In vitro and In vivo antimalarial activities of Avicennia africana P. Beauv. (Avicenniaceae) ethanolic leaf extract

BACKGROUND: The emergence of widespread drug-resistant strains of the malaria parasites militates against strives for more potent antimalarial drugs. AIM: The present study evaluated the antimalarial activity of A. africana ethanolic crude extract in vitro and in vivo against Plasmodiumberghei -infected mice in anticipation of acquiring scientific evidence for it used by mangrove dwellers to treat malaria in Ghana. METHODOLOGY: The pulverized dried leaves were extracted with 70% ethanol (v/v) and screened for phytochemicals using standard protocols. The in vitro antimalarial activity was investigated against chloroquine-sensitive Plasmodium falciparum (Pf3D7 clones), MRA-102, Lot:70032033, via SYBR® Green I fluorescent assay method using positive control Artesunate (50–1.56 × 10(−3) μg/mL). In the in vivo studies, doses (200–1500 mg/kg) of AAE were used in the 4-day suppressive and curative tests, using P. berghei-infected mice. Artemether/lumefantrine (1.14 mg/kg) and normal saline were used as positive and negative control respectively. RESULTS: The phytochemical analysis revealed the presence of alkaloids, saponins, flavonoids, glycosides, tannins, terpenoids and phytosterols. The extract showed an IC(50) of 49.30 ± 4.40 μg/mL in vitro and demonstrated complete parasite clearance at dose 1500 mg/kg in vivo 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 and the oral LD(50) > 5000 mg/kg in mice. CONCLUSION: The results demonstrated that A. africana crude extract has antimalarial activity both in vitro and in vivo supporting the traditional use of the plant to treat malaria.