Repellent activity of products containing deet, hipc, pmd and plant essential oils against coastal species of mosquito in phang-nga naval base, tsunami affected area

Abstract

The efficacy of 5 commercial repellents (2 products contained synthetic chemical compound as active ingredient, and the other 3 products contained botanical extracts as active ingredient) and 4 laboratory prepared products which had plant essential oils as active ingredient were evaluated against coastal species of mosquito in the Phang-Nga naval base after tsunami. A 10x10 Latin square design was used to randomize the test subjects for possible individual difference for mosquito attraction. One gram of each product was applied to each volunteer’s leg (from knee to ankle). Mosquitoes attracted to treated areas of human baits were observed and collected from 18:00 to 22:00 hours. All 5 commercial products, which each contained active ingredients as deet (di-methyl benzamide), HIPC (hydoxylethyl isobutyl piperidine), PMD (p-menthane diol), citronella oil, or turmeric oil and eucalyptus oil combination provided complete repellency throughout the observation periods of 4 hours. For the laboratory prepared products, each kind of plant essential oils (makaen oil, galangal oil and oil combination of qinghaosu, may chang and kaffir lime) was individually prepared as active ingredient in cream formulation. The preparation with oil combination was formulated into ointment. The formulated repellents gave complete protection for 2-3 hours. The results indicate that the repellent activity of the commercial products was better than the laboratory formulated products; however, 2-3 hours of repellency would be sufficient to protect against evening mosquitoes if people use them before retiring to sleep under a bednet. Locally formulated repellents with these natural essential oils could be useful in where low cost alternatives are needed and in places where native aromatic plants are grown.