Azadirachta indica derived compounds as inhibitors of digestive alpha-amylase in insect pests: Potential io-pesticides in insect pest management

The study was undertaken to determine the role of Neem (Azadirachta indica) derived compounds as bio-safe pesticides, by studying the inhibition of a digestive enzyme, alpha amylase in insect pests. Three insects were selected for the study (1): Tribolium castaneum, (2): Aulacophora foveicollis and (3): Oxya chinensis. The three insects were tested for starch hydrolyzing activity in the salivary glands and gut. Two groups of compounds, Saponin and Azadirachtin were isolated from Neem plant and were used for the inhibition of amylase enzyme. Saponins and Azadirachtin were identified as enzyme inhibitors in T. castaneum while no alpha amylase enzyme inhibition was observed for O.chinensis, A.foveicollis. To determine the effect of Saponin and Azadirachtin on the expression of alpha amylase enzyme activity, T. castaneum were fed on diet mixed with Neem leaf powder, Azadirachtin and Saponins for 4 days. Proteins were then extracted and tested for total amylase activity. There was a decrease in the amylase activity. After 4 days mortality rate was 50%