Detection of damage to DNA and antioxidative activity of yeast polysaccharides at the DNA-modified screen-printed electrode

A simple procedure for the voltammetric detection of the DNA damage and antioxidants protecting DNA from its damage using a disposable electrochemical DNA biosensor is reported. The carbon-based screen-printed electrode (SPE) modified by a surface layer of the calf thymus double stranded (ds) DNA was used as a working electrode in combination with a silver/silver chloride reference electrode and a separate platinum auxiliary electrode. The [Co(phen)3]3+ ion served as the dsDNA redox marker and the [Cu(phen)2]2+ and [Fe(EDTA)]− complex compounds were used as the DNA cleavage agents under the reduction by a chemical reductant (ascorbic acid). Four yeast polysaccharides with different chemical structure were investigated as the antioxidants within the concentration range of 0.05–4 mg ml−1 in the cleavage mixture. A remarkable antioxidative activity of polysaccharides in order mannan (Candida krusei)>extracellular glucomannan (Candida utilis)>mannan (Candida albicans)>glucomannan (C. utilis) was found which is in agreement with that refered to trolox (a structural derivative of α-tocopherol) and determined by photochemiluminescent method.