Biocidal activities of Solvent Extracts of Azadirachta indica against Some Endemic Tropical Vector-borne Diseases

The biocidal efficacy of Chloroform (CEX), n-Hexane (HEX), Acetone (AEX) and Ethanol (EEX) extracts, of the bark and root of Azadirachta indica (Neem), were investigated against Anopheles gambiae and Bulinus globosus in a two-phased rapid and final screening test. Results of the phytochemical screening, indicated phytochemical constituents like; Flavonoids, Tannins, phenols, saponin, phytates, glycosides and triterpenes. All extracts were active (≥500ppm), during the rapid screening phase; hence final screening phase was also carried out. Results of the final screening shows that, the snail (B. globosus), were more susceptible to all solvent extracts compared to the mosquito larvae (An. gambiae). The ethanol extract of the bark against the snail (EEXbS) induced the highest mortality with LC50 value of 0.35ppm compared to the least, chloroform extract of the root against the larvae (CEXrL, LC50=46.0 ppm). The positive control induced mortality to both snails and larvae at 1ppm, while there was no mortality induced by the negative control. The results confirm solvent extracts of neem bark and root as potential biocidal agent against disease vectors.