Characterization of water extract of propolis collected from different regions of turkey by HPLC, and determination of antioxidant potential

Propolis, a functional food, is a resinous substance that honey bees collect from certain parts of plants. The chemical composition of propolis depends on various factors such as the geographical and climatic characteristics of the region where it is collected, the plant species and the collection time during the year. The strong antioxidant activity of propolis is due to the its phenolic compounds. Extraction of propolis with water, which has been used in apitherapy in the recent years, provides an advantage over other solvents in terms of easy and safe use by individuals. In the present study, it was aimed to characterize the water extract of propolis samples obtained from different regions of Turkey and to determine their antioxidant potentials and compare them with each other. For this purpose, water extracts of propolis samples collected from various provinces in different regions of Turkey were prepared. Qualitative and quantitative analyses of propolis extracts were achieved with HPLC-DAD, a powerful chromatographic tool. At the same time, the antioxidant potentials of the extracts were compared with each other by performing total polyphenolic content, total flavonoid content and iron reducing power tests. It was seen that the results obtained from the test of total polyphenol and flavonoid content and iron reducing power between regions were compatible with each other. The highest total polyphenolic content, total flavonoid contents and iron reducing power values were found in those of the Eastern Anatolia region. In the analyzes made with HPLC-DAD, a higher amount of caffeic acid was found in all of the water extracts of propolis compared to other phenolics. There was no agreement between the regions in terms of chemical components. The highest amount of caffeic acid was found in the Eastern Anatolia region and the highest amount of chlorogenic and trans-cinnamic acid was found in the Mediterranean region. It was observed that the total polyphenol content and the iron reducing power were high in the extracts with high caffeic acid content. According to the results obtained from the study, it was concluded that propolis samples obtained from different regions showed differences both in terms of chemical component and antioxidant properties.