Anthelmintic screening of Zimbabwean plants traditionally used against schistosomiasis

Extracts of 23 plant species used popularly against schistosomiasis in Zimb abwe were screened for their anthelmintic effect. Schistosomules of the tre matode Schistosoma mansoni and cysticercoids of the cestode Hymenolepis dim inuta were studied in vitro. The material consisted of 58 plant extracts, o f which 37 killed the newly excysted cysticercoids within an hour, when inc ubated in a culture medium. Lethal concentrations varied from 0.8 to 103 mg /ml. All plant extracts showed activity against the tapeworms after 24 h. T en of the best extracts were also tested against schistosomules. Five of th ese extracts showed activity. Lethal concentrations varied from 0.6 to 33.8 mg/ml of dry plant material. Extracts of stem and root from Abrus precator ius (Fabaceae), of root bark and leaves from Ozoroa insignis (Anacardiaceae ) and of root bark from Zizyphus mucronata (Rhamnaceae) gave the best resul ts against tapeworms. The best results against schistosomules were obtained with stem and root extracts from Abrus precatorius (Fabaceae) and stem bar k from Elephantorrhiza goetzei (Mimosaceae). Although the activity of root and root bark extracts commonly used in traditional medicine was verified i n this study, our results showed that also extracts from leaf and stem can be effective anthelmintics. (C) 2001 Elsevier Science Ireland Ltd. All righ ts reserved.