Determination of antioxidant activity, phenolic quantification of four varieties of fenugreek Trigonella foenum graecum L. seed extract cultured in west Algeria

The differences between the metabolic content cultivars and their wild relatives are not only consequences for breeding and quality of food, but also for the study area increasingly growing wild introgression. Trigonella foenum graecum L. is a medicinal plant that is widely used in Algerian folk medicine. This work is a phytochemical study determining and comparing the amount of phenolic compounds and antioxidant activity of four different cultivars of fenugreek seeds grown at the National Institute for Agricultural Research (INRA) in Lamtar (Sidi Bel Abbes, North West Algeria). The total phenolic content in the extracts was determined using the Folin-Ciocalteu reagent and it ranged between 1,613 and 2,083 gallic acid equivalents mg/g of extract. The quantification of flavonoids was performed by a method with aluminum trichloride and sodium hydroxide, it varied between 1,847 to 3,778 catechin equivalents mg/g. The condensed tannins were determined by the method with vanillin under acidic conditions where contents expressed as catechin equivalent were about 0,730 to 1,051 mg/g. The antioxidant activity was analyzed in vitro using the DPPH reagent; among the varieties studied, the 2087 variety showed the highest antioxidant activity.