1. Academic Validation
  2. Structure-Based Optimization of Coumestan Derivatives as Polyketide Synthase 13-Thioesterase(Pks13-TE) Inhibitors with Improved hERG Profiles for Mycobacterium tuberculosis Treatment

Structure-Based Optimization of Coumestan Derivatives as Polyketide Synthase 13-Thioesterase(Pks13-TE) Inhibitors with Improved hERG Profiles for Mycobacterium tuberculosis Treatment

  • J Med Chem. 2022 Oct 13;65(19):13240-13252. doi: 10.1021/acs.jmedchem.2c01064.
Wei Zhang 1 Shichun Lun 2 Shuang-Shuang Wang 1 Yan-Peng Cai 1 Fan Yang 1 Jie Tang 3 William R Bishai 2 Li-Fang Yu 1
Affiliations

Affiliations

  • 1 Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, China.
  • 2 Center for Tuberculosis Research, Department of Medicine, Division of Infectious Disease, Johns Hopkins School of Medicine, Baltimore, Maryland 21231-1044, United States.
  • 3 Shanghai Key Laboratory of Green Chemistry and Chemical Process, School of Chemistry and Molecular Engineering, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, China.
Abstract

Pks13 was identified as a key Enzyme involved in the final step of mycolic acid biosynthesis. We previously identified antitubercular coumestans that targeted Pks13-TE, and these compounds exhibited high potency both in vitro and in vivo. However, lead compound 8 presented potential safety concerns because it inhibits the hERG Potassium Channel in electrophysiology patch-clamp assays (IC50 = 0.52 μM). By comparing the Pks13-TE-compound 8 complex and the ligand-binding pocket of the hERG ion channel, fluoro-substituted and oxazine-containing coumestans were designed and synthesized. Fluoro-substituted compound 23 and oxazine-containing coumestan 32 showed excellent antitubercular activity against both drug-susceptible and drug-resistant Mtb strains (MIC = 0.0039-0.0078 μg/mL) and exhibited limited hERG inhibition (IC50 ≥ 25 μM). Moreover, 32 exhibited improved metabolic stability relative to parent compound 8 while showing favorable bioavailability in mouse models via serum inhibition titration assays.

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