Abstract

Infections of animals with gastrointestinal nematodes constitute a world wide health problem. The aim of this study was to assess the effectiveness in vitro anthelminthic of Methylene Chloride/Methanol (1:1 volume mixture) extract of Annona senegalensis (Annonaceae) the barks of the stem on Heligmosomoides bakeri eggs and larvae (for ovicidal and larvicidal activities, respectively). Annona senegalensis is included in the list of the plants that have anthelminthic activity in the traditional medicine, just as with other plants like Albizia anthelmintica (Mimosaceae), Canthium mannii (Rubiaceae), Nauclea latifolia (Rubiaceae) and Carica papaya (Caricaceae). The plant material was collected from the peripheral savanas of Foumban, Noun Division, West Region of Cameroon. The final concentrations of plant extract tested were: 5 000, 3 750, 2 500, 1 250 and 625 μg/mL; 4 % Tween 80 aqueous solution was used as negative control. Ovicidal and larvicidal activities were assessed through egg embryonation and hatching rates and through mortality rate of L1 and L2 larvae, respectively. The extract produced low but dependant concentration on egg embryonation and hatching rates. With the highest extract concentration (5 000 μg/mL) embryonnation and hatching rates of 20.8 % and 16.1 % were obtained respectively. On the contrary, a strong larvicidal activity was observed. L1 mortality rates of 100 % and 96.7 % were recorded respectively, in the two most concentrated extract (5 000 and 3 750 μg/mL) just after six hours of exposition. L2 larvae appeared more resistant as the two most concentrated extracts (5000 and 3 750 μg/mL) produced larvicidal mortality rates of 96.1 % and 90.0 % respectively, just twenty four hours after the administration of the treatment. These results suggest that the extract of A. Senegalensis bark stem used, possess high larvicidal properties. Further more in vivo, studies assess the effects on adult worms and toxicity on mice hosts are still needed.