Production of (5R,6S)-6-Acetoxy-5-hexadecanolide, the Mosquito Oviposition Pheromone, from the Seed Oil of the Summer Cypress Plant, Kochia scoparia (Chenopodiaceae)

Abstract

The oviposition pheromone for the pathogen-vectoring mosquitoes in the genus Culex (Diptera: Culicidae), that is, (5R, 6S)-6-acetoxy-5-hexadecanolide, is efficiently synthesized, in admixture with the inactive (5S,6R) enantiomer ( approximately 33% w/w), from the fixed oil extracted from the seeds of the summer cypress plant, Kochia scoparia (Chenopodiaceae), cultivated on an industrial scale. Oviposition bioassays using gravid females of Culex quinquefasciatus, a vector of filariasis in human beings, showed that the product was attractive, with activity comparable to that of a pure synthetic sample containing the same amount of the active enantiomer. Production of the pheromone in the form of a biologically active crude material via a cheap and renewable plant suitable for development as a new industrial crop provides the basis for control of Cx. quinquefasciatus and other congeneric vectors of pathogens in resource-poor areas of the world.

The biology of Canadian weeds. 138. Kochia scoparia (L.) Schrad.

“…The monounsaturated fatty acid compound comprises about 5% of total kochia seed fatty acids (Whitney et al 2004). The activity and attractiveness of the pheromone were similar to that of a pure synthetic sample containing the same amount of active enantiomer (Olagbemiro et al 1999(Olagbemiro et al , 2004. Kochia foliage also contains compound(s) with insecticidal activity, and extracts from ground kochia shoot biomass were found to have acaricidal activity (contact and systemic toxicity) against three species of mites (Tetranychus spp.…”

Oviposition-deterrent, ovicidal, and repellent activities of indigenous plant extracts against Anopheles subpictus Grassi (Diptera: Culicidae)

“…Many synthetic insecticides and naturally occurring chemical cues have been shown to influence mosquito oviposition (Millar et al, 1992;Olagbemiro et al, 1999;Geetha et al, 2003). A few insecticides in common use have also exhibited high-deterrent activity, causing negative ovipositional response (Moore, 1977).…”

Arthropod semiochemicals: mosquitoes, midges and sealice

“…Terpenoid pheromones are built up via mevalonic acid through the linkage of five-carbon isoprene units in a Figure 2 Four-way choice oviposition bioassays for C. quinquefasciatus comparing the attractiveness of oviposition pheromone derived synthetically or via plant biosynthesis (using K. scoparia) [27], and the dirty water volatile skatole (a) Synthetic pheromone and skatole at 10 −10 g; (b) synthetic pheromone and skatole at 10 −9 g; (c) plant-derived pheromone and skatole at 10 −10 g; (d) plant-derived pheromone and skatole at 10 −9 g. Twenty gravid female mosquitoes were used in each assay [n = 16 for (a) and (c); n = 12 for (b) and (d)]. Significant differences from controls: *P < 0.05, **P < 0.01 and ***P < 0.001.…”

“…Apneumones from the larval-habitat-signalling plant indicator species [18] or organically enriched water sources [19][20][21] have been identified; for the mosquito C. quinquefasciatus have been used together with the C. quinquefasciatus oviposition pheromone [22,23] (compound 8 in Figure 1) to test ovitraps both in the laboratory and in the field [21,[24][25][26]. The oviposition pheromone has been produced biosynthetically, by a cheap and sustainable method, as a precursor using the summer cypress plant Kochia scoparia (Chenopodiaceae), followed by a final synthetic chemical alteration [27]. Behavioural bioassays using the volatile skatole from dirty water, together with the oviposition pheromone synthesized from K. scoparia precursors reveals identical results to the synthetic pheromone ( Figure 2).…”