Evaluation of the redox properties and anti/pro-oxidant effects of selected flavonoids by means of a DNA-based electrochemical biosensor

Abstract

Quercetin and rutin as well as catechin and epigallocatechin gallate were investigated, as widely distributed representatives of flavonols and flavanols, respectively, regarding their anti/pro-oxidant properties. The flavonoids are irreversibly oxidized at a dsDNA-modified screen-printed electrode within 0.368 to 0.449 V vs. SHE without binding to DNA. Using the DNA biosensor the detection scheme of a DNA prevention/degradation exploits the [Co(phen)(3)](3+) complex as an electrochemical DNA marker. Antioxidant activity of flavonoids was tested in a model cleavage mixture composed of 5 x 10(-7) mol L(-1) [Cu(phen)(2)](2+) as the catalyst, 1 x 10(-3) mol L(-1) ascorbic acid as the chemical reductant and atmospheric oxygen as the natural oxidant where reactive oxygen radicals are generated. The antioxidant activity increases with the concentration of flavonoids reaching a maximum where pro-oxidative behaviour becomes of importance. The pro-oxidant potency of flavonoids depends on the presence of atmospheric oxygen and follows the order quercetin>rutin>epigallocatechin gallate>catechin.

Voltammetric Detection of Antioxidative Properties of Flavonoids Using Electrically Heated DNA Modified Carbon Paste Electrode

“…No prooxidative effects of flavonoids to DNA have been observed at the concentrations used. This is in agreement with a recent investigation of flavonoids effects at the DNA modified screen-printed electrode where a prooxidative behaviour was found only at high concentration of the phytochemicals [27]. …”

DNA-based biosensor for the electrocatalytic determination of antioxidant capacity in beverages

“…In recent years, several electrochemical DNA-based sensors have been developed in order to assess the antioxidant capacity (Labuda et al, 2002(Labuda et al, , 2003Mello and Kubota, 2007;Qian et al, 2010). UV irradiation (Liu et al, 2005) or most commonly Fenton reaction were used for OH…”

“…On one hand, the use of redox active dsDNA intercalators allowed evaluating the oxidative damage on dsDNA layers because of a significant decrease in the current intensity of the intercalator upon strand scission (Labuda et al, 2002(Labuda et al, , 2003Liu et al, 2005). On the other hand, the intrinsic electroactivity of DNA can be exploited.…”

An Electrochemical DNA Biosensor for the Detection of the Apa I Polymorphism in the Vitamin D Receptor Gene Using Meldola's Blue as a Hybridization Indicator

“…Additionally, the carbon electrodes have been also used with several noncovalently interacting or covalently bound labels. [14,40,41]. Panke et al [31] reported a competitive binding protocol and used methylene blue as electroactive label for the determination of DNA single base mismatches in combination with differential pulse voltammetry.…”