In silicoevaluation of binding of phytochemicals from bayati (Anamirta cocculusLinn) to the glutathione-s-transferase of Asian Corn Borer (Ostrinia furnacalisGuenée)

Asian corn borer (ACB) is a destructive insect pest of corn and causes up to 80% yield reduction in the Philippines. Synthetic insecticides have been used to control ACB but they pose a risk to human health and the environment. The use of synergists increases insecticide effectiveness and decreases the frequency of insecticide application. In line with this principle, we performed in silico screening of phytochemicals from bayati against glutathione-s-transferase (GST), one of the important detoxifying enzymes of ACB. Homology modeling was done to generate an acceptable three-dimensional protein structure (OfGST). Through ensemble molecular docking, we found that three phytosterols (stigmasterol, lupeol, and gamma-sitosterol) from bayati have a higher binding affinity to OfGST than glutathione, its natural substrate. Molecular dynamics simulation revealed that lupeol and gamma-sitosterol have a greater stabilizing effect on OfGST than stigmasterol, as supported by the RMSD, radius of gyration, and SASA plots of all complexes.Communicated by Ramaswamy H. Sarma.