Antioxidant activities of different tissue extract of faba bean (Vicia faba L.) containing phenolic compounds

Polyphenols and tannins have implications for health and nutrition because of their antioxidant activities. Foods with high content of phenolics, such as fruits, vegetables, grains and legumes, show decreasing incidence of several diseases upon their consumption. However, there are limited reports on antioxidative properties of tannins present in legumes. Faba bean seed has been known for high content of condensed tannin which is attributed as one of the antinutritional factors in this highly proteinaceous pulse crop. Therefore, the objective of this study was to estimate and characterize the phenolic compounds in different tissues of this underutilized pulse and their antioxidative activities. Fairly good amount of phenolics were observed in all tissues extract which was quite evident from their high FRAP (Ferric reducing antioxidant power) value. It was further, observed that the extract prepared from its seeds presented a potent radical scavenger activity as indicated by its high capacity to reduce the free radical diphenylpicrylhydrazyl, whereas the tannin-free extract indicated loss of antioxidative activities. The seed extract also interacted with superoxide anions, hydroxyl radicals as well as the oxidant species, hydrogen peroxide. Thus, our results provide evidence that the extract prepared from different tissues of faba bean shows antioxidant and radical scavenging activities largely because of its condensed tannins (proanthocyanidins).