Antiplasmodial and Radical Scavenging Activities of flavonoids from Kenyan Erythrina species

Abstract

The success of quinine and artemisinin as potent natural antimalarial ,drugs demonstrates the importance of plants, especially those used in traditional medicine, as potential source of antimalarial agents. Erythrina abyssinica (Leguminosae) is one of the most widely used plants to treat malaria in East Africa. The root bark of this plant showed antiplasmodial activity against the chloroquine sensitive (06) and chloroquine resistant (W2) strains of Plasmodium JaJciparum, with ICso values of 0.64 and 0.49 ug/ml, respectively (Yenesew et al., 2003). Several compounds isolated from this plant (Kamat et al., 1981; Yenesew et aI., 2003) were also tested (Yenesew et aI., 2003; 2004). Activity was observed among pterocarpans (e.g. erythrabyssin-II, IC508.1 and 6.S ~lM against the 06 and W2 strains, respectively), and flavanones (e.g. abyssinone-1V, ICso 9.0 and 7.7 ~lM against 06 and W2 strains, respectively). However the activities of these compounds individually are much lower than that of the crude extract, indicating-that these flavonoids and isoflavonoids may be more effective as mixtures.