Bioactive N-isobutylamides from the flower buds of Spilanthes acmella.

The hexane extract of dried flower buds of Spilanthes acmella afforded three N-isobutyl amides: spilanthol, undeca-2E,7Z,9E-trienoic acid isobutylamide and undeca-2E-en-8,10-diynoic acid isobutylamide. Their structures were determined by 1H and 13C NMR, MS and GC-MS spectroscopic methods. All were active against Aedes aegyptii larvae and Helicoverpa zea neonates at 12.5 and 250 micrograms/mL concentrations, respectively.