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

YANINA E. ROSSI, MARÍA L. GONZÁLEZ, MARÍA C. CARPINELLA, DIEGO G. ANDRIONE AND SARA M. PALACIOS

Citrus: Molecular Phylogeny, Antioxidant Properties and Medicinal Uses.

Nova Science Publishers INC

Año: 2014; p. 1 - 199

The insecticidal action of Citrus sinensis essential oil (EO) (LC50 = 3.9 mg/dm3) against the house fly Musca domestica is revised 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 is the oxidation of terpenes by P450, followed by a neurotoxic effect with characteristic features that make flies sensitive to this compound. The same analysis is made 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´s, we propose an explanation of the enhanced activity of the EO with respect to the (4R)(+)-limonene. 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 presented a low blocking of AChE, showing an inhibition percentage of 22.6% to doses of 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 was 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 levels of the precursor molecule, tyrosine, was enhanced 3.3-3.6 times when flies were submitted to those fumigants, indicating that terpenes affect the chemistry of the neurological system.