Estudo fotoquímico da ação anti-radicalar de compostos polifenólicos empregando espectrofotometria e HPLC-UV

Abstract

The interest in antioxidants has increased considerably in recent years as molecules that reduce lipid peroxidation may minimize or inhibit the oxidative damage caused to DNA, proteins and carbohydrates. Flavonoids, a group of secondary metabolites widely distributed in the plant kingdom, have properties of anti-inflammatory, antibacterial, antiviral, anti-allergic and anti-tumor, in addition to possessing antioxidant and free radicals to inactivate them and prevent oxidative damage at cell level. It is believed that the biological activity of flavonoids is due to its antioxidant properties. Due to the great importance given today to free radicals and antioxidants, there is a strong demand for analytical techniques able to identify and quantify these two groups of compounds. This work describes the study of anti-radical power of the flavonoids kaempferol, fisetin, quercetin, quercitrin, myricetin and rutin against UV radiation and HO radical. The method used was based on artificial photochemical generation of HO radicals by photolysis of H2O2. The flavonoids studied were photpstable towards UV radiation and efficient in the fight against HO radical. The flavonoid quercitrin was the most active compound, followed by rutin, kaempferol, fisetin, quercetin and myricetin. The proposed methodology allows for quantitative comparison of the antiradical action of the antioxidants based on the reaction kinetics of the species with the HO radical. Similarly, the study in vitro the interaction between HO radicals and plant extracts with antioxidant character can be accomplished by the proposed method.