<i>In Vivo</i> Antiplasmodial Activity of Different Solvent Extracts of <i>Myrianthus libericus</i> Stem Bark and Its Constituents in <i>Plasmodium berghei</i>‐Infected Mice

Abstract

The emergence and resurgence of <i>P. falciparum</i> resistance to generations of antimalarial drugs have prompted the search for new, effective, and safe antimalarial agents. This study aimed at investigating the <i>in vivo</i> antiplasmodial activity of the 70% hydroethanolic extract and constituents of the stem bark of <i>Myrianthus libericus</i> based on its ethnomedicinal use as an antimalarial agent. The antiplasmodial activity was assessed in Swiss albino mice employing the 4-day suppressive and Rane's tests. MLB significantly (<i>p</i> < 0.0001) suppressed parasitaemia by 52.26%, 65.40%, and 77.11% at 50, 100, and 200 mg·kg^-1 doses, respectively, in the 4-day suppressive test. In Rane's test, the highest parasitaemia suppression of 72.50% was recorded at a dose of 200 mg·kg^-1 of the extract. Fractionation of the bioactive ethyl acetate fraction by solvent-solvent partitioning and column chromatography led to the isolation of friedelan-3-one and stigmasterol being reported for the first time from this species. The compounds demonstrated remarkable antiplasmodial activity by suppressing parasitaemia by 65-72% in the suppressive test and 61-70% in the curative test at doses of 10-30 mg·kg^-1. Both the extract and the isolated compounds significantly prolonged the survival time of infected mice and averted the cardinal signs associated with <i>P. berghei</i>-induced malaria including weight loss, hypothermia, and haemolysis. The results obtained confirm the prospect of <i>M. libericus</i> as an important source of new antimalarial compounds and justifies its folkloric use as an antimalarial agent.