Evaluation of the antioxidant activity and capacity of some natural N(6)-substituted adenine derivatives (cytokinins) by fluorimetric and spectrophotometric assays.

•Cytokinins are N6-derivatives of adenine endowed with hormonal activity in plants.•Cytokinins show biological activities related to antioxidant properties.•The antioxidant activity of four cytokinins has been evaluated by different assays.•Each cytokinin shows a specific antioxidant activity, depending on N6-substitution.•The antioxidant activity can contribute to the biological role of cytokinins.