Abstract
The extensive use of synthetic insecticides to control vector-borne diseases has caused increased insect resistance, adverse health effects on humans and the ecosystem. Currently, a new nanotechnology strategy is being considered to develop new green-nano-friendly insecticides. This is the first study for the formulation of Mentha spicata essential oil (EO) nanoemulsion and its application against Culex pipiens, and housefly, Musca domestica. Acute oral toxicity of nano and normal emulsions was studied on rats. The results of gas chromatography-mass spectroscopy (GC-MS) analysis showed that the total identified compounds 95.18 % comprised 28 compounds. These included 1,8-Cineole (19.55 %), menthol (14.4 %), 1-p-menthen-8-yl acetate (6.42 %), 4-terpineol (6.28 %), alpha-terpineol (5.38 %), alpha-pinene (5.26 %), beta-pinene (4.72 %),p-cymene (3.52 %) and delta 3-carene (3.09 %) as the major components. Nanoemulsion with droplet size 97.8 nm was obtained by ultrasonic emulsification for 10 min at ratio 1:1 (v/v) of mint EO and Tween 80. Emulsification conditions and nanoemulsion droplet size are correlated. Mint nanoemulsion showed a high larvicidal activity against C. pipiens (LC50, 43.57 mu g/mL) and M. domestica (LC50, 65.13 mu g/mL) compared with normal oil and lambda-cyhalothrin insecticide. Nanoformulation increased efficiency by 71.46 % and 52.0 % against C. pipiens and M. domestica, respectively. Nanoformulation had no toxic effects on the treated rats. Mint nanoemulsion is solvent-free, soluble in water, effective, safe, and eco-friendly. Therefore, it can be used to control C. pipiens, and M. domestica larvae as it is or by developing new capsules with controlled-release as a possible product.