Isolation of Natural Veratrylidenehydrazide Compound from Wedelia Biflora and Synthesis of Veratrylidenehydrazide Analogue: Investigation of Larvicidal Activity Against Culex Quinquefasciatus and Toxicity Analysis in Nontarget Aquatic Species

Abstract

AbstractIn this study, veratrylidenehydrazide was isolated from Wedelia biflora, and compounds (1a, 2a, and 3a–j) were synthesised to evaluate their larvicidal and antifeedant activities. Veratrylidenehydrazide 1a was verified using GC‐MS. The veratrylidenehydrazide analogues 2a and 3a–j were synthesised via a condensation method with yield range 71%–92%. The compounds (1a, 2a, and 3a–j) were synthesised and characterised through FT–IR, 1H NMR, 13C NMR, mass spectrometry, and elemental analysis. Veratrylidenehydrazide 1a was verified using GC‐MS analysis. Natural veratrylidenehydrazide compound 1a and the synthesised veratrylidenehydrazide analogues (2a, 3a–j) were screened for larvicidal activity against Culex quinquefasciatus. The larvicidal activity of compound 3g was found to be highly active, while low toxicity was observed against Oreochromis mossambicus nontarget aquatic species compared to natural veratrylidenehydrazide. Compound 3g exhibited a higher binding affinity (−8.8 kcal/mol) compared to standard of temephos (−4.5 kcal/mol), equipotential binding affinity against permethrin (−9.1 kcal/mol), and diflubenzuron (−8.5 kcal/mol). Lead molecules have larvicidal properties, and their use as insecticides makes them important.