The inhibitory activities of two compounds from <i>Securidaca longepedunculata</i> Fresen on the acetylcholinesterase from wheat pest <i>Schizaphis graminum</i> Rondani: <i>in silico</i> analysis

Wheat is the third most widely consumed cereal in the world, after maize and rice. However, it is regularly attacked by the wheat aphid (<i>Schizaphis graminum</i>), causing considerable damage to wheat crops. The acetylcholinesterase enzyme, which plays a key role in the transmission of the synaptic cholinergic signal, has emerged as a promising target for the development of pest control strategies. Inhibition of this enzyme leads to the paralysis or even death of the aphid. The objective of this study is to identify the bioactive compounds in <i>Securidaca longepedunculata (S. longepedunculata)</i> that are capable of interacting with acetylcholinesterase from <i>Schizaphis graminum</i> and inhibiting its activity. Furthermore, a computer simulation of these compounds in interaction with the key protein was conducted. First, the secondary metabolites of <i>S. longepedunculata</i> were selected on the basis of GC-MS data available from specific reference sources. Subsequently, the compounds were subjected to virtual screening based on their docking scores in order to identify those with inhibitory properties. The compounds with the highest scores were subjected to molecular dynamics simulation over a 50 ns trajectory. Subsequently, MMGBSA free energy calculations were conducted. The results demonstrated that eight compounds exhibited inhibitory properties, four of which (echimidine, populin, salidroside, and farrerol) demonstrated superior stabilizing effects on proteins compared to the remaining compounds. In terms of free energy by MMGBSA and molecular simulation, it was observed that echimidine and populin formed robust and stable hydrogen bonds with the amino acids of the acetylcholinesterase enzyme. This study identifies and attempts to validate the potential inhibitory activities of echimidine and populin against acetylcholinesterase, with a view to developing potent insecticides and unique treatment strategies.