Chemical composition, antioxidant and antibacterial activity of different extracts of poplar type propolis

Abstract

Chemical composition, antioxidant activity and invitro antibacterial activity of propolis from the central, continental part of Croatia were studied. Propolis hydro-ethanolic extracts (PHEE), prepared using three different methods and two solvent mixtures contained high amounts of flavonoids (20.95–28.11 % TIC), aromatic acids (8.17–15.91 % TIC) and their esters (9.27-11.91 % TIC). The PHEE obtained in this study showed high antioxidant activity (DPPH IC50 values from 9.96–19.95 µg/ml and FRAP 38.0–41.9 mM Fe2+/mg PHEE). Despite differences in composition, the PHEE samples exhibited significant antibacterial activities, affecting tested strains of Staphylococcusaures, Enterococcusfaecalis, Escherichiacoli and Moraxellacatarrhalis. The use of different solvent ratio and extraction procedures selectively increases or decreases the content of specific propolis components in the extract which can have a beneficial effect on the application of propolis extracts.