiplasmodial and a very good antioxidant activity. It can be used to prepare antimalarial recipe or isolate antimalarial compounds in the future.