Publication:

In vivo antimalarial activity of aqueous extracts from Kenyan medicinal plants and their interactions with chloroquine

Fifteen hot water extracts prepared from 8 plants representing 7 families used traditionally in malaria treatment in Kenya were screened for their in vivo antimalarial activity against chloroquine (CQ)-tolerant rodent malaria parasite Plasmodium berghei(strain NK65), in ICR mice. When used alone,Ficus sur leaf extract had 41% suppression of parasitemia relative to untreated controls (P= 0.002). Four plants,Albizia gummifera, Caesalpinia volkensii, Ekebergia capensis and Maytenus acuminata showed mild parasitaemia suppression ranging from 9-32%. Three plants,Ajuga remota, Azadirachta indica and Clerodendrum myricoides showed no activity at all. In combination with CQ, both F.sur leaf and stem bark extracts gave a 2-week longer survival of mice relative to the CQ-alone treated controls, although the 2 groups had comparable parasitaemia to the CQ controls before treatment. However, the combinations showed no significant reduction in parasite load. A. gummifera leaf extract/CQ combination had 2.3-fold decrease in mean parasitaemia (57%) and also prolonged the survival of mice by over 2 weeks, compared to CQ controls. The results of interactions of the 2 plants' extracts with CQ indicate a potentiation effect. We conclude that both F.sur and A. gummifera warrant further investigations to determine their potential as sources of antimalarial agents.