The role of the mono-oxygenases in the detoxification of the insecticides 1,8-cineole and DDVP in Pediculus humanus capitis

TOLOZA A. & M.I. PICOLLO

Urgup, Cappadocia

Congreso; 9. Fourth International Conference on Phthiraptera (ICP4); 2010

International Society of Phthirapterists

During past decades, chemical control against the head louse Pediculus humanus capitis De Geer, has been based in the application of products containing permethrin. The repetitive overuse of pediculicides has resulted in the development of high levels of resistance to one or more of these products worldwide, and in the search of  alternative insecticides like the essential oils components obtained from aromatic plants (e.g. 1,8-cineol). In an afford to find effective tools to reduce pyrethroid-resistant and increase the activity of monoterpenes in head lice populations, we studied the synergistic effect of the piperonyl butoxide (PBO) on the pediculicidal activity of the monoterpenes 1,8-cineole and the organophosphate DDVP. The head louse population used in this study had a resistant ratio to permethrin of 40, partially due to the increased enzymatic activity of the cytochrome P450. The methodology employed here consisted of the topical application of the PBO on lice, followed by the exposition to the vapor phase of the compounds. The addition of PBO significantly increased the toxicity of either 1,8-cineole or DDVP. The present study indicates the importance of the microsomal monooxygenases (cytochrome P450) in the degradation of the monoterpenes like the 1,8-cineole. This suggests that a possible combination of monoterpenes or phytochemicals with PBO into a formulation might provide a better control to insecticide-resistant populations of head lice.