A new natural Cyperol A together with five known compounds from <i>Cyperus rotundus</i> L.: isolation, structure elucidation, DFT analysis, insecticidal and enzyme-inhibition activities and <i>in silico</i> study

One new natural benzaldehyde derivative (1), together with five known compounds, was isolated from the methanolic extract of the whole plant of <i>Cyperus rotundus</i> L., which is a globally distributed noxious weed. The structure of compound (1) (named Cyperol A) was determined using various NMR methods, including ¹H, ¹³C, COSY, HMBC, HSQC and NOESY, and mass spectrometric techniques, including EIMS. The newly isolated compound (1) was subjected to optimization using computer-assisted calculation <i>via</i> DFT methods for natural bond orbital (NBO) and frontier molecular orbital (FMO) analyses and compared with carbofuran, which is used to control the pest brown planthopper. The <i>in vitro</i> insecticidal efficacy of compounds 1-6 was evaluated against <i>Nilaparvata lugens</i>. Compound 1 demonstrated exceptional lethal and notable enzyme inhibitory effects. Furthermore, compound 1 was investigated <i>in silico</i> for its anti-pesticidal activities targeting the BPH (<i>Nilaparvata lugens</i> (Stål)) key enzymes, such as glutathione S-transferase (GST) and acetylcholinesterase (AChE). Compound 1 showed good docking scores of -9.75 kcal mol^-1 against GST, forming hydrogen bonds with its active site, and -10.56 kcal mol^-1 with AChE owing to its high potential for hydrogen bonding.