Features of the insecticidal action of Citrus sinensis essential oil against Musca domestica

ROSSI, Y.E.; GONZÁLEZ M.L.; CARPINELLA M. C.; ANDRIONE D.G.; PALACIOS S.M.

Citrus: Molecular Phylogeny, Antioxidant Properties and Medicinal Uses

Nova Science Publishers INC

Año: 2014; p. 169 - 183

The insecticidal action of Citrus sinensis essential oil (EO) (LC50 = 3.9 mg/dm3) against the house fly Musca domestica is reviewed with special emphasis on the process of detoxification and on the actual intoxication of the insect once it is fumigated with the EO. The first metabolic pathway of terpenes is the oxidation by P450, followed by a neurotoxic effect with characteristic features that make flies sensitive to these compounds. The same response was observed for the most abundant terpene of the C. sinensis EO, the (4R)(+)-limonene (LC50 = 6.2 mg/dm3). By comparing the activity of the EO with (4R)(+)-limonene, we propose an explanation of the enhanced activity of the first with respect to the compound. The toxicity of C. sinensis EO showed a second order response with the temperature, with a maximum at 26°C. The neurotoxic effect of C. sinensis and (4R)(+)-limonene was assayed on the enzyme acetylcholinesterase (AChE) activity and the biogenic amines levels were determined. (4R)(+)-Limonene showed a low activity against AChE, with an inhibitory percentage of 22.6% at 0.61 M (equivalent to 84 mg/mL). The levels of tyrosine, dopamine, tyramine and octopamine in M. domestica head after fumigation with the EO or (4R)(+)-limonene were analyzed by HPLC and compared with the corresponding levels of untreated flies. Fumigation with C. sinensis EO or (4R)(+)-limonene increased 8 times the levels of dopamine but they did not affect the concentration of octopamine compared with control flies. The level of tyrosine, the precursor molecule of dopamine, was enhanced 3.3 and 3.6 times when flies were submitted to both fumigants, respectively, indicating that terpenes affect the chemistry of the neurological system.