Phytochemical prospection of <em>Azadirachta indica</em> stem bark ethanolic extract and evaluation of its toxicity against <em>Drosophila melanogaster</em>

Abstract

Azadirachta indica is a plant of the family Meliaceae, originating in India, whose secondary metabolites are used for medicinal and insect purposes. The fruit fly-Drosophila melanogater is widely cited in the literature as a model for toxicity testing, especially since it presents rapid development and low maintenance cost. The aim of the present work was to carry out a phytochemical prospection of the ethanolic extract of A. indica stem bark (EECAi) and analyze its toxicity against D. melanogaster. The Colorimetric Method performed the chemical gait. The flies were submitted to different concentrations of the EECAi (5 mg/mL, 10 mg/mL and 20 mg/mL), being readings of 3 h, 6 h, 12 h, 24 h and 48 h, with light/dark cycles of 12 hours. Mortality rates and damage to the locomotor apparatus were analyzed by negative geotaxia test. Phytochemical prospecting of EECAi indicated the presence of tannins, flavones, flavonols, flavonones, flavononols, xanthones, chalcones, aurones and leocoantocyanidins. This extract did not present significant toxicity when compared to the control. The damage to the locomotor system was more significant at concentration of 10 mg/mL and 20 mg/mL, in the 48 h readings. The results of the mortality rate showed that the EECAi showed no significant toxicity at the concentrations and the model tested, diverging from other studies suggesting a bioinsecticity of this plant. Further studies need to test compounds isolated from this plant.