• 2,2-diphenyl-1-picrylhydrazyl;
  • Algerian propolis;
  • antibacterial activity;
  • antioxidants;
  • electron spin resonance


The aim of this study was the investigation of antimicrobial and antioxidant activities of different ethanolic extracts of propolis (EEP) collected from north-western Algeria. Total polyphenols and flavonoids contents of extracts were measured. The UV absorption spectrum showed and confirmed their polyphenols constituents. All EEPs exerted antibacterial activity against Gram-positive bacteria, but no effect on Gram-negative bacteria. The minimum inhibitory concentration (MIC) of EEPs ranged from 0.01% to 2.6% v/v. The antioxidant activity was measured using ferric-reducing power (FRAP), 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging and ESR methods. Propolis TIA-2 and MOH-MAS samples showed the highest antioxidative capacity, after 35 min, while TIA-1, NED-TL and SFS-SBA samples showed the highest antioxidative potential of measured EEPs, after 3 min. TIA-2 sample showed the highest antibacterial, antioxidant activity and highest DPPH free radical-scavenging activity as well as the highest polyphenols and flavonoids content, compared with other propolis samples.