LARVICIDAL ACTIVITY OF THE NAPHTHYLISOQUINOLINE ALKALOID DIONCOPHYLLINE-A AGAINST THE MALARIA VECTOR ANOPHELES-STEPHENSI

The larvicidal activity of dioncophylline A, a naphthylisoquinoline al kaloid derived from the tropical vine Triphyophyllum peltatum (Dioncop hyllaceae), was investigated against the malaria vector Anopheles step hensi. In direct and indirect inhibition assays it was demonstrated th at the younger larval stages were very sensitive towards this natural product, with LC(50) values below 1 mg/l. Pronounced effects were obse rved within 4 h of exposure. Aging larvae, however, were less sensitiv e, while pupae were totally insensitive to the action of dioncophyllin e A. The transformations from larvae to pupae and from pupae to adult mosquitoes remained unaffected. Therefore, dioncophylline A can be reg arded as a promising specific larvicide.