New promising agents against COPD and asthma among the amides of 1-oxo-3-phenyl-isochroman-6-carboxylic acid

Abstract

Background: Bronchodilators, which are compounds that can relax airway smooth muscle, are perhaps the most important component of combination therapy for chronic obstructive pulmonary disease, one of the most common non-communicable diseases in the world, which is the second most lethal disease after cardiovascular disease. Unfortunately, current clinical bronchodilators, whose activity is mediated by their interaction with muscarinic acetylcholine receptors, have side effects (up to myocardial infarction) due to their cross-affinity for different types of these receptors, including those prevalent in the heart muscle. Objectives: The aim of this work is to search/develop compounds — effective bronchodilators capable of selectively inhibiting type 3 muscarinic acetylcholine receptors (M3 receptors), predominantly present in smooth muscles and not characteristic of cardiomyocytes. Materials and Methods: High-throughput virtual screening of a collection of 150,000 compounds was conducted on the spatial structure of the M3 receptor, reconstructed in our previous studies. The effect of substances on contractile activity was investigated using tensometry in isometric mode on multicellular tracheal preparations. Antagonistic activity and type of inhibition were determined against the background of acetylcholine application (concentration range 10-10–10-3 M). To establish the affinity value of the compound-antagonist, the Schild regression equation was used. Results: Based on virtual screening data, a series of compounds — amides of 1-oxo-3-phenyl-iso-chroman-6-carboxylic acid — were selected for biological testing. For two of these compounds (Compounds 1 and 7), the ability to selectively inhibit M3 receptors was demonstrated. Specifically, the affinity value pKB for Compound 1 was 7.28 ± 0.70, with an IC50 of 5.25·10-8 M. A critically important advantage of this compound is its ability, at equal concentrations, to more effectively inhibit signal transmission through M3 receptors compared to ipratropium bromide — a clinical cholinergic receptor inhibitor. Conclusions: The sufficient effectiveness of inhibition and significantly increased selectivity of the studied compounds specifically towards M3 receptors provide strong grounds to consider these compounds as promising precursors of new generation cholinolytic drugs with targeted action on M3-type cholinergic receptors.