A steam volatile bioactive molecule from Ipomoea carnea leaves

Mosquitoes are the oldest human enemy and are well known vectors of several pathogens causing diseases. The study of biologically active materials derived from plant sources can act as larvicides, insect growth regulators, repellents and ovipositional attractants and have deterrent activities as observed by many researchers. Insecticides of plant origin are expected to be target selective and biodegradable leading to fewer harmful effects on human and other animals and are environmentally safe as compared to synthetic compounds. In recent years, essential oils have received much attention as potentially useful bioactive compounds against insects. The steam volatile mixture of Ipomoea carnea leaves was tested against two mosquito species, 4th instar larvae of Culex quinquefasciatus and Aedes aegypti. The bioassay of the mixture was investigated. It exhibited significant chronic mosquito-larval toxicities against the two vectors, so further separation and isolation is performed. The isolated molecule, alicyclic aromatic ester, has demonstrated enhanced activity than its crude fraction and original steam volatile extract. Experiments were carried out with 4th instar larvae (0-24 h old) of Aedes egypti and Culex quinquefasciatus which were cultured and maintained during the experiment at 80± 5% and relative humidity at 27± 2o. LC50 and LC 90 values for each sample were calculated.