Antioxidant and Antibacterial Effects of Pollen Extracts on Human Multidrug-Resistant Pathogenic Bacteria

The present work was designed to search the possible antibacterial effect of the ethanolic extract of pollens from six botanical origins, Punica granatum, Quercus ilex, Centaurium erythraea, Coriandrum sativum, Ruta graveolens, and Citrus aurantium, against multidrug pathogenic bacteria, Escherichia coli, Pseudomonas aeruginosa, Enterobacter cloacae, Acinetobacter baumannii, Klebsiella pneumoniae, and Staphylococcus aureus. The content of phenolic compounds, flavones, and flavonols was measured. The antioxidant activities were evaluated using four assays: total antioxidant capacity, DPPH, ABTS, and reducing power. Antibacterial activity was studied using the agar disk diffusion method, and the MIC and MBC were determined. Results obtained showed a positive correlation between the antioxidant content of pollen extracts and the antibacterial capacity, Punica granatum and Quercus ilex pollen extracts were the most efficient against Gram-positive and Gram-negative bacteria, and Centaurium erythraea, Coriandrum sativum, and Ruta graveolens had a moderate effect, while Citrus aurantium had no antibacterial effect. It is concluded that pollens can be a good source of bioactive molecules that exhibit potent antioxidant effects and strong antibacterial activities.