Antiplasmodial activity of total alkaloids and flavonoids of stem bark extracts of Enantia chlorantha in mice

Plant-derived compounds have played vital roles in the management of malaria infections. Thus, Enantia chlorantha (Anonaceae) is one of such plants used in folklore medicine in Nigeria for the treatment of malaria. There is, therefore, a need to validate the potential in this plant by investigating its in vivo antiplasmodial activity against Plasmodium berghei-infected mice. The alkaloid and flavonoid extracts were extracted from the crude extract following standard procedure. The crude extract was orally administered to Plasmodium berghei-infected mice at 200, 400 and 800 mg/kg bodyweight (kgbw), while flavonoid fraction and alkaloid extract were each administered at a dose of 100, 200 and 400 mg/kgbw respectively for 4 days after establishment of infection. The bodyweights and packed cell volume were determined at pre- and post-treatment of infected animals, while parasitaemia was monitored daily throughout the period of treatment. Results showed that parasitaemia count was lowered in mice administered with crude and alkaloid extracts in a dose-dependent manner while the effect of the flavonoid fraction was not significant compared with infected, untreated mice (p > 0.05). The percentage parasite inhibition of the crude and alkaloid extracts ranged between 59–73% and 56–70% respectively, while that of the flavonoid fraction was in the range of 28–39%. The animals treated with crude and alkaloid extracts did not suffer much bodyweight loss. However, only the group treated with alkaloid extract at 400 mg/kgbw recorded an increase in PCV which was comparable with the chloroquine-treated group. The crude and alkaloid extracts prolonged the mean survival time of the treated mice compared with the untreated group. Overall, the findings from this study indicate that alkaloid extract of the stem bark of Enantia chlorantha may be a good source of antimalarial. In addition, the study also suggested that alkaloids and flavonoids may have synegistically ameliorated the reduction in PCV associated with Plasmodium infection.