Content of Phenolic Compounds and Antioxidant Properties in Seeds of Sweet and Bitter Cultivars of Lupine ( Lupinus angustifolius )

Abstract

The main purpose was to demonstrate differences in the total content of phenolic compounds, phenolic acids and to analysis differences in the antioxidant properties of extracts obtained from seeds of several narrow-leaf lupine cultivars (Lupinus angustifolius L.). The biological material consisted of seeds of four cultivars of narrow-leaf lupine characterized by different concentrations of alkaloids. The total content of phenolics was determined with the colorimetric method using the Folin-Ciocalteau reagent. Other determinations included the ability of seed extracts to scavenge DPPH^• radicals and ABTS^•+ cation radicals. The reducing power of the extracts was also determined. Chromatographic and qualitative separation of the phenolic compounds present in seeds was performed with the RP-HPLC method. Out of the four cultivars, the bitter narrow-leaf lupine produced seeds with the highest total content of phenolic compounds, which was also correlated with its antiradical characteristics. In the analyzed seeds were also found to contain three phenolic acids: ferulic, sinapinic and p-coumaric one.