Antiplasmodial Activity of Uvaria klaineana

Abstract Crude extracts of UVARIA KLAINEANA Engler and Diels (Annonaceae) stems showed IN VITRO activity against chloroquine-resistant K1 strain of PLASMODIUM FALCIPARUM. The most active extract was the basic dichloromethane extract containing crude alkaloids (IC 50 = 3.55 μg/mL). The bioassay-guided fractionation of this extract led to the isolation of the major alkaloid crotsparine (1) which showed an antiplasmodial activity against the chloroquine-sensitive Thai strain of P. FALCIPARUM and the chloroquine-resistant K1 and FcB1 strains of P. FALCIPARUM. Two minor alkaloids were also identified as crotonosine (2) and zenkerine (3). Their structures were elucidated using 2D-NMR techniques.