Design and synthesis of novel antimicrobials with activity against Gram-positive bacteria and mycobacterial species, including M. tuberculosis

Advances in antibacterial agents for Mycobacterium fortuitum

Mycobacterium fortuitum is an emerging human pathogen, characterized by an increase in prevalence and antibacterial resistance over the years, highlighting the need for the development of new drugs against this rapidly growing nontuberculous mycobacterium (NTM). To support this crusade, this review summarizes findings from the past two decades concerning compounds with antimycobacterial activity against M. fortuitum. It identifies the most promising and effective chemical frameworks to inspire the development of new therapeutic alternatives for infections caused by this microorganism. Most compounds effective against M. fortuitum are synthetic, with macozinone, featuring a 2-piperazine-benzothiazinone framework, standing out as a notable drug candidate. Among natural products, the polyphenolic polyketide clostrubin and the sansanmycin peptide analogs have shown efficacy against this NTM. Some compounds' mechanisms of action on M. fortuitum have been studied, including NITD-916, which acts as an enoyl-acyl carrier protein reductase inhibitor, and TBAJ-5307, which inhibits F-ATP synthase. Moreover, this review discusses the pathogenic molecular mechanisms and potential therapeutic targets within this mycobacterium.

A consensus reverse docking approach for identification of a competitive inhibitor of acetyltransferase enhanced intracellular survival protein from Mycobacterium tuberculosis

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (Mtb), which remains a significant global health challenge. The emergence of multidrug-resistant (MDR) Mtb strains imposes the development of new therapeutic strategies. This study focuses on the identification and evaluation of potential inhibitors against Mtb H37Ra through a comprehensive screening of an in-house chemolibrary. Subsequently, a promising pyrimidine derivative (LQM495) was identified as promising and then further investigated by experimental and in silico approaches. In this context, computational techniques were used to elucidate the potential molecular target underlying the inhibitory action of LQM495. Then, a consensus reverse docking (CRD) protocol was used to investigate the interactions between this compound and several Mtb targets. Out of 98 Mtb targets investigated, the enhanced intracellular survival (Eis) protein emerged as a target for LQM495. To gain insights into the stability of the LQM495-Eis complex, molecular dynamics (MD) simulations were conducted over a 400 ns trajectory. Further insights into its binding modes within the Eis binding site were obtained through a Quantum mechanics (QM) approach, using density functional theory (DFT), with B3LYP/D3 basis set. These calculations shed light on the electronic properties and reactivity of LQM495. Subsequently, inhibition assays and kinetic studies of the Eis activity were used to investigate the activity of LQM495. Then, an IC50 value of 11.0 ± 1.4 µM was found for LQM495 upon Eis protein. Additionally, its Vmax, Km, and Ki parameters indicated that it is a competitive inhibitor. Lastly, this study presents LQM495 as a promising inhibitor of Mtb Eis protein, which could be further explored for developing novel anti-TB drugs in the future.

Metal-free annulative hydrosulfonation of propiolate esters: synthesis of 4-sulfonates of coumarins and butenolides

An efficient metal-free and cost-effective method for the synthesis of coumarin and butenolide 4-sulfonates has been developed involving addition of sulfonic acids to ethyl propiolates followed by lactonization.

A Catalytic Cross-Olefination of Diazo Compounds with Sulfoxonium Ylides

A ruthenium‐catalysed cross‐olefination of diazo compounds and sulfoxonium ylides is presented. Our reaction design exploits the intrinsic difference in reactivity of diazo compounds and sulfoxonium ylides as both carbene precursors and nucleophiles, which results in a highly selective reaction.

Base-promoted isomerization of CF3-containing allylic alcohols to the corresponding saturated ketones under metal-free conditions

Following to the computational expectation, our previously reported intriguing 1,3-proton shift of 4,4,4-trifluorobut-2-yn-1-ols was successfully extended to the 4,4,4-trifluorobut-2-en-1-ol system under metal-free conditions to afford the corresponding saturated ketones in high to excellent chemical yields using such a convenient and easy-to-handle base as DBU at the toluene refluxing temperature, and utilization of the corresponding optically active substrates unambiguously demonstrated that this transformation proceeded in a highly stereoselective fashion.

Development and Characterization of Nanoembedded Microparticles for Pulmonary Delivery of Antitubercular Drugs against Experimental Tuberculosis

The foremost objective of the present research study was to develop and evaluate the potential of rifampicin (RIF) and isoniazid (INH) loaded spray dried nanoembedded microparticles against experimental tuberculosis (TB). In this study, RIF-INH loaded various formulations (chitosan, guar gum, mannan, and guar gum coated chitosan) were prepared by spray drying and characterized on the basis of in vitro as well as in vivo studies. Results showed that guar gum spray dried particles showed uniform size distribution with smooth surface as compare to mannan formulations. Guar gum batches exhibited excellent flow ability attributed to their optimum moisture content and uniform size distribution. The drug release showed the biphasic pattern of release, i.e., initial burst followed by a sustained release pattern. The preferential uptake of guar gum coated formulations suggested the presence and selective uptake capability of mannose moiety to the specific cell surface of macrophages. In vivo lung distribution study showed that guar gum coated chitosan (GCNP) batches demonstrated prolonged residence at the target site and thereby improve the therapeutic utility of drug with a significant reduction in systemic toxicity. Optimized drug loaded GCNP formulation has resulted in almost 5-fold reduction of the number of bacilli as compared to control group. Histopathology study also demonstrated that none of the treated groups show any evidence of lung tissue abnormality. Hence, GCNPs could be a promising carrier for selective delivery of antitubercular drugs to alveolar macrophages with the interception of minimal side effects, for efficient management of TB.