Novel Onchocerca volvulus filaricides from Carapa procera, Polyalthia suaveolens and Pachypodanthium staudtii.

Suitable drugs for the elimination of adult Onchocerca volvulus are still needed since ivermectin, the new microfilaricide, appears to be ineffective against this parasite stage. Herein we report on the identification of filaricides in three medicinal plants. The compounds carapolide A, mexicanolide-methylangolensate mixture from Carapa procera and oliverine from Polyalthia suaveolens or Pachypodanthium staudtii when tested at 10-100 micrograms.ml-1 were found to exhibit considerable microfilaricidal activity after 24 hours of incubation. Oliverine was found to be filaricidal when tested against adult female worms at 100 micrograms.ml-1. Preliminary toxicity studies in mice showed carapolide A and the mexicanolide-methylangolensate mixture to be relatively non-toxic, whereas, oliverine had a minimal lethal dose of 8 mg.Kg-1 of body weight. Based on the above results further pharmacologic studies are recommended to determine, the potential application of the active compounds on the treatment of onchocerciasis.