The Effects of Different Extraction Methods and Solvents on Antioxidant Properties of Propolis

Abstract

Propolis is a complex sticky substance produced by the honey bees (Apis mellifera) from the resinous materials they collect from various parts of plant and used by the bees to defend their hives from pathogenic microorganisms. This research aimed to compare the antioxidant properties of propolis extracts produced by using different solvents and extraction methods. The method used in the extraction stage is of great importance as the amount and quality of the bioactive components in the final product are directly affected by the extraction method applied. To obtain propolis extracts, both classical and ultrasonic extraction methods were used with distilled water and 20% propylene glycol-distilled water as solvents. Folin-Ciocalteau method was used to record the total phenolic content of propolis extracts. In this study, to measure the antioxidant activity of extracts, three methods were used that are FRAP, DPPH, and ABTS. Moreover, the aluminum chloride colorimetric method was used for total flavonoid content analysis. According to analysis, brix values recorded between 14.90-27.50 for classic method and 14.40-16.50 for ultrasonic method. The total phenolic content calculated as 721.31-14419.46 mg GAE/L for classic method, and 1212.32-33621.70 mg GAE/L in ultrasonic method. Also, the total amount of flavonoid content was measured as 1137.52-24884.70 mg QE/L extract in ultrasonic method, and 2144.77-74021.42 mg QE/L extract in classic method. DPPH radical scavenging activity of the samples were calculated as 0.46-15.21 IC50 µl/ml in classic method, and 1.36-31.86 IC50 µl/ml in ultrasonic method, ABTS+ values changed from 0.09-2.71 IC50 µl/ml in classic method, and 0.21-4.64 IC50 µl/ml in ultrasonic method, and FRAP values measured between 29.22-639.43 µM TE/g in ultrasonic method, and 54.72-1783.02 µM TE/g in classic method. More studies and analysis are needed to investigate the effects of solvents and extraction methods on propolis extracts, as well as on the antioxidant properties of these extracts.