Phenolic composition and in vitro antioxidant capacity of four commercial phytochemical products: Olive leaf extract (Olea europaea L.), lutein, sesamol and ellagic acid

► The in vitro antioxidant activity of four commercially available antioxidant preparations derived from natural sources was identified. ► Lutein, sesamol, ellagic acid and olive leaf extract showed potential as natural antioxidants. ► Antioxidant potency followed the order: ellagic acid > sesamol > olive leaf extract > lutein. ► The main phenolic compounds present in olive leaf extract were identified and quantified.