Mechanistic insight in potential dual role of sinigrin against Helicoverpa armigera.

The adverse effect of glucosinolates on diverse phytophagous insects is well documented, but its impact on insect physiology has remained enigmatic. Here we report insights into detrimental effects of plant glucosinolate molecule, sinigrin, on Helicoverpa armigera growth and development. In-silico screening of multiple glucosinolates predicted sinigrin as one of the potential inhibitor of H. armigera cathepsin B and L. Insects fed on sinigrin containing diet showed significantly reduced growth (20-30%), delayed pupation (10-15%), decreased fecundity (50-80%) and developmental abnormalities. Further, sinigrin showed 50-60% inhibition of ex-vivo cathepsin like activity which might be a reason for growth and development related abnormalities. In-vitro and mass spectrometry studies highlighted the cytotoxicity caused due to the hydrolysis of sinigrin, into toxic isothiocyanates, in presence of H. armigera whole body extract. In conclusion, insect cathepsin inhibition and isothiocyanate mediated cytotoxicity lead to the dual adverse effect of sinigrin on H. armigera.