Antioxidant and hemagglutinating activity of polyphenols extracts from four legumes

Resumen

Legumes are an important source of proteins and carbohydrates, but they are also a good source of components of functional interest, such as polyphenols, that are synthesized by plants in response to microbial infections and environmental stress. Plant polyphenols are well known functional compounds with antioxidant and antiproliferative properties. Polyphenols are amphipathic molecules that may bind to proteins and lipids through hydrophobic and polar interactions. By these interactions the agglutination of liposomes and bacteria by polyphenols have been reported. Also, it has been described that the interaction of polyphenols with cell membranes erythrocytes enhances the antioxidant capacity of these cells (Koren et al., 2010). We have studied the antioxidant and erythrocytes agglutinating activity of seed polyphenols of four widely consumed legumes: lentil (Lens culinaris), broad bean (Vicia faba), chickpea (Cicer arietinum) and bean (Phaseolus vulgaris). Antioxidant activity, measured with the beta-carotene bleaching method, showed that lentil polyphenols possessed highest antioxidant activity. The erythrocyte agglutinating activity of these polyphenols extracts was also investigated. Lentil polyphenols showed complete agglutination of erythrocytes. Using lentil polyphenols extract, we determined the minimum concentration at which positive agglutination was observed, which corresponded to 2.42 μg bound polyphenols/mg erythrocytes. These results demonstrate that legume polyphenols are able to agglutinate erythrocytes in vitro, although due to the high concentrations that are required, polyphenols more probably do not agglutinate erythrocytes in vivo. Lentil polyphenols showed the complete agglutination of erythrocytes, hence, these polyphenols are very well suited to enhance antioxidant protection of human cells or bacteria from the gut.

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