Antioxidant Efficacy of Natural Ubiquinol Compared to Synthetic References – In Vitro Study

Graphical Abstract

CoQ10 is bioactive substance in two forms that play an important role in electron transport chain. In order to be effective antioxidant, ubiquinone must be reduced to ubiquinol. Antioxidant activity of naturally occurring Ubiquinol was studied. It has a slightly stronger antiradical activity than several synthetic antioxidants. Additionally, it has showed also strong ferric reducing power measured by in vitro spectrophotometric methods. According to the electron paramagnetic resonance’ measurements, α-tocopherol/ubiquinol mixture in specific concentration showed higher antioxidant activity as individuals.

Abstract

There are many studies dealing with the oxidized form (Ubiquinone) of coenzyme Q10, but only a little of its reduced form (Ubiquinol). Two yeast-based Ubiquinols (UQH₂_S, Sigma-Aldrich; UQH₂_K, Kaneka) were investigated for in vitro antioxidant efficacy compared to synthetic antioxidants. The antioxidant efficacy of UQH2_S and UQH2_K by the 2,2-diphenyl-1-picrylhydrazyl’ (DPPH) assay as well as by the 2,2’-azino-bis(3-ethylbenzthiazoline-6-sulfonic) acid’ (ABTS) assay was almost identical (IC50_DPPH/ABTS 0.387/0.226–0.219 mM, respectively). The values were higher (p<0.05) than that of α-tocopherol, Gallic acid, Butylhydroxyanisole, Butylhydroxytoluene. Ferric Reducing Antioxidant Power’ values for Ubiquinols (0.05–0.3 mM) were higher (p<0.05) than for the other antioxidants, except Gallic acid. According to the Electron paramagnetic resonance assay, the antioxidant activity of α-tocopherol/UQH₂_S mixture was higher compared to the individual antioxidant only in specific combinations.