D. Talukder
BCSIR Laboratories, Rajshahi, Rajshahi-6206, Banglasesh.
A. Khatun
Department of Chemistry, University of Rajshahi, Rajshahi-6205, Banglasesh.
M. N. Islam
Department of Chemistry, University of Rajshahi, Rajshahi-6205, Banglasesh.
M. S. Islam
Department of Chemistry, University of Rajshahi, Rajshahi-6205, Banglasesh.
S. Zaman
Department of Chemistry, University of Rajshahi, Rajshahi-6205, Banglasesh.
A. B. M. H. Haque
Department of Chemistry, University of Rajshahi, Rajshahi-6205, Banglasesh.
Petroleum ether extracts; Z. cassumunar rhizome; Chromatography; Insecticidal activity; Tribolium castaneum adults
Rajshahi, Bangladesh.
Pest Management
Stock culture of T. castaneum was maintained in plastic containers and sub-cultures in beakers with the food medium at 30? ± 0.5? in an incubator. A standard mixture of whole-wheat flour with powdered dry yeast in a ratio of 19: 1 was used as food medium. The rhizomes of Bonada, Z. cassumunar were procured from different areas of Rajshahi, Bangladesh. The rhizomes were chopped off into small pieces and dried in a shade. Finally, it was dried in an oven at 40?. After drying these parts were crushed by using a cyclotech grinding machine. After crushing, the plant materials were extracted in a soxhlet apparatus separately with petroleum ether, acetone and methanol. The extraction process was carried out by refluxing the solvent for twenty hours. The solvents were evaporated in rotary vacuum evaporator at 40? under reduced pressure and the petroleum ether, acetone and methanol extracts were collected in small reagent bottle and preserved at 4? in a refrigerator. The concentrated peroleum ether extract was mixed with a small amount of column grade Silica gel, maintaing the ratio as: concentrated mass : Silica gel= 2:1 and dried in air. After drying, the mixture was powdered in a mortar. This powder was then ready for fractionation by column. The petroleum ether extract was prepared for column chromatography using mobile phase toluene, chloroform, ethyle acetate and methanol. The column was elute first with 100% toluene and increasing amount of chloroform and then increasing amount of ethyl acetate, finally methanol. Elute were collected in an amount of about 50mL in a series of conical flask. Elute of similar behaviour were combined together based on Thin layer chromatography analysis. There were seventy-eight serially fraction obtained from column chromatography which were combined in eight fraction were designated as: MN-1, MN-2, MN-3, MN-4, MN-5, MN-6, MN-7 and MN-8. Thin layer chromatography of the above eight fractions were observed. Then fraction, MN-1 was subjected to preparative thin layer chromatography using toluene: Chloroform solvent system. The separated bands were visualized by the use of UV light. Four sharp bands were marked with a pin and were collected in different 100mL beakers, which were numbered as M-1, M-2, M-3 and M-4. These four part were washed with petroleum ether, chloroform, ethyl acetate and methanol respectively and separated by small colum and designated as M1 N1, M1N2, M1N3, M1N4, M2N1, M2N2, M2N3, M2N4, M3N1, M3N2, M3N3, M3N4, M4N1 and M4N2. Fractions of M1N2, M2N2, M3N2 and M4N2 etc. and the content were dried. TLC behaviour of these fourteen fractions were observed. Residual film technique was used to test the mortality rate of the larvae and adults of T. castaneum. The doses were prepared by the mixing the requisite quantities of different solvent extract and different fraction of petroleum ether extract of Z. cassumunar with 10mL acetone or methanol. Methanol was used in the case of methanol extract because these extracts do not dissolve properly in acetone. The experimental doses were 78.60, 157.19, 314.38, 471.57 and 628.76 mg/cm 2 for all the solvents. The doses were prepared by mixing the requisite quantities of extracted materials with 1mL acetone or methanol. For testing the mortality, each dose with 1mL solvent was dropped on a petridish. After drying, three petridishes were taken each with forty adult insects considered as three replications. Other three petridishes contained only solvent and same number of insects considered as control. The experiment was performed at 30? ± 0.5?. The doses were calculated by measuring the weight of extracted materials in 01 ml of the solvent divided by the surface area of the petridish and it is converted in to mg/cm2. Mortality was assessed after 24, 48 and 72 hours of the treatment applied. The percentage of mortality was corrected using Abbott’s formula and LD50 values were determined by probit analysis.
Bangladesh J. Sci. Ind. Res. 50(2), 143-152, 2015
Journal