Larvicidal Activity ofAsarum heterotropoidesRoot Constituents against Insecticide-Susceptible and -ResistantCulex pipiens pallensandAedes aegyptiandOchlerotatus togoi

Abstract

We investigated the toxicity of (-)-asarinin, α-asarone, methyleugenol, pellitorine, and pentadecane identified in Asarum heterotropoides root to third instar larvae from insecticide-susceptible Culex pipiens pallens (KS-CP strain), Aedes aegypti, and Ochlerotatus togoi as well as field-collected C. p. pallens (DJ-CP colony), identified by polymerase chain reaction. Results were compared with those of two conventional mosquito larvicides: fenthion and temephos. Pellitorine (LC50, 2.08, 2.33, and 2.38 ppm) was 5.5, 10.8, and 25.6 times, 4.5, 11.6, and 24.7 times, and 6.9, 11.1, and 24.6 times more toxic than (-)-asarinin, α-asarone, and methyleugenol against susceptible C. p. pallens, A. aegypti, and O. togoi larvae, respectively. Pentadecane was least toxic. Overall, all the compounds were less toxic than either fenthion or temephos. However, these compounds did not differ in toxicity against larvae from the two Culex strains, even though the DJ-CP larvae exhibited high levels of resistance to fenthion (resistance ratio (RR), 1179), chlorpyrifos (RR, 1174), fenitrothion (RR, 428), deltamethrin (RR, 316), chlorfenapyr (RR, 225), and α-cypermethrin (RR, 94). This finding indicates that the isolated compounds and the pyrethroid, organophosphorus, and pyrrole insecticides do not share a common mode of action or elicit cross-resistance. A. heterotropoides root-derived materials, particularly (-)-asarinin and pellitorine, merit further study as potential mosquito larvicides for the control of insecticide-resistant mosquito populations in light of global efforts to reduce the level of highly toxic synthetic insecticides in the aquatic environment.

Evaluation of silver nanoparticles toxicity of Arachis hypogaea peel extracts and its larvicidal activity against malaria and dengue vectors

“…Anal papillae region and cuticle layer of treated larvae was damaged when compared with the control larvae (Fig. 7) Structural deformities of anal papillae may be intrinsically associated with the death of the treated mosquito larvae (Perumalsamy et al 2010).…”

Larvicidal activity of the essential oil of Youngia japonica aerial parts and its constituents against Aedes albopictus

“…Thus, it is suggested that α-asarone is a major contributor to the larvicidal activity of the essential oil of Y. japonica. Moreover, compared with chlorpyrifos, α-asarone was 12 times less toxic to A. albopictus larvae ( [27,28]. Menthol also possessed larvicidal activity against the fourth instar larvae of A. aegypti with a 24-h LC 50 value of 365.8 ppm [29,30].…”

Cloning and overexpression of transferrin gene from cypermethrin-resistant Culex pipiens pallens

“…Cypermethrin (Mugni et al 2011) is commonly used for the treatment of bed nets and as a residual spray to help control malaria transmission. Unfortunately, the widespread use and incorrect application of cypermethrin and other synthetic pyrethroids have accelerated the emergence of resistance in both targeted Anopheles species and off-target species such as Culex pipiens pallens (Perumalsamy et al 2010). The elucidation of the resistance mechanism becomes important to guide the use of cypermethrin and the development of its substitutes.…”