Investigation of radical scavenging and ferrous ions chelating activity of Turkish propolis extracts

Propolis is an important bee product, rich of polyphenolic compounds and flavonoids, it has antibacterial, antitumoral, anti-inflammatory, antioxidative, antimutagenic properties and changeable composition according to climate and geography of harvest region, and is used as a natural drug with other useful activities. Flavonoids are polifenolic compounds where they naturally take place in drinks such as fruits, vegetables, tea, wine, juice. These compounds are secondary plant metabolites, and they compose an important part of human diet as they can not be synthesized by human. Its biological activity shows via combining heavy metal ions and polymers, catalyzing electron transport and scavenging free radicals. Free radicals cause oksidative damage on biomolecules. In this study iron chelating activity and free radical scavenging capacity of extracts of our regional propolis in different solvents were investigated. Propolis extracts in ethanol, methanol and DMSO with 25 mg/mL and above concentrations were found to have metal chelating effect over 90 %. Radical scavenging activity was determined with DPPH method. Extracts in ethanol and methanol with 125?g/mL and above concentrations demonstrated scavenging effect over 90 %. Extracts in DMSO with same concentrations were found to have scavenging activity as 73 %. Antioxidant effects of propolis were reported in previous studies. In this study known antioxidant effect of propolis was investigated via in vitro ROS measurement if it was due to possible mechanisms including metal chelating and radical scavenging capacity or not. After a recruitment time for 4 hours in fibroblasts damaged with 300?M t-BHP 200?g/ml propolis reduced ROS amounts compared with the positive control by radical scavenging effect and more effective by metal chelating activity. Key Words: Propolis, Metal chelating, Free radical, CM-H2DCFDA, Fibroblast cell