Characterization of 8-hydroxyquinoline derivatives containing aminobenzothiazole as inhibitors of dengue virus type 2 protease in vitro

Four serotypes of dengue virus (DENV1-4), mosquito-borne members of Flaviviridae family cause frequent epidemics causing considerable morbidity and mortality in humans throughout tropical regions of the world. There is no vaccine or antiviral therapeutics available for human use. In a previous study, we reported that compounds containing the 8-hydroxyquinoline (8-HQ) scaffold as inhibitors of West Nile virus serine protease. In this study, we analyzed potencies of some compounds with (8-HQ)-aminobenzothiazole derivatives for inhibition of DENV2 protease in vitro. We identified analogs 1-4 with 2-aminothiazole or 2-aminobenzothiazole scaffold with sub-micromolar potencies (IC50) in the in vitro protease assays. The kinetic constant (K-i) for the most potent 8-HQ-aminobenzothiazole inhibitor (compound 1) with an IC50 value of 0.91 +/- 0.05 mu M was determined to be 2.36 +/- 0.13 mu M. This compound inhibits the DENV2 NS2B/NS3pro by a competitive mode of inhibition. (C) 2012 Elsevier B.V. All rights reserved.