Identification of 3-acyl-2-phenylamino-1,4-dihydroquinolin-4-one derivatives as inhibitors of the phosphatase SerB653 in Porphyromonas gingivalis, implicated in periodontitis

The serine phosphatase SerB653 plays a crucial role in the infection of Porphyromonas gingivalis, which contributes to the pathogenesis of periodontitis, an inflammatory disease of teeth-supporting tissues. Because functional loss of SerB653 eliminates the virulence of P. gingivalis, SerB653 inhibitors are considered potential periodontitis therapeutic or preventive agents. To identify SerB653 inhibitors with potent anti-periodontitis activity, we conducted a high-throughput screen of a representative 6800-compound subset of a synthetic chemical library of the Korea Chemical Bank (KCB) for compounds with activity against SerB653. The primary screening yielded 150 hits, and subsequent confirmatory studies identified eight compounds, mainly within a single cluster of 3-acyl-2-phenylamino-1,4-dihydroquinolin-4-one derivatives, that showed greater than 50% inhibition of SerB653 activity at a concentration of 50 μM. A second screening with a focused library identified 10 compounds with IC50 values less than 10 μM. In antibacterial tests, three of these compounds showed a minimum inhibitory concentration against P. gingivalis growth of 5-50 nM.