African Journal of Biotechnology Vol. 5 (10), pp. 901-906, 16 May 2006   

ISSN 1684–5315 © 2006 Academic Journals        

Full Length Research Paper

Chemical composition and insecticidal properties of the underutilized Jatropha curcas seed oil

Adebowale, K.O.¹* and Adedire, C.O.

¹Department of Chemistry, University of Ibadan, Ibadan, Nigeria.

²Department of Storage Technology, Federal University of Technology, Akure, Nigeria.

*Corresponding authors E-mail: adebowale2003@yahoo.com.

Accepted 11 January, 2006

Abstract

The chemical composition and insecticidal activity of Jatropha curcas L. seed were evaluated using standard techniques. The oil content of the seed is high (66.4%). Triacylglycenol was the dominant lipid species, while the major triacyglycerol was 1,2-Dioleoyl-3-linoleoyl-rac-glycerol. Linolenic acid was the dominant fatty acid in the oil. Physico-chemical properties of the oil indicated that the acid value, fee fatty acids, peroxide value and iodine value were high. Ten seterols and thirteen tritepene alcohol was identified in the unsaponifiable fraction of the oil. Jatropha seed oil at various serial dilution ranging from 0% to 2% (v/w) at 0.5% intervals were evaluated for anti-ovipositional activity and long-term protective ability of treated cowpeas against the seed beetle Callosobruchus maculatus. The oil significantly (P< 0.05) reduced oviposition by C. maculatus in no-choice test in all the concentrations tested. The number of eggs laid by the seed beetle reduced from an average of 54. 33 ± 3.53 in the control to only 4.00 ± 1.53 in 2% oil-treated seeds. There was no adult emergency in all the oil. However in choice-tested seed, 6.67 ± 1.33 eggs were laid in cultures treated with 2% oil while 21. 67 ± 1.45 were laid in control cultures. In dual-choice tests, oviposition was significantly reduced at all the oil concentration evaluated. J. Curcas oil also offers a 12-week protection for treated seeds since there were neither seed damage nor adult emergency in treated cowpea seeds. The results of this study suggest J. curcas has antioviposition and ovicidal effects on C. maculatus therefore making it a vaiable candidate for incorporation into pest control program of gain legumes.

Key words: Natural insecticides, Jatropha curcas seed oil, unsaponifiable matter, Callosobruchus maculates.