Discovery of Novel 2′,3′,4′-Trihydroxy-2-phenylacetophenone Derivatives as Anti-Gram-Positive Antibacterial Agents

Abstract

A number of 2′,3′,4′-trihydroxy-2-phenylacetophenone derivatives were synthesized and examined for growth inhibition of several kinds of bacteria. 2′,3′,4′-Trihydroxy-2-phenylacetophenone itself exhibited no antibacterial activity, but some of its derivatives showed various antibacterial activities depending on functional groups introduced on the 2-phenyl ring. Eighteen out of 24 compounds synthesized in this study appeared to possess antibacterial activities against at least two Gram-positive strains of Bacillus subtilis and Staphylococcus aureus, 2-(biphenyl-4-yl)-2′,3′,4′-trihydroxyacetophenone being the most active with LC₅₀ of 5.8 μM and 5.6 μM respectively. However, none of the synthesized compounds exhibited inhibitory effects on Gram-negative strains, such as Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, and Salmonella enterica, suggesting that anti-Gram-positive specificity of the antibacterial compounds.