Biting deterrency of undecanoic acid and dodecanoic acid ester analogs against Aedes aegypti

Background: Mosquitoes remain one of the most significant threats to the health of humans throughout the world. This study was designed to evaluate the biting deterrent effects of a series of ester analogs of undecanoic acid (C:11:0) and dodecanoic acid (C:12:0) against Aedes aegypti (L), (Diptera: Culicidae), the yellow fever mosquito, using Klun and Debboun (K&D) and Ali and Khan (A&K) bioassay systems.

Results: In the K&D bioassays, C:11:0 esters methyl undecanoate, propyl undecanoate, butyl undecanoate, and pentyl undecanoate, and the C:12:0 esters methyl dodecanoate, ethyl dodecanoate, propyl dodecanoate, octyl dodecanoate, and dodecyl dodecanoate were most active. All of these esters were as effective as N,N-diethyl-m-toluamide (DEET) and as effective as the parent acids undecanoic acid and dodecanoic acid with biting deterrence index values ranging from 0.80 to 0.99. In the in vitro A&K bioassay undecanoic acid with a minimum effective dose (MED) of 3.125 μg cm^-2 was the most active compound and showed higher activity than DEET (MED of 25 μg cm^-2 ). The most active synthetic analog was butyl undecanoate with a MED of 12.5 μg cm^-2 . The next most active analogs are the methyl ester analogs methyl undecanoate and methyl dodecanoate, both with MED values of 25 μg cm^-2 .

Conclusion: Fatty acid synthetic esters and structural analogs are a promising source of new mosquito repelling compounds and should be investigated further. Published 2020. This article is a U.S. Government work and is in the public domain in the USA.

A&K bioassay; Aedes aegypti; K&D bioassay; biting deterrence; fatty acid; mosquitoes; natural products; repellency.