Quantitative structure-activity relationship of terpenoid aphid antifeedants.

A series of terpenoid compounds containing a six-member-ring were synthesized from alpha- and beta-pinenes. Antifeedant activity of these terpenoid compounds were tested on the aphid, Lipaphis erysimi (Kalt.), with promising results. Stepwise regression was applied to study the quantitative structure-activity relationship of these compounds. The statistically best model showed that the relative number of O atoms, molecular volume, HOMO-LUMO energy gap, and total charge on the positively charged fragments were the most statistically significant descriptors to predict the antifeedant activity. The possible mechanism of interaction between the antifeedant and aphid chemoreceptor was discussed.