Discovery of New Hydrazonothiazolines as Bovine and HumanCarbonic Anhydrase-II Inhibitors: In-vitro, Kinetics, Selectivity andMolecular Dynamics Exploration

Introduction: Carbonic Anhydrase II (CA-II) is crucial for several physiopathological processes, including bone calcification, osteoporosis, tumorigenicity, and epilepsy, among others. Usually, the intraocular pressure observed in glaucoma exacerbates the condition, and CA-II inhibitors have the potential to be used for the reduction of this pressure. Methods: Moreover, to search for novel CA-II inhibitors with high potency, a series of hydrazonothiazoline derivatives (5a-q) were synthesized. The inhibitory potency of our synthesized compounds was investigated for human and bovine CA-II through in-vitro and computational methods. The in vitro screening revealed that 5a-5f, 5g, 5h, and 5l have significant inhibitory action for bCA-II (IC50 = 13.1 μM to 44.6 μM), whereas 5a, 5d, 5f, 5h, and 5l exhibited excellent inhibition of hCA-II (IC50 = 7.0 μM to 33.1 μM). Therefore, binding pattern of those active hits was elucidated by in silico docking, which reflects that the thiazole group of ligands is responsible for binding of compounds with the target proteins and consequent functional inhibition of the enzyme. Moreover, the type of inhibition of active hits (5a and 5h for hCA-II and bCA-II, respectively) was explored by kinetics experiment in which both 5a (for hCA-II, Ki = 5.25±0.004 μM) and 5h (for bCA-II, Ki = 5.5±0.001 μM) competitively inhibited CA-II. Results: The molecular dynamics simulation, MMPBSA analysis, revealed that 5a has better stability in 1BN1 than 5h in 1V9E. Conclusion: Those identified inhibitors could serve as a skeleton to design more potent CA-II inhibitors in the future.