Synthesis and insecticidal activity of O-alkylated oxirane eugenol derivatives

In the last decades, the need to prevent diseases and damage caused by the attack of various pests on plants, has led to the application of high amounts of synthetic pesticides, including insecticides, which has resulted in the development of resistance to them by several harmful organisms. As an alternative, natural products with insecticide activity have been shown promise for insect control in agriculture. Essential oils (EOs) exhibit antimicrobial activities with particular potential as insecticides. Structural modifications in the constituents of EOs can further enhance their biocidal effect.

Eugenol, the major component of clove oil, presents numerous applications including in pharmaceutical, food and agricultural industries. It is an important insecticide with large efficiency on a wide variety of domestic arthropod pests.

In the present work, O-alkylated eugenol derivatives, bearing a propyl chain with hydroxyl, methyl and ethyl esters as terminals were synthesised and further converted into the corresponding oxiranes. Oxirane derivatives were then evaluated against their effect upon the viability of the insect cell line Sf9 (Spodoptera frugiperda), in comparison with the starting O-alkylates. The results pointing to their potential as bioinsecticides, with structural changes eliciting marked effects in terms of potency.