DEVELOPMENT OF HERBAL MOSQUITO REPELLENT FORMULATIONS

The present study reports the studies directed towards the development of safe and efficient herbal mosquito repellent formulations obtained by mixing hexane extract of Azadirachta indica seeds, hexane/ethanol extract of Vitex negundo leaves, essential oils from Ocimum sanctum leaves, Curcuma longa rhizomes and Citrus sinensis peels and essential oils of Cymbopogon nardus leaves, Eucalyptus globules leaves and Syzygium aromaticum buds purchased from the market. 1 ml of 10% (v/v%) extract / essential oil containing ethanol solutions prepared using each plant extract / essential oil was tested for mosquito repellent activity using arm-in-cage method. A volunteer’s forearm rubbed with 1 ml test solution was exposed to 20 blood-seeking mosquitoes and the number of mosquitoes that aligned or biting the arm was recorded in each minute for five minutes. Analysis was carried out as a triplicate and mosquito repellent activities were found to be in the order: Cymbopogon nardus and Eucalyptus globulus (100%) >Ocimum sanctum (97.94%) > Syzygium aromaticum (95.81%) > Citrus sinensis (93.75%) > Curcuma longa (89.56%) > Vitex negundo (85.44%) > Azadirachta indica (81.25%). Outdoor and indoor field trials on mosquito repellent gel and mosquito repellent spray prepared containing 16% (v/v%) active ingredients were conducted separately on two days from 5 am to 11 am by application on volunteers’ legs. 100% mosquito repellency up to six hours was observed for the gel and the spray for outdoor and indoor field trials.