Toxicity of Azadirachta indica Hydroethanolic Leaf Extract in Adult Drosophila melanogaster (Harwich Strain)
Okoye Clifford Tochukwu
*
Department of Plant Science and Biotechnology, University of Jos, Jos, Plateau State, Nigeria.
Etuh Monday Alexander
Africa Centre of Excellence in Phytomedicine Research and Development (ACEPRD), Jos, Nigeria and Zoology Department, Applied Entomology and Parasitology, University of Jos, Jos Plateau State, Nigeria.
Jacob Mekidani Salu
Department of Plant Science and Biotechnology, University of Jos, Jos, Plateau State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
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.
Keywords: Toxicity, Azadirachta indica, Drosophila melanogaster, hydroethanolic leaf extract