Nematicidal Activity of Methanolic Extracts of Leaf, Stem Bark, and Root of Azadirachta Indica (Neem) Against Haemonchus Contortus

Abstract

Livestock, especially small ruminants, represent a significant asset among resource-poor smallholder farmers, particularly the pastoralist communities. The main aim of this study is to evaluate the potency of methanolic extracts of Azadirachta indica (neem) leaves, stems, barks, and roots against Haemonchus contortus. Different parts (leaf, stem bark, and root) of A. indica (neem) were collected in Gwagwalada. The plant was identified in the Herbarium Section of the Department of Biological Sciences, University of Abuja. Abuja. The different parts of A. indica (neem) were air-dried at ambient temperature, after which each was pounded separately using a pestle and mortar and later sieved using a sieve mesh. 500g of each plant part was stored concealed at room temperature until required for use. 500g of each plant part collected was defatted in 2.5 litres of absolute methanol at room temperature for 8 hours to obtain the methanolic extract. The extract was filtered, and the filtrate evaporated to dryness at 50 °C under reduced pressure. The extracts were collected and concealed in aluminium foil paper and stored in a refrigerator at 4 °C until required. The goat’s intestinal waste was obtained from the Gwagwalada abattoir and conveyed in clean polythene bags to the Biology Laboratory, Department of Biological Science, University of Abuja. The waste content was placed on a fluorescent picking board; the parasites were picked with a picker and transferred to Petri dishes containing water. 120 larvae in 0.1 ml in wells of microtitre plate (10 larvae in each microtitre) and concentrations of each of the extracts (leaf, stem, bark, and root) at 0.1 mg/ml, 1.0mg/ml, 10.0mg/ml, 100mg/ml, negative control (water) and positive control (Levamisole) was added to each of the wells. The phytochemical screening showed the presence of carbohydrates, cardiac glycosides, saponins, flavonoids, tannins, and alkaloids and absence of anthraquinones derivatives in stem bark, root, and leaf of A. indica (neem), presence of steroids in leaf and absence in stembark and root, presence of triterpenes in both stembark and root and its absence in leaf. Mortalities recorded were high in the positive control wells, increasing mortality as the time of exposure increased. At 24 hours of parasites exposure to the positive control, there was almost complete mortality of the parasites; none of the parasites survived in the positive control wells from the 30" hour of exposure. Only one mortality was observed in the negative control wells; even in wells with the highest exposure time, mortalities were not recorded. Mortalities of the parasites increased with an increase in concentration and with the time of exposure.