Mode of Action for Natural Products Isolated From Essential Oils of Two Trees Is Different From Available Mosquito Adulticides

Abstract

Insecticidal properties of natural products may present alternatives to the use of synthetic molecule pesticides that are of diminishing effectiveness due to resistance. Three compounds, thymoquinone, nootkatone, and carvacrol, components of Alaska yellow cedar, Chamaecyyparis nootkatensis (D. Don) Spach, and incense cedar, Calocedrus decurrens (Torr.), essential oils, have been shown to have biological activity against a variety of mosquito and tick species. Although these components act as both repellents and insecticides, how they function in either capacity is unknown. Their use as mosquito control insecticides would be greatly increased if their mode of action is not the same as that of currently used commercial products. This study compared the lethal dosages for nootkatone, carvacrol, and thymoquinone by using colony strains of Anopheles gambiae Giles with known mutations at three different target sites. The altered target sites evaluated were the sodium channel para-locus mutation (L1014 F KDR) that confers permethrin resistance, the ACE-1 gene that confers organophosphate and carbamate resistance, and a gamma-aminobutyric acid receptor mutation of the Rdl locus conferring dieldrin resistance. Significant increases in lethal dose were not observed in any of the mosquito strains for any of the compounds tested compared with the doses required of chemicals with known modes of action at the mutated sites. Although the mode of action was not determined, this screening study indicates that none of these compounds interact at the target sites represented in the test mosquito strains. These compounds represent a different mode of action than existing chemicals currently used in mosquito control.

Chemical composition and insecticidal activity of Cymbopogon citratus essential oil from Cuba and Brazil against housefly

“…Some studies revealed satisfactory results from the use of several essential oils for insect management such as the cosmopolitan pest house fly, Musca domestica L. (PAVELA, 2008); malarian vector mosquito, Anopheles gambiae Giles (McALLISTER & ADAMS, 2010); parasitic mites of the honeybees bee Varroa destructor (ANDERSON & TRUEMAN, 2000); Acari: Varroidae (GHASEMI et al, 2011); and the maize weevil adults, Sitophilus zeamais Motschulky (FAZOLIN et al, 2007).…”

Insecticidal Activity of Thymoquinone and Related Compounds AgainstCulex quinquefasciatus(Diptera: Culicidae)

“…aegypti mosquitoes, Ixodes scapularis (Say) ticks, and Xenopsylla cheopis (Rothchild) fleas (Dolan et al 2007). Thymoquinone and carvacrol, which are the major components of this oil, are viable compounds for vector control and commercial development (McAllister and Adams 2010). The related compounds of thymoquinone that were evaluated in this study were not as effective as thymoquinone.…”

“…aegypti larvae (Johnson et al 1998). In a more recent study, thymoquinone has been shown to have biological activity against four strains of Anopheles gambiae Giles mosquitos, exhibiting a different mode of action than what is found in currently used commercial mosquito control products (McAllister and Adams 2010). …”

“…It was observed that mortality produced by thymoquinone was not immediate, suggesting some metabolism might be necessary for the toxic effect to be achieved (McAllister and Adams 2010). The purpose of this study was to compare the toxicities of thymoquinone, arbutin, thymohydroquinone, hydroquinone, and libocedrol (Fig.…”

Sustainable malaria control: transdisciplinary approaches for translational applications

“…In combination with newly identified suitable insecticide alternatives using slow-release formulations [62,63], ITWL can be used as a substitute for IRS, since it allows protective containment of the insecticide in a polymer, resulting in a longer residual efficacy. Additionally, natural insecticides including permethrin or pyrethrin and essential oils such as thymoquinone, nootkatone and carvacol [32] should be explored if their residual period of use could be increased [33]. …”