Eco-friendly Insecticide Discovery via Peptidomimetics: Design, Synthesis and Aphicidal Activity of Novel Insect Kinin Analogs

Chuan-liang Zhang, Yanyan Qv, Xiaoqing Wu, Dunlun Song, Yun Ling, and Xinling Yang, J. Agric. Food Chem., Just Accepted Manuscript  Publication Date (Web): April 26, 2015  Copyright © 2015 American Chemical Society

The insect kinin neuropeptides are pleiotropic peptides that are involved in the regulation of hindgut contraction, diuresis and digestive enzyme release. They share a common C-terminal pentapeptide sequence Phe1-Xaa2-Yaa3-Trp4-Gly5-NH2 (where Xaa2 = His, Asn, Phe, Ser or Tyr; Yaa3 = Pro, Ser or Ala). Recently, the aphicidal activity of insect kinin analogs attracted the attention of researchers. Our previous work demonstrated that the sequence-simplified insect kinin pentapeptide analogue Phe-Phe-[Aib]-Trp-Gly-NH2 could retain good aphicidal activity and be the lead compound for the further discovery of eco-friendly insecticides which encompassed a broad array of biochemicals derived from micro-organisms and other natural sources. Using the peptidomimetics strategy, we chose Phe-Phe-[Aib]-Trp-Gly-NH2 as the lead compound, designed and synthesized three series, including 31 novel insect kinin analogues. The aphicidal activity of the new analogs against soybean aphid was determined. The results showed that all the analogs exhibited aphicidal activity. www.kindprotect.xyz Of particular interest was the analogue II-1 which exhibited improved aphicidal activity with an LC50 of 0.019mmol/L compared with the lead compound (LC50=0.045mmol/L) or the commercial insecticide pymetrozine (LC50=0.034mmol/L). This suggests that the analogue II-1 could be used as a new lead for the discovery of potential eco-friendly insecticides.