In vivo antiplasmodial activities of four Nigerian medicinal plants

Infusions and decoctions of Nauclea latifolia, Artocarpus altilis, Murraya koenigii and Enantia chlorantha are used ethnomedicinally as antimalarial and febrifuge in West and South Africa, especially Nigeria and Cameroon (Madubunyi, 1995; Adjanohoun et al., 1996; Betti, 2002; Ogbonna et al., 2008; Adebayo and Krettli, 2012). Therefore, aqueous-ethanolic extracts of N. latifolia root and A. altilis stem bark were investigated for prophylactic, chemosuppressive and curative antiplasmodial activities using Plasmodium berghei berghei infected mice (Peters, 1967; Ryley and Peters, 1970). The curative activity of E. chlorantha was also studied. Using the three models, the activities of all the extracts were significantly (p < 0.05) less than those of the positive controls. The standard drug chloroquine gave ED₅₀,ED₉₀ of 2.19 ± 0.10; 4.29 ± 0.1 and 2.16 ± 0.02; 4.14 ± 0.02 mg/kg for the chemosuppressive and the curative test respectively, while Pyrimethamine gave 0.45 ± 0.11 and 0.91 ± 0.11 mg/kg for the prophylactic test. The order of curative activities was E. chlorantha = N. latifolia > A. altilis. The chemosuppressive ED₅₀ 235.5 and 279.3 mg/kg and prophylactic ED₉₀ values of 455.7 and 356.0 mg/kg for A. altilis and N. latifolia, respectively differed significantly (p < 0.05). Hence, the extract of A. altilis had a higher chemosuppressive activity while N. latifolia stem and root had higher prophylactic and curative activities. Therefore, the combinations of A. altilis and N. latifolia, and A. altilis, E. chlorantha and N. latifolia, as used in herbal decoctions, were evaluated for their antiplasmodial activities in order to have a scientific justification for the ethnomedicinal antimalarial use of these plants. The results may also suggest that their combinations in an herbal potion may be beneficial in preventing, suppressing and curing malaria infection, as is currently obtained in Artemisinin Combination Therapy drugs.