Potential of Origanum compactum as a cercaricide in Morocco.

At 1 mg/litre, an ethyl-acetate extract of the molluscicidal plant Origanum compactum Benth. (Lamiaceae) immobilized all of the furcocercariae of Schistosoma haematobium exposed to it, within 15 min. This apparently cercaricidal activity was attributed to the presence of terpenoids and flavonoids in the extract. Encouragingly, several non-target aquatic organisms (larvae of Culex pipiens and Artemia salina and adult Gambusia affinis) and Drosophila melanogaster appeared largely unaffected by exposure to concentrations of the extract that kill S. haematobium cercariae and Bulinus truncatus.