Antioxidant and Antimalarial Activities of Methanol Extract of Picralima nitida Root Bark

Ethnomedically, the root, stem bark, seed or leaves of Picralima nitida are relevant in local preparations as antimalaria, antipyretic, antihypertensive and gastrointestinal agents. This study was therefore designed to determine the antimalarial and antioxidant effects of the methanol extract of the root bark of Picralima nitida using standard procedures. The antioxidant activity of the methanol root bark extract was evaluated using 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging method and ferric reducing antioxidant power (FRAP) assay. The antimalarial activity of the methanol root bark extract was investigated using the 4-day suppressive test in mice infected with Plasmodium berghei. The extract showed a concentration-dependent antioxidant activity with 50% inhibitory concentration (IC50) for free radical scavenging activity of 10.19 µg/mL, while the FRAP value was 0.17 ± 0.00 mM FSE/g Extract. The extract demonstrated significant antimalarial activity with 68.33% and 67.27% parasitaemia suppression at doses of 400 mg/kg and 800 mg/kg, respectively. The present study has shown that the root bark extract of P. nitida has antioxidant and antimalarial activities. This study does not only validate the claimed ethnomedicinal use of the plant as antimalaria but also has shown the plant as a potential source of active antimalarial agent.