STUDIES ON MOSQUITO REPELLENT ACTIVITY OF CYMBOPOGON CITRATUS (LEMON GRASS) USING HUMAN VOLUNTEERS
Background: Safety concerns over the use of chemical based pesticides are provoking intense studies and application of bio pesticides in disease control and agriculture. Aim: This qualitative study was aimed at testing the repellent efficacy; and suitability of Cymbopogon citratus (Lemongrass) for the development of natural product based mosquito repellent. Method: Cymbopogon oil (75ml) was extracted from 200g of fresh Lemongrass leaves using Soxhlet method with n Hexane as solvent. Human volunteers were topically treated with 2ml and 6ml of Cymbopogon oil applied on exposed areas of the body at night; and observed for 4hrs 30mins. Direct test on mosquitoes in captivity was conducted using a 2 chambered insect box treated with 4 ml of oil in one chamber. Results: Human subjects were free from mosquito bites for 3 hours. Mosquitoes in captivity exhibited active movement away from oil treated chamber of the box within the first minute of application; 43% repellency and 100% mortality were recorded after 18 minutes. Conclusion: Findings suggest that Cymbopogon citratus extracts could be used for the production of potent chemical free and safe mosquito repellent and insecticide for vector control in the fight against malaria and other mosquito vectored diseases. However further studies and qualitative analyses are necessary to determine suitable concentrations for human topical application.