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Veterinary Medicine International
Volume 2011 (2011), Article ID 140293, 5 pages
http://dx.doi.org/10.4061/2011/140293
Research Article

The In Vitro Effects of Aqueous and Ethanolic Extracts of the Leaves of Ageratum conyzoides (Asteraceae) on Three Life Cycle Stages of the Parasitic Nematode Heligmosomoides bakeri (Nematoda: Heligmosomatidae)

1Department of Animal Biology, Faculty of Science, University of Dschang, P.O. Box 067, Dschang, Cameroon
2Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaounde, Cameroon

Received 18 December 2010; Revised 27 March 2011; Accepted 16 May 2011

Academic Editor: David W. Horohov

Copyright © 2011 J. Wabo Poné et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A comparative in vitro study was carried out to determine the ovicidal and larvicidal activity of aqueous and ethanolic extracts of Ageratum conyzoides (Asteraceae) leaves on the eggs (unembryonated and embryonated), first and second larval stages of Heligmosomoides bakeri. Four different concentrations (0.625, 1.25, 2.5, and 3.75 mg·mL−1) of both aqueous and ethanolic extracts were tested. Distilled water and 5% tween were used as negative controls in the bioassay. In fact, they did not affect development of eggs, hatching, and larval survival. The extract activities were dose dependent. The ethanolic extract was more potent against embryonation (39.6 ± 2.9%) than the aqueous extract (53.3 ± 10.9%) at the highest concentration (3.75 mg·ml−1). Both types of extracts killed larvae. Mebendazole proved more lethal (EC50 of 0.745 and 0.323 mg·mL−1, resp., for L1 and L2 larvae). The aqueous extracts were the least lethal (EC50 of 4.76 and 2.29 mg·mL−1, resp., for L1 and L2 larvae). The ethanolic extracts showed intermediate activity (EC50 of 1.323 and 1.511 mg·mL−1, resp., for L1 and L2 larvae). It is concluded that the ovicidal and larvicidal properties of aqueous and ethanolic extracts of Ageratum conyzoides leaves are demonstrated in this work.