Evaluation of the antioxidant activity of biologically-active compositions based on plant metabolites produced by in vitro cell cultures

Free radicals can cause oxidative stress in the body, which, in turn, leads to various diseases such as cardiovascular diseases, diabetes, Alzheimer’s disease, Parkinson’s disease, and others. To protect against the destructive effects of radicals, living organisms utilize antioxidants. One of the most important classes of antioxidants is polyphenols. The primary effect of polyphenols on the body is associated with their ability to capture and neutralize free radicals, as well as reactive oxygen and nitrogen species. This study focuses on investigating the antioxidant activity (AA) of polyphenols and their compositions based on rutin, quercetin, and trans-cinnamic acid, produced by in vitro cell cultures, with the aim of developing dietary supplements with geroprotective properties. The AA of the studied substances was assessed using the ABTS and DPPH free radical scavenging methods. The study established that, according to the ABTS method, AA decreases in the order of quercetin > rutin > trans-cinnamic acid, while according to the DPPH method, the order is rutin > quercetin > trans-cinnamic acid. Among the tested mixtures, the highest AA was observed in mixture No. 8 and mixture No. 3, regardless of the assessment method. Consequently, to achieve the highest AA in a mixture, a higher content of quercetin and a minimal amount of trans-cinnamic acid should be included, while the optimal amount of rutin could not be determined. It is assumed that the amount of rutin should be at least equal to the amount of trans-cinnamic acid and ideally equal to the amount of quercetin. Thus, when developing dietary supplements with high AA, it is more advisable to include only quercetin rather than mixtures that also contain rutin and trans-cinnamic acid.