Impact of essential oils on Musca domestica larvae: oxidative stress and antioxidant responses

The housefly (Musca domestica) is incriminated as a vector of many detrimental diseases like diarrhoea, cholera, etc. To combat its population below threshold levels many types of insecticides including essential oils (EOs) have been tested from time to time. However the insect has often shown some resistance to proliferate and reproduce continuously. In view of this objective, present study highlights the antioxidative responses of M. domestica larvae to Bay, Lemongrass and Tea tree EOs during a short-term exposure (24 h) to respective compounds. After treatment with EOs, the housefly larvae showed increased levels of Malondialdehyde (MDA) indicating increased lipid peroxidation due to tested oils. The Tea tree essential oil induced substantial increase in superoxide dismutase and glutathione peroxidase activities as compared to lemongrass and bay EOs. Moreover, Lemongrass EO was found to significantly affect the catalase activity depicting a value of 0.0733 ± 0.006 units per milligram of protein (U/mg protein). In case of glutathione reductase activity, higher effect was induced by bay EO exhibiting 0.0150 ± 0.001 U/mg protein which was preceded by tea tree compound. The observations of the present study signpost that M. domestica has evolved antioxidant defence mechanism to combat reactive oxygen species generated by short term exposure of LC50 concentration of tested EOs. Therefore proper optimization of EO concentration together with time of exposure of the insect becomes imperative for formulating organic insecticides against house fly populations.