Potential allelopathic activity of several sesquiterpene lactone models

A collection of 12 natural and synthetic sesquiterpene lactones with eudesmanolide, melampolide, cis,cis-germacranolide, and guaianolide skeletons have been prepared and tested as allelochemicals. The effect of a series of aqueous solutions at 10−4-10−9 M ofthis collection is evaluated. The specific structural requirements related to their activity is discussed. The natural sesquiterpene lactones soulangianolide A, melampomagnolide A and B, zaluzanin C and isozaluzanin C have been synthesized from costunolide, parthenolide and dehydrocostuslactone using SeO2 and tert-butylhydroperoxide. The structures of the synthetic compounds were established by NMR spectroscopy.