Screening of fruit pulp extracts of Picralima nitida against in vitro cultures of Plasmodium falciparum and acute oral toxicity in white albino mice

Abstract

The increasing resistance of Plasmodium falciparum to available  antimalarial drugs currently justifies the quest for potential antiplasmodial  agents from plants. Picralima nitida is used as a traditional remedy against malaria in Nigeria. In this study, phytochemical constituents of methanolic and aqueous extracts of P. nitida fruit pulp were screened, and tested in vitro against 20 clinical isolates of P. falciparum using the schizont growth inhibition assay. Acute oral toxicity of each extract was also evaluated in white albino mice. The results showed the presence of alkaloids,  anthraquinones, flavonoids, saponins, and tannins in both extracts. Terpenes were only present in the methanolic extract. In vitro growth inhibition of P. falciparum by each extract was dose dependent. The methanolic extract exhibited moderate, but higher antimalarial activity with IC₅₀ = 23.33 ± 0.76 µg/ml, compared to the aqueous extract with IC₅₀ = 28.25 ± 0.95 µg/ml. The difference was significant (t = 16.72, df = 19, P < 0.001). The LD₅₀ of each extract was 3807 mg/kg body weight. The moderate antiplasmodial, and toxicity of these extracts, may justify the use of P. nitida, fruit pulp for the treatment of malaria in Nigeria.

Keywords: phytochemical constituents, malaria, inhibitory concentration, lethal dose.