Lupinus seeds are characterized by elevated contents of high quality protein, so they find uses in both human and animal nutrition. However, little is known about possible bioactive compounds that could be beneficial to health. Lunasin is a 43 amino acid residue peptide isolated by the group of Prof. de Lumen (University of California, Berkeley) from the albumin protein fraction of soybean. Its cancer chemopreventive properties have been demonstrated by in vitro and in vivo assays; currently other plants are being investigated as possible sources of this peptide. This study aimed to detect lunasin in two cultivated and two wild species of Lupinus. Lunasin detection using lunasin monoclonal antibodies was carried out on total protein extracts as well as soluble fractions of defatted flour from seeds with and without testa. Soy (Glycine max) seed extracts served as positive control. Results showed the presence of lunasin in G. max protein fractions of albumin, globulin, and glutelin. Lunasin was found in prolamins fraction of L. albus seeds with testa; whereas it was found in albumin and glutelin fractions of seeds without testa of L. montanus and L. campestris, respectively. Lunasin was not detected in protein extracts of seeds without testa of L. albus and seed with and without testa of L. mutabilis. Peptide bands of molecular weights greater than 25 kDa were detected in the fractions of albumin, globulin and glutelin of all evaluated Lupinus species, suggesting presence of lunasin-related peptides.

This work was funded by SIP-IPN (SIP 20090435) and by CONACYT (100808). O.J. Ramos H. is indebted to Instituto Politecnico Nacional (PIFI-IPN) and CONACYT for the fellowship awarded. K. Bermudez Torres, G. Sepulveda J. and A.R. Lopez L. thank EDI and COFAAIPN for support. B. Hernandez-Ledesma thanks European Commission and Spanish National Research Council by her Marie-Curie and JAE-Doc contracts.

Trabajo presentado a la 13th International Lupin Conference celebrada en Poznań (Polonia) del 6 al 10 de junio de 2011.

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