In vivo chemosuppressive activities of combinations of four Nigerian ethnomedicinal antimalarial ferns

Abstract

Background to the study: The in vivo antimalarial activities and the effects of combining the methanol extracts of four ferns namely, Nephrolepis biserrata (NB), N. undulata (NU), Platycerium stemaria (PS), and P. angolense (PA) randomly and with chloroquine, was determined. Methods: The four ferns were collected, separately air-dried, powdered and the extracts was obtained by cold maceration with methanol and evaporation in vacuo. They were subsequently investigated (0-800mg/kg) for antimalarial potency against chloroquine-sensitive Plasmodium berghei berghei in mice using the Peters’ four-day test after preliminary toxicity studies, using Lorke’s method. They were further tested separately, combined with chloroquine and randomly combined with each other at their respective median effective doses. Result: NB and PS elicited comparable ED50 and lower activities than NU while PA was the least active. The percentage chemosuppression elicited by all the individual extracts were comparable [p>0.05] to that of chloroquine when combined, with chloroquine and each other, except for NU and PS. Also, NB+PA, NB+PS, NU+PA+PS, NU+NB+PS and NU+NB+PA gave comparable [p>0.05] chemosuppression to CQ. However, NU+PA, NU+CQ and PS+CQ elicited similar survival times and % survivor with chloroquine. The activities of the lower - acting PA and PS was only improved by combination with either NU or NB and did not give better effects than the most active individual drug. Conclusion: The study confirms the ethnomedicinal use of NU and NB for malaria and indicate that combining the ferns did not give any significant increase in activity better than the most active individual or the standard drug.