Cyclic and acyclic alcohols: a structure-activity relationship study correlation between insecticidal activity and chemical structure

The efficiency of essential oil depends upon the chemical nature, composition, and the relative proportion of its functional groups. In some case, individual compounds can exhibit a pertinent effect than do the essential oils. To underline their efficiency according to their chemical structure, five cyclic and acyclic alcohols were tested in vitro for their potential insecticidal and repellent activities against Tribolium castaneum (Herbst). The ability to repel more than 95% was observed in all tested compounds from 15 min to 10 h, except for eugenol that exhibited the weakest effect. Fumigant bioassay showed that the five alcohols applied separately caused significant insect mortality that exceeds 60% at 400 μL/L air. The lowest median lethal dose, LC50 = 18.24 μL/L was observed with citronellol. PCA analysis revealed that the acyclic alcohols showed stronger toxicity compared to the cyclic ones. Moreover, the combined effect of these alcohols was lower than individual ones in all tested combinations. According to the outcome of this study, acyclic alcohols might be more effective in reducing stored grain Tribolium infestation than cyclic ones as a single compound. The knowledge of the degree of efficiency of each chemical group gives the possibility to create artificial combinations of different constituents for the development of more effective eco-friendly control agents.