ASSESSMENT OF ANTIMALARIAL ACTIVITY AND TOXICITY OF AVICENNIA AFRICANA ETHANOL LEAF EXTRACT IN RODENT MODEL

ABSTRACT

The emergence of widespread drug-resistance strains of the malaria parasites militates against strives for more potent antimalarial drugs. Therefore, a renewed effort to search for new drugs from medicinal plants focusing on the mangroves in Ghana has become imperative. Hence, this study aimed at evaluating the in vitro and in vivo antimalarial activity and toxic effect of the crude extract of Avicennia africana leaf in rats. The pulverized dried leaves were extracted with 70% ethanol to obtain the crude extract (AAE). Phytochemical screening was done using standard protocols. Dose levels ranging from 100 to 5000 mg/kg were used in the acute and sub-acute toxicity studies and histopathological analysis. An antimalarial activity study was done (in vitro) on the extract against chloroquine-sensitive 3D7 P. falciparum clones, using the SYBR® Green I fluorescent assay method. In the in vivo studies, dose levels (200-1500 mg/kg) of AAE were used in the 4-day suppressive and Rane’s test, using P. berghei-infected mice. The phytochemical analysis revealed the presence of alkaloids, saponins, flavonoids, glycosides, tannins, terpenoids and phytosterols. The toxicity test showed that the extract was safe up to 5000 mg/kg and has no damaging effects on blood parameters and the internal organs. In the in vitro study, the extract showed an average IC50 value of 49.30±4.40 μg/mL. The extract at dose 1500 mg/kg showed a mean parasitaemia of 0.00±0.00 with a suppressive activity of 100% (p < 0.0001) in the 4-day suppressive test. The extract demonstrated high curative activity (p < 0.0001) at 1500 mg/kg with 100% parasite inhibition. In conclusion, A. africana crude extract has a potential antimalarial activity both in vitro and in vivo and may be considered as a prospective source to advance a new antimalarial drug.