Discovery of novel 2',3',4'-trihydroxy-2-phenylacetophenone derivatives as anti-gram-positive antibacterial agents.

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 LC(50) of 5.8 muM and 5.6 muM 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.