Antimicrobial activity of phenol and benzoic acid derivatives

Vinyl monomers with phenol and benzoic acid as pendant groups were synthesized, and their antimicrobial activities were examined on equal weight basis using the halo zone test. For both bacteria and fungi, the halo zone diameter decreased in the order of p-hydroxyphenyl acrylate (M2)>allyl p-hydroxyphenyl acetate (M1)≈p-2-propenoxyphenol (M3). Polymerization of the monomers decreased their antimicrobial activity significantly, but the order of the halo zone diameter for the polymers was the same as that of the corresponding monomers. Glassy polymers exhibited low antimicrobial activity when compounded with low molecular weight antimicrobial agents due to the extremely slow diffusion. Antimicrobial polymers could find a successful application such as coating on glassy polymers, in spite of the lower antimicrobial activity compared to the respective monomers.