IN-VITRO AND IN-VIVO ANTIMALARIAL ACTIVITY OF CRYPTOLEPINE, A PLANT-DERIVED INDOLOQUINOLINE

Cryptolepine is an indoloquinoline, high yields of which may be extracted from the roots of the West African shrub Cryptolepis sanguinolenta. The use of this plant as a traditional treatment for malaria is widespread in Ghana and is reported to be clinically effective. We have tested cryptolepine for in vitro antiplasmodial activity against the multidrug resistant (K1) strain of Plasmodium falciparum and found it to be highly active with an IC50 value of 0.031+/-0.0085 (SE) mu g/mL, equivalent to 0.134+/-0.037 mu M (n=3). In a 4-day suppression test there was, however, no significant reduction in parasitaemia in P. berghei-infected mice treated subcutaneously with cryptolepine (7-113 mg/kg/d X 4), when compared with untreated controls. Like 9-aminoacridine, this compound appears to intercalate with DNA and this may explain the high degree of antimalarial activity demonstrated in vitro.