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

Abstract

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.

The Influence of Enzymatic Hydrolysis on Bee Pollen Antioxidant and Antibacterial Activities

“…The observed trend, characterized by high correlation coefficient values for tested characteristics (see Section 3.5), suggested that the composition and quantity of biologically active compounds have a significant impact on the antibacterial activity of bee pollen. This relationship between the high levels of bioactive compounds, antioxidant content, and AA has also been analyzed and confirmed by other studies [30][31][32][33][34][35].…”

“…Similarly, other studies have also analyzed and successfully demonstrated the more effective AA of bee pollen extracts against Gram-positive bacteria cultures. Velasueze et al [31] and Bakour et al [34] evaluated the antibacterial impact of bee pollen on S. aureus, E. coli, and P. aeruginosa and both studies reported higher activity of the extracts against Gram-positive bacteria strains.…”

Holm Oak (Quercus ilex subsp. ballota (Desf.) Samp.) Bark Aqueous Ammonia Extract for the Control of Invasive Forest Pathogens

“…Knapp) Kurtzman and Zygosacharomyces bailii (Lindner) Guillierm at a concentration of 2000 µg·mL −1 , attributed to the high content of phenolic compounds; Sánchez-Gutiérrez et al [ 24 ] demonstrated the antibacterial activity of an aqueous extract of Q. ilex leaves obtained by a microwave-assisted extraction procedure against foodborne Gram- and Gram+ bacteria with inhibition values in the 1000 to 5000 µg·mL −1 range; and Güllüce et al [ 25 ] tested in vitro a methanol extract of Q. ilex leaves against a wide range of human and plant-associated microorganisms, including Pseudomonas syringae Van Hall 1904, with a MIC of 250 µg·mL −1 . Berahou et al [ 10 ] tested different solvents (ethyl acetate, n -butanol, or water) to prepare Q. ilex bark extracts, and assayed them against 11 reference bacterial strains, finding inhibition values ranging from 128 to 512 μg·mL −1 ; Merghache et al [ 26 ] showed the inhibitory capacity of Q. ilex wood ashes against Candida albicans at a 5% concentration; and Bakour et al [ 27 ] studied the antibacterial effect of the ethanolic extract of pollen from six botanicals, including Q. ilex , finding that it was the most efficient against multidrug-resistant bacteria.…”

Bee Bread as a Promising Source of Bioactive Molecules and Functional Properties: An Up-To-Date Review

“…In most studies, it seems that Gram-positive bacteria are, in general, more susceptible to bee bread extract than Gram-negative bacteria. This may be due to the cytoplasmic membrane of Gram-negative bacteria, which contains less anionic phospholipids than Gram-positive bacteria; this particular composition is the cause of the resistance of certain Gram-negative bacteria to antibiotics [ 89 ].…”