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Electrochemical DNA-based biosensor for the evaluation of antioxidant activity of some hydroxycinnamic acids

An electrochemical DNA-based biosensor composed of the screen printed carbon electrode modified with carboxylated single-walled carbon nanotubes [1] and dsDNA, dsDNA/SWCNT-COOH/SPCE, was applied to assessment of the antioxidant activity of some hydroxycinnamic acids. Hydroxycinnamic acids are group of polyphenolic compounds widely spread in plants as fruits and vegetables represented mainly by caffeic, ferulic, and chlorogenic acids. They are present in the form of derivates of quinic acid. The electrochemical biosensor was first incubated in the mixture of a DNA cleavage agent created by the Fenton type reaction without or with the addition of some hydroxycinnamic acid. After the incubation, the degree of dsDNA deep degradation was determined applying cyclic voltammetry of the DNA redox indicator [Fe(CN)6]3-/4- [2]. The antioxidant activity of hydroxycinnamic acids was evaluated using the normalized change of the indicator voltammetric responses ΔIrel and Δ(ΔEp, rel) [3, 4]. The obtained results have shown that the addition of hydroxycinnamic acids to the cleavage agent significantly reduces the degree of DNA degradation. The investigated caffeic (CA) and dicaffeoylquinic acids, diCQAs, have exhibited the portion of survived DNA of about 70% comparing to 20% in their absence.

electrochemical DNA-based biosensor ; cyclic voltammetry ; hydroxycinnamic acids

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