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

Abstract

One new natural benzaldehyde derivative (1), together with five known compounds, was isolated from the methanolic extract of the whole plant of Cyperus rotundus 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 via 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 in vitro insecticidal efficacy of compounds 1–6 was evaluated against Nilaparvata lugens. Compound 1 demonstrated exceptional lethal and notable enzyme inhibitory effects. Furthermore, compound 1 was investigated in silico for its anti-pesticidal activities targeting the BPH (Nilaparvata lugens (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.