Antioxidant activity of a red lentil extract and its fractions

Int J Mol Sci. 2009 Dec 23;10(12):5513-5527. doi: 10.3390/ijms10125513.


Phenolic compounds were extracted from red lentil seeds using 80% (v/v) aqueous acetone. The crude extract was applied to a Sephadex LH-20 column. Fraction 1, consisting of sugars and low-molecular-weight phenolics, was eluted from the column by ethanol. Fraction 2, consisting of tannins, was obtained using acetone-water (1:1; v/v) as the mobile phase. Phenolic compounds present in the crude extract and its fractions demonstrated antioxidant and antiradical activities as revealed from studies using a beta-carotene-linoleate model system, the total antioxidant activity (TAA) method, the DPPH radical-scavenging activity assay, and a reducing power evaluation. Results of these assays showed the highest values when tannins (fraction 2) were tested. For instance, the TAA of the tannin fraction was 5.85 micromol Trolox eq./mg, whereas the crude extract and fraction 1 showed 0.68 and 0.33 micromol Trolox eq./mg, respectively. The content of total phenolics in fraction 2 was the highest (290 mg/g); the tannin content, determined using the vanillin method and expressed as absorbance units at 500 nm per 1 g, was 129. There were 24 compounds identified in the crude extract using an HPLC-ESI-MS method: quercetin diglycoside, catechin, digallate procyanidin, and p-hydroxybenzoic were the dominant phenolics in the extract.

Keywords: HPLC-ESI-MS; free radicals; phenolic compounds; red lentils; tannins.

MeSH terms

  • Benzaldehydes / chemistry
  • Chemical Fractionation
  • Free Radical Scavengers / chemistry*
  • Lens Plant / chemistry*
  • Phenols / chemistry
  • Plant Extracts / chemistry*
  • Tannins / chemistry
  • beta Carotene / chemistry


  • Benzaldehydes
  • Free Radical Scavengers
  • Phenols
  • Plant Extracts
  • Tannins
  • beta Carotene
  • vanillin