In vitro antibacterial activity of propolis extracts on 12 different bacteria in conditions of 3 various pH values

This research investigated the effects of propolis extracted by 5 different solvents and aged for 7 days on twelve species of bacteria classified into four groups according to their pathogenicity in slightly acidic (pH=6), neutral (pH=7) and slightly alkaline (pH=8) environments. Propolis extracted by the examined solvents had antibacterial effects. The strongest effects on the growth of all tested microorganisms, except on the bacteria of the Salmonella genus, regardless of the pH value of the environment, were exerted by propolis extracted by ether, acetone, toluol and chloroform. In some cases the antibacterial action of propolis was best in a slightly acidic environment (pH=6).