Mosquito repellent activity of oils from Vitex negundo Linn. leaves.

Oil obtained from stream distillate of V. negundo leaves was fractionated by column chromatography. Mosquito repellence activity, as evaluated against Aedes aegypti was mainly confined to the most polar fractions. The protection period against mosquito bites by polar fractions ranged between 1-3 h. However, the mean protection period values of these fractions did not show significant increase in the subsequent subfractions.