Antioxidant activity of faba bean extract and fractions thereof

Phenolic compounds were extracted into 80% (v/v) acetone. The crude extract so obtained was separated into fraction of low-molecular-weight compounds (Fraction Ⅰ) and a fraction of condensed tannins (Fraction Ⅱ) using Sephadex LH-20 column chromatography with ethanol and acetone/water (1:1, v/v) as respective mobile phases. The antioxidants activities of the crude extract and fractions thereof was investigated in an emulsion system and using ABTS, DPPH, and reducing power assays. Fraction Ⅱ exhibited a higher antioxidant efficacy than those of the crude extract and Fraction Ⅰ. In the crude extract, 21 compounds, namely phenolic acids (gallic, p-hydroxybenzoic, protocatechuic, p-coumaric, ferulic), flavonoids (catechin, epigallo catechin, kaempferol, apigenin, and luteolin derivatives), gallate procyanidins, vanillin, protocatechuic aldehyde, and tryptophan were identified by HPLC-DAD-MS. Gallate procyanidin dimer, gallate procyanidins, and acetylated kaempferol hexose were the major phenolics present in the extract.