Absorption and metabolism of Eucalyptus cinerea essential oil by Musca domestica L.

ROSSI YANINA E, PALACIOS SARA M

Huerta Grande

Encuentro; 2nd Latin American Meeting of Chemical Ecology; 2012

Absorption and metabolism of Eucalyptus cinerea essential oil by Musca domestica L. Yanina Estefanía Rossi, Sara María Palacios Laboratorio de Química Fina y Productos Naturales, Facultad de Ciencias Químicas, Universidad Católica de Córdoba, Argentina. yanirro@hotmail.com The house fly, Musca domestica (L.), is one of the most common insects, associated with vectoring of etiological agents of bacterial, protozoan and viral infections converting this insect in a threat to public health. Intense applications of a variety of synthetic insecticides to control M. domestica have led to the development of resistance to most of them around the world. Natural insecticides are a great alternative to conventional ones because are safe to the environment and to human being. Essential oils (EOs) are part of this new proposed as fumigants because of their high volatility, low toxicity to warm-blooded mammals and toxicity to M. domestica1. After a fumigation bioassay was performed (n=100), dead flies were collected in a vial (10 ml volume) with a septum, and then washed with hexane. The vial was placed in a bath at 60 °C for 10 min. With the aim of quantify (GC-FID) the compounds absorbed by the fly, 20 µL of a solution containing 5 mg/mL of camphor (internal standard) in acetone was added to the vial. Terpenes desorbed from M. domestica were captured using a SPME microfiber in the headspace of the vial. The assay detected two new compounds 2,3-dehydro-1,8-cineole and terpineol (Fig. 1), this result demonstrated that, in M. domestica, 1,8-cineole was transformed to these metabolites probably by the oxidative detoxification pathway P450 To assay E. cinerea EO, 1,8-cineole in combination with an inhibitor of P450 (PBO), insects were anesthetized with a CO2 current, and then a solution of PBO in acetone (20 mg/ml) was applied topically to the thoracic notum at a dose of 10 μg (0.5 μl) per fly, 1 h before the insecticide treatment. E. cinerea EO (LC50 de 5.5 a 2.2 mg/dm3) and 1,8-cineole (LC50 de 3.3 a 1.6 mg/dm3 ) showed more toxicity by action of this inhibitor of P450. In other words, the insect detoxification system contributed to decrease the toxicity of the E. cinerea EO, the metabolites presented less toxicity than 1,8-cineole (LC50 de terpineol: 36.8 mg/dm3)2. (1) Rossi, Y. E.; Canavoso, L.; Palacios, S. M. Molecular response of Musca domestica L. to Mintostachys verticillata essential oil, (4R)(+)-pulegone and menthone. Fitoterapia 2012, 83, 336-342. (2) Palacios, S.; Bertoni, A.; Rossi, Y.; Santander, R.; Urzúa, A. Efficacy of Essential Oils from Edible Plants as Insecticides Against the House Fly, Musca Domestica L. Molecules 2009, 14, 1938-1947.