Egyptian propolis 14: Potential antibacterial activity of propolis-encapsulated alginate nanoparticles against different pathogenic bacteria strains

A G Hegazi, A S El-Houssiny and E A Fouad

Abstract

The present study evaluates the synergistic antimicrobial effect of the propolis-encapsulated alginate nanoparticles (propolis-ALg NPs) against different pathogenic bacteria. The prepared samples were characterised by transimissin electron microscope (TEM), Fourier-transform infrared spectroscopy (FTIR), zeta potential and dielectric spectroscopy. The morphological analysis using TEM revealed that, the propolis-ALg NPs are spherical, discrete and have a small particle size (13 nm) in the nanometer scale. FTIR studies showed a spectral change of the characteristic absorption bands of ALg NPs after being encapsulated with propolis. A high negative zeta potential value is obtained for propolis-ALg NPs which indicates a high suspension stability of the prepared formulation. The dielectric study showed a decrease in the dielectric constant ( ε′), dielectric loss ( ε″) and conductivity ( σ) values after the incorporation of the propolis into ALg NPs. All these investigations confirm the successful encapsulation of propolis within ALg NPs. On the other hand, the propolis-ALg NPs sample showed the highest antimicrobial activity against all examined pathogens in comparison with pure propolis and/or antibiotic (clindamycin). So, it can be concluded that the propolis-ALg NPs exhibited a synergistic antibacterial activity against different bacterial strains.