Design, synthesis and preliminary evaluation of mosquitoicidal activity of arecoline derivatives targeting muscarinic acetylcholine receptors.

To develop novel mosquito control agents, we designed and synthesized a series of derivatives based on the natural alkaloid arecoline as a lead compound, targeting muscarinic acetylcholine receptors (mAChRs). Using computer-aided drug design and docking techniques focused on mAChRs, we designed piperidine derivatives and screened for synthetically accessible candidates. The compounds were synthesized, structurally characterized, and evaluated for activity via a Fluo-4 calcium fluorescence assay using Chinese Hamster Ovary-K1 (CHO-K1) cells expressing the muscarinic acetylcholine receptor M1. Most compounds showed potent mAChRs agonist activity, with Half Maximal Effective Concentration (EC₅₀) values below 10 μM. In subsequent insecticidal activity tests, these piperidine derivatives exhibited strong larvicidal effects against Aedes aegypti. The Median Lethal Concentration (LC₅₀) values for compounds 1a, 2a, 3a, 4a, 13a, 22a, 2b, and 9b were 58.4, 29.6, 11.4, 21.7, 42.0, 61.7, 125.9, and 81.6 mg/L, respectively. Notably, compound 13a maintained high insecticidal activity even against pyrethroid-resistant mosquitoes, indicating a mode of action different from conventional neurotoxic insecticides. These results demonstrate that mAChR-targeting derivatives derived from betel alkaloids represent a promising strategy for developing new mosquito control agents and offer a novel approach to combating insecticide resistance.