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Journal of Chemistry
Volume 2013 (2013), Article ID 864095, 7 pages
Research Article

Effects of Tannin Extract from Gongronema latifolium Leaves on Lipoxygenase Cucumeropsis manii Seeds

Department of Biochemistry, University of Nigeria, Nsukka 410001, Nigeria

Received 15 December 2011; Accepted 18 June 2012

Academic Editor: Charlotte Hurel

Copyright © 2013 Sabinus O. O. Eze and Bennett C. Nwanguma. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Lipoxygenase (EC was partially purified from germinated seeds of Cucumeropsis manii to a purification fold of 47.14, enzyme activity recovery of 72.18%, and specific activity of 326.25 units/mg protein, using a three-step process of centrifugation, ammonium sulphate precipitation and gel filtration. Kinetic properties show maximum activity at pH 6.0 and at optimum temperature of 40°C. Inhibitory effects of the extract from Gongronema latifolium and two other known antioxidants: ascorbic acid and propyl gallate on lipoxygenase from Cucumeropsis manii were studied. Result shows presence of inhibition with IC50 of ±  g/L, ±  g/L and ±  g/L for the extract from ascorbic acid and propyl gallate, respectively. The extract when compared to the other antioxidants exhibits a competitive mechanism of inhibition. This tannin extract could be included during food processing as preservative against food deterioration that might be caused by oxidative enzymes such as lipoxygenase.