A novel polymeric material with antioxidant properties and suitable for ophthalmic application was synthesized by free radical grafting reaction between 2-hydroxyethyl methacrylate and quercetin. The presence of quercetin in the polymeric chain was confirmed by FT-IR and UV-Vis analyses, while an estimation of the amount of quercetin bound per gram of polymer was obtained by the Folin-Ciocalteu...

In the current study, changes in health-promoting substances (phenolics and flavonoids) and antioxidant activity of carrot and mango beverages during storage at 25 and 35°C for 30, 60 and 90 days were investigated. The total phenolic content was determined using Folin–Ciocalteu method. The antioxidant activity was based on the evaluation of free–radical scavenging activity (FRSA) using DPPH rad...

We describe a reversed-phase HPLC method that uses gradient elution and diode array detection to determine four biologically active phenolic constituents of red wines: gallic acid, trans-resveratrol, quercetin and rutin. The method permits direct injection without sample pre-treatment. ODS Hypersil served as the stationary phase; the gradient was formed by acetic acid, methanol, and water. Each...

The aim of this work was to compare determination of quercetin concentration using HPLCUV/VIS method with antioxidant properties of selected red wines. Typical Slovenian wine varieties like “Merlot”, “Refošk”, “Barbera”, “Cabernet Sauvignon”, “Teran”, “Blue Pinot” and “Blue Frankish” were chosen. We applied the conventional Folin-Ciocalteu spectrophotometric method for determination of the tota...

Antioxidant properties of the principal biogenic amines were determined in vitro by four analytical methods—Folin Ciocalteu, DPPH, enzymatic and inhibition of lipid peroxidation—in order to avoid possible measuring-method linked mistakes. Different results are obtained, depending on the parameters that each of them measures. The combination of the data indicates that all examined amines show an...

In the present study experiments were carried out to determine the total phenolic content and their comparative antioxidant activities in relation to phenol content employing Folin-ciocalteu, DPPH, and ABTS assays of the different solvent extracts of the plant S. macrosperma. It was found that on an average, the plant extract with higher levels of phenol content had higher antioxidant activity....