Effects of NeemAzal on marker enzymes and hemocyte phagocytic activity of larvae and pupae of the vector mosquito Aedes aegypti

- NeemAzal exhibited potent larvicidal and pupicidal effect on Aedes aegypti.
- NeemAzal exposure differentially affected marker enzymes of the larvae and pupae.
- Upon exposure, this neem formulation reduced hemocyte viability in vitro.
- Reduction in phagocytic activity of hemocytes was also recorded.

Many of the neem based botanical biocides are currently studied to a greater extent because of the possibility of their use in eco-friendly control of pests and vectors. However, no report was available to assess the impact of neem based formulation, NeemAzal on marker enzymes and hemocyte mediated cellular immune responses of important vector mosquito A. aegypti. The NeemAzal found to exert larvicidal and pupicidal activities against A. aegypti developmental stages. The pupae appear to be more susceptible to the treatment. Further, a significant increase in the level of total protein (31%), α-carboxylesterase (121%), β-carboxylesterase (46%), acid phosphatase (62%) and alkaline phosphatase (37%) was observed in larvae upon exposure to NeemAzal. Moreover, treated pupae showed increased level of acetylcholinesterase (116%) and acid phosphatase (43%) while α-carboxylesterase (34%), β-carboxylesterase (12%) levels were simultaneously decreased, and no significant changes in alkaline phosphatase were noticed. Qualitative analysis also revealed that the exposure considerably modulated the larval β-carboxylesterase isoenzyme profile whereas little changes were noticed on phosphatases. On the other hand hemocyte viability of larvae (18%) and pupae (16%) as well as phagocytic ability of larval (48%) and pupal hemocytes (44%) against yeast target was significantly reduced upon NeemAzal exposure. We demonstrated for the first time that the NeemAzal differentially affected the marker enzymes and created immuno-suppressive state by reducing the phagocytic ability of hemocytes of larvae and pupae of A. aegypti.