Pseudoguaianolide sesquiterpene lactones with high activities against the human malaria parasite Plasmodium falciparum.

Four sesquiterpene lactones of the pseudo-guaianolide type (helenalin, dihydrohelenalin and their acetates), have shown activities against asexual blood forms of Plasmodium falciparum in vitro. Their IC(50) values were situated in the range of 0.23 to 7.41 micro M. The activity found for helenalin was high, even compared to the activity found for artemisinin.