What Should Be the Ideal Solvent Percentage and Solvent-Propolis ratio in the Preparation of Ethanolic Propolis Extract?

The biological activity of propolis is mostly due to its polyphenols. Raw propolis is consumed after being extracted in various solvents, ethanol being the most commonly used. However, the ideal percentage and ratio of ethanol for use in the preparation of propolis extracts are uncertain. The aim of this study is to compare the phenolic compositions and antioxidant activities of propolis extracts extracted with different ethanol concentrations and extraction conditions. Two different extraction methods were used, normal and ultrasonic extraction. The propolis extracts were evaluated in terms of total phenolic content, total flavonoid content, ferric reducing/antioxidant power,1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, and phenolic compositions using RP-HPLC–PDA. The propolis extracts with the highest activity were determined beforehand by preparing ethanol–water mixtures at different percentages, ranging from 0 to 99.9%. The most suitable propolis-to-solvent ratio was then determined. The optimum ethanolic percentage varied between 60 and 70%, the ultrasonic extraction process increased the efficiency, and the ideal solvent-propolis ratio (w/v) ranged between 1:5 and 1:10.