Bioevaluation of quinoline-4-carbonyl derivatives of piperazinyl-benzothiazinones as promising antimycobacterial agents

New 7-hydroxycoumarin acetamide derivatives as human carbonic anhydrase IX and XII inhibitors: Design, synthesis, biological evaluation and molecular docking studies

Carbonic anhydrases (CAs) are crucial in regulating various physiological processes in the body. The overexpression of isoforms human carbonic anhydrases (hCA) IX and hCA XII is linked to tumour progression. The selective inhibition of CA IX and CA XII isoforms can result in the development of better cancer treatment strategies. The tail approach based on coumarin derivatives was known for selective inhibition of isoforms IX and XII. This study explores the potential of coumarin derivatives (7a-k, 8a-s and 9a-g) as selective hCA IX and hCA XII inhibitors. The synthesised derivatives exhibited potent and selective inhibition towards hCA IX and XII, with Ki values in the range of 0.58‒3.33 µM and 0.48‒2.59 µM, respectively. The oxime ether derivative 7d was found to be the most potent one against hCA IX, with a Ki value of 0.58 µM, and phenyl hydrazine derivative 8a, with a Ki value of 0.48 µM against hCA XII, was the most potent one among the synthesised molecules. The potent isoform-specific carbonic anhydrase IX and XII inhibition suggests that 7d and 8a can be taken further towards the development of potent anticancer agents.

Recent Advancements in Benzothiazinones (BTZ) Analogs as DprE1 Inhibitor for Potent Antitubercular Therapeutics

Benzothiazinone analogs have emerged as a promising class of compounds having potent antimycobacterial activity, particularly against Mycobacterium tuberculosis, the pathogen responsible for tuberculosis. This review highlights the development of benzothiazinone analogs as potential antitubercular agents from the beginning to the recent advancement in the past decade. These compounds have shown potent activity, including drug‐resistant strains of Mycobacterium tuberculosis. Structure–activity relationship studies and modifications have improved their efficacy. Benzothiazinone analogs have favorable pharmacokinetic profiles and show promise in preclinical studies. Challenges include addressing resistance mechanisms and ensuring safety. Their unique mode of action and promising properties make them attractive candidates for the battle against drug‐resistant tuberculosis.

Structure-activity relationship mediated molecular insights of DprE1 inhibitors: A Comprehensive Review

Emerging threats of multi-drug resistant (MDR), extensively drug-resistant (XDR), and totally drug-resistant (TDR) tuberculosis led to the discovery of a novel target which was entitled Decaprenylphosphoryl-β-D-ribose 2'-epimerase (DprE1) enzyme. DprE1 is composed of two isoforms, decaprenylphosphoryl-β-D-ribose oxidase (DprE1) and decaprenylphosphoryl-D-2-keto erythro pentose reductase (DprE2). The enzymes, DprE1 and DprE2, regulate the two-step epimerization process to form DPA (Decaprenylphosphoryl arabinose) from DPX (Decaprenylphosphoryl-D-ribose), which is the sole precursor in the cell wall synthesis of arabinogalactan (AG) and lipoarabinomannan (LAM). Target-based and whole-cell-based screening played an imperative role in the identification of the druggable target, DprE1, whereas the druggability of the DprE2 enzyme is not proved yet. To date, diverse scaffolds of heterocyclic and aromatic ring systems have been reported as DprE1 inhibitors based on their interaction mode, i.e. covalent, and non-covalent inhibitors. This review describes the structure-activity relationship (SAR) of reported covalent and non-covalent inhibitors to enlighten about the crucial pharmacophoric features required for DprE1 inhibition, along with in-silico studies which characterize the amino acid residues responsible for covalent and non-covalent interactions.Communicated by Ramaswamy H. Sarma.

Novel strategies based on natural products and synthetic derivatives to overcome resistance in Mycobacterium tuberculosis

One of the biggest health challenges of today's world is the emergence of antimicrobial resistance (AMR), which renders conventional therapeutics insufficient and urgently demands the generation of novel antimicrobial strategies. Mycobacterium tuberculosis (M. tuberculosis), the pathogen causing tuberculosis (TB), is among the most successful bacteria producing drug-resistant infections. The versatility of M. tuberculosis allows it to evade traditional anti-TB agents through various acquired and intrinsic mechanisms, rendering TB among the leading causes of infectious disease-related mortality. In this context, researchers worldwide focused on establishing novel approaches to address drug resistance in M. tuberculosis, developing diverse alternative treatments with varying effectiveness and in different testing phases. Overviewing the current progress, this paper aims to briefly present the mechanisms involved in M. tuberculosis drug-resistance, further reviewing in more detail the under-development antibiotics, nanotechnological approaches, and natural therapeutic solutions that promise to overcome current treatment limitations.

Design and synthesis of benzofuran- and naphthalene-fused thiazinones as antimycobacterial agents

Benzothiazinones (BTZs) have widely inspired medicinal chemistry and translational research due to their remarkable antitubercular potency and clinical potential. While most structure-activity relationship campaigns have largely focused on lateral chain modifications and substituents on the BTZ core, scaffold hopping strategies have been rarely investigated previously. In this work, we report the first example of ring expansion of the BTZ core toward benzofuran- and naphthalene-fused thiazinones. In vitro testing showed micromolar activity for both compounds, and molecular docking simulations provided insights into their reduced inhibitory capacity toward the enzymatic target (DprE1). Calculated electrochemical potentials revealed a lower susceptibility to reduction as opposed to BTZ drug candidates, in line with the mechanistic requirement for covalent binding.

Comprehensive coverage on anti-mycobacterial endeavour reported during 2022

TB being one of the deadliest diseases and second most common infectious cause of deaths, poses the severe threat to global health. The extended duration of therapy owing to resistance and its upsurge in immune-compromised patients have been the driving force for the development of novel of anti-TB scaffolds. Recently, we have compiled the account of anti-mycobacterial scaffolds published during 2015-2020 and updated them in 2021. The present work involves the insights on the anti-mycobacterial scaffolds reported in 2022 with their mechanism of action, structure activity relationships, along with the key perceptions for the design of newer anti-TB agents for the broader interests of medicinal chemists.