MOSQUITO REPELLENT ACTIVITY OF DELONIX ELATA (FABACEAE) LEAF AND SEED EXTRACTS AGAINST THE PRIMARY DENGUE VECTOR AEDES AEGYPTI (DIPTERA: CULICIDAE)

Dengue fever causes mortality and morbidity around the world, specifically in tropical and subtropical areas. As a consequence, the search for new anti-dengue agents from medicinal plants has assumed more urgency than in the past. Medicinal plants have been used widely to treat a variety of vector ailments such as malaria. The demand for plant-based medicines is growing as they are generally considered to be safer, non-toxic and less harmful than synthetic drugs. In the present study the repellent activity of hexane, benzene, chloroform, ethyl acetate and methanol extract of Delonix elata (D. elata) leaf and seed against Aedes aegypti (Ae. aegypti). One hundred three day old starved female Ae. aegypti mosquitoes were kept on a net cage (45 cmx30 cmx45 cm). The repellency was determined against Ae. aegypti mosquito species at three concentrations viz., 1.0, 2.5 and 5.0 mg/cm(2) under the laboratory conditions. Ae. aegypti were tested during the day time from 07.00 to 17.00 h. In this study, the plant crude extracts gave protection against mosquito bites without any allergic reaction. The repellent activity was dependent on the strength of the plant extracts. Among the tested solvents the maximum efficacy was observed in the leaf and seed methanol extracts. The highest concentrations of 5.0 mg/cm(2) provided over 180 and 150 min protection, respectively. Overall, the crude methanol extract of D. elata showed an excellent potential to develop newer and safer control tools the dengue vector mosquito Ae. aegypti.