Toxicity of Azadirachta indica Hydroethanolic Leaf Extract in Adult Drosophila melanogaster (Harwich Strain)

Aim: This study is aimed at evaluating the toxic effect of A. indica hydroethanolic leaf extracts in D. melanogaster (fruit flies) by carrying out a survival study, locomotor, fecundity and biochemical assays.

Place of study: This study was carried out in the Drosophila laboratory of Africa Centre of Excellence in Phytomedicine Research and Development (ACEPRD), University of Jos.

Methods: Extraction of A. indica extract was carried using hydroethanolic solvent (70:30 v/v ethanol: water). Flies were treated with 5 mg, 10 mg, 20 mg, 50 mg, 100 mg, 250 mg, 500 mg and 5000 mg A. indica hydroethanolic leaf extracts per 10 g fly food for 7 days, to determine the lethal concentration (LC50). The survival assay was carried out for 28 days by treating flies with 5 mg, 10 mg, and 25 mg/10 g fly food of the extract. Young flies were treated with several concentrations of the extract for 7 days, to determine the effect of the extract on the fecundity and locomotion. Thereafter, flies exposed to the extracts for 7 days were immobilized, weighed, homogenized, and centrifuged. The supernatant was used to assay for acetylcholinesterase and catalase activities. The experiment was replicated 3 times and data was presented as mean ± SEM with statistical value at “P < 0.05” considered significant.

Results: The percentage yield was calculated to be 12.7 % and the phytochemicals present in A. indica hydroethanolic leaf extract included alkaloids, flavonoids, saponins, tannins, steroids, phenols, and glycosides. The LC50 was determined to be 1499 mg/10 g diet and the result showed a dose-dependent significant decrease (P < 0.05) in the survival of the flies, when compared to the control group. Further results showed a non-significant decrease (P > 0.05) in the fecundity, as well as the locomotor, acetylcholinesterase, and catalase activities of the flies, compared to the control.

Conclusion: This study concludes that A. indica hydroethanolic leaf extract, at certain concentrations, may not be safe for consumption as it showed some level of toxicity in D. melanogaster.