. Preparation of Plant Extracts. The leaves (2 kg each) were
air dried in shade for 15–30 days. The dried leaves were
then powdered mechanically using a commercial electrical
stainless steel blender. One kg of powdered leaves was
extracted successively by maceration using nonpolar to polar
solvents, namely, hexane, diethyl ether, dichloromethane, and
methanol. In each solvent, the plant material was soaked for
48 h at 35∘
C and filtered twice using Whatman number 1
filter paper to obtain the extract, and to the residue the same
solvent was added again.The procedure was repeated twice to
obtain maximum extract. The extracts were concentrated at
reduced temperature using a rotary vacuum evaporator and
stored at a temperature of 4∘
C. One gram of the concentrated
plant extract was dissolved in 100 mL of 1 : 1 acetone : dimethyl
sulfoxide (DMSO) and considered as 1% stock solution. From
this stock solution, varying concentrations of each extract was
prepared and these solutions were used for larvicidal bioassay.
All chemicals used in this study were of extra pure grade and
were obtained from Sisco Research Laboratories PVT. Ltd.,
India