Mosquito repellent

The aim of the present study was to investigate the potential toxic effects of bioallethrin-based Mosquito-Repellents (MR) in non-adult rats as well as to ascertain whether the antioxidant substances such as Vitamin C and Vitamin E + Selenium  have any roles in preventing such toxic effects or not. 100 rat pups were divided into four study groups (each group consists of 25 rat pups) as Group I (control), Group II (bioallethrin), Group III (Vit C+ bioallethrin) and Group IV (Vit E+selenium+bioallethrin).  The animals in Group II, III, IV were exposed to the vapor of heated tablets including 4.2% bioallethrin 8 hours/day for a period of ninety days in a room with a volume of 23 m3. Vit C was added at a concentration of 500 mg/L to the fresh drinking water of animals in Group III. Vit E+Selenium combination was administered intraperitonally to the animals in Group IV once weekly at a dose of 50 mg/kg. According to the results, it was determined that antioxidants, particularly combination of Vitamin E+selenium administration, may be beneficial at preventing toxic effects of bioalletrin in rat pups. As a conclusion, when bioallethrin based- MR is used, Vit E+Selenium combination can be advised to prevent the effects of bioallethrin.

The repellent activity of methanolic extract of flower buds (clove) of Syzygium aromaticum Linn. and its different fractions was screened against the dengue fever and yellow fever mosquito, Aedes aegypti L. at 4% concentration under laboratory conditions using human subject. The extract and main ethyl acetate soluble fractions were the most effective and showed 80% repellency for 4 hours while petroleum ether soluble sub-fraction of latter fraction gave 72% repellency for 4 hours. These samples were 50-60% effective for 9 hours. The results were compared with standard mospel. Furthermore, in the present investigation toxicity of the extract and fractions of clove was determined against 4th instar larvae of Ae. aegypti by using WHO method. The extract, ethyl acetate soluble main fraction and petroleum ether soluble sub-fraction showed mortality with LC50 320, 240 and 160 ppm, respectively after 24 hours of exposure. It was observed that toxicity decreased with the increasing polarity of the fractions. These results were compared with standard neem formulation, biosal showing LC50 = 400 ppm against the same mosquito Ae. aegypti.