Phenolic Content, Antibacterial and Antioxidant Activities of Moroccan propolis

Background: Propolis contains compounds with antibacterial and antioxidant capacities, such as phenolic compounds and flavonoids. The aim of this study was to investigate the antibacterial and antioxidant effects of six propolis samples from northern Morocco and to determine their content of polyphenols and flavonoids. Methods: The total polyphenols and flavonoids of Ethanol Extracts (EEP) were evaluated by colorimetric assays. To test the antibacterial activity, the well diffusion and micro-dilution methods were adopted. The kinetic of bacterial growth in the presence of EEP was tested. The antioxidant activity was evaluated using three techniques: reducing power, β-carotene bleaching test, and DPPH scavenging capacity assay. Results: The EEPs were found to have high total phenolic content (65.09 - 122.00 mg GAE/g) and flavonoids (41.95 - 50.44 mg QE/g). The screening of the antibacterial activity showed that all tested bacteria were sensitive to EEP except Escherichia coli. The inhibitory zones varied from 11.50 ± 0.70 to 32.00 ± 0.70 mm, and MIC and MBC ranged from 0.07 to 5 mg/mL and 0.07 to >5 mg/mL, respectively. The antioxidant activity was proportional to the phenolic content of propolis. The IC50 varied from 48.70 to 156.00 mg/mL and the RAA% ranged from 75.07 to 96.68 %.