Phytochemical screening and ovicidal potential of neem (Azadirachta indica) leaf extracts using various solvents against Aedes aegypti L.

Abstract

Dengue, caused by Aedes aegypti, continues to pose significant global public health challenges. Current vector control strategies include the extensive use of chemical insecticides, which have contributed to the development of insecticide resistance and potential harm to non-target organisms, including humans. Neem (Azadirachta indica) is renowned for its insecticidal activity against mosquitoes, exhibiting ovicidal, larvicidal, pupicidal and adulticidal properties. This study evaluated the phytochemical composition and ovicidal activity of neem leaf extracts against Ae. aegypti eggs. Neem leaves were extracted using ethanol, acetone, ethyl acetate and chloroform via the maceration method for 72 hours. Each extract was analysed through phytochemical analysis tests and ovicidal bioassay. Phytochemical screening tests revealed the presence of bioactive compounds such as alkaloids, saponins, tannins, steroids, glycosides, terpenoids, and flavonoids. Statistical analysis (ANOVA) revealed a significant difference (p < 0.05) in ovicidal activity across solvent extracts. The ethanolic neem leaf extract demonstrates ovicidal activity against Ae. aegypti with 79% egg mortality at 1000 mg/L. Probit analysis further showed that the ethanol extract had the lowest LC50 (289.47 mg/L) and LC90 (2083.29 mg/L) among other solvent extracts. These findings highlight the potential of ethanolic neem leaf extract as a natural ovicide and support its use as an alternative to synthetic insecticides. Its application could be especially valuable in small aquatic habitats or breeding sites near human dwellings.