Influence of the extraction procedure on the antioxidative activity of lentil seed extracts in a β-carotene-linoleate model system

Phenolic compounds were extracted from lentil seeds using three solvent systems: 80% (v/v) acetone, 80% (v/v) methanol, and 80% (v/v) ethanol. Each extract was subsequently separated into two fractions by chromatoghraphy on a column with Toyo Pearl HW-40 using water (fraction I) and methanol (fraction II) for elution. Antioxidative activity of extracts and their respective fractions were examined in a β-carotene-linoleate model system. All three extracts exhibited similar antioxidant activity. Considering the level of phenolic compounds in extracts it seems that phenolic compounds from the acetone extract were less active than those from either the methanolic and ethanolic ones. Because the content of phenolics was about 16-fold lower in fraction I of the methanolic and ethanolic extracts compared to fraction II, the phenolics in fraction I of the methanol and ethanol extracts from lentil seeds are much more active than these in fraction II. A stronger antioxidant activity of fraction I from the acetone extract compared to the crude acetone extract was observed during the latter incubation stage. The reason was a relatively high level of phenolic compounds in this fraction. UV spectra confirmed that the phenolic compounds from the acetone extract were different compared to methanolic and ethanolic extracts.