Development and Evaluation of Bis-benzothiazoles as a New Class of Benzothiazoles Targeting DprE1 as Antitubercular Agents.

Benzothiazole-bearing compounds have emerged as potential noncovalent DprE1 (decaprenylphosphoryl-ß-d-ribose-2'-epimerase) inhibitors active against Mycobacterium tuberculosis. Based on structure-based virtual screening (PDB ID: 4KW5), a focused library of thirty-one skeletally diverse benzothiazole amides was prepared, and the compounds were assessed for their antitubercular activity against M.tb H37Ra. Most potent compounds 3b and 3n were further evaluated against the M.tb H37Rv strain by the microdilution assay method. Among the compounds evaluated, bis-benzothiazole amide 3n emerged as a hit molecule and demonstrated promising antitubercular activity with minimum inhibitory concentration (MIC) values of 0.45 µg/mL and 8.0 µg/mL against H37Ra and H37Rv, respectively. Based on the preliminary hit molecule (3n), a focused library of 12 more bis-benzothiazole amide derivatives was further prepared by varying the substituents on either side to obtain new leads and generate a structure-activity relationship (SAR). Among these compounds, 6a, 6c, and 6d demonstrated remarkable antitubercular activity with MIC values of 0.5 µg/mL against H37Ra and 1.0, 2.0, and 8.0 µg/mL against H37Rv, respectively. The most active compound, 6a, also displayed significant efficacy against four drug-resistant tuberculosis strains. Compound 6a was assessed for in vitro cytotoxicity against the HepG2 cell line, and it displayed insignificant cytotoxicity. Furthermore, time-kill kinetic studies demonstrated time- and dose-dependent bactericidal activity of this compound. The GFP release assay revealed that compound 6a targets the inhibition of a cell wall component. SNPs in dprE-1 gene assessment revealed that compound 6a binds to tyrosine at position 314 of DprE1 and replaces it with histidine, causing resistance similar to that of standard TCA1. In silico docking studies further suggest that the strong noncovalent interactions of these compounds may lead to the development of potent noncovalent DprE1 inhibitors.

P-glycoprotein inhibitors as an adjunct therapy for TB.

The primary challenge in TB treatment is the emergence of multidrug-resistant TB (MDR-TB). One of the major factors responsible for MDR is the upregulation of efflux pumps. Permeation-glycoprotein (P-gp), an efflux pump, hinders the bioavailability of the administered drugs inside the infected cells. Simultaneously, angiogenesis, the formation of new blood vessels, contributes to drug delivery complexities. TB infection triggers a cascade of events that upregulates the expression of angiogenic factors and P-gp. The combined action of P-gp and angiogenesis foster the emergence of MDR-TB. Understanding these mechanisms is pivotal for developing targeted interventions to overcome MDR in TB. P-gp inhibitors, such as verapamil, and anti-angiogenic drugs, including bevacizumab, have shown improvement in TB drug delivery to granuloma. In this review, we discuss the potential of P-gp inhibitors as an adjunct therapy to shorten TB treatment.

Chitosan functionalized PCL nanoparticles bearing tyrosine kinase inhibitor osimertinib mesylate for effective lung cancer therapy.

Lung cancer ranks second position among the cancer-related deaths. Osimertinib mesylate (OSM) is a tyrosine-kinase-inhibitor which can effectively treat non-small cell lung cancer (NSCLC), but still there are certain limitations and side effects which could be circumvented by polymeric nanoparticles approach. Hence, this research was aimed to develop drug-loaded biodegradable polycaprolactone nanoparticles (PCL-NPs) such as OSM-loaded PCL-NPs (PCL-OSM-NPs) and chitosan fabricated OSM-loaded PCL-NPs (CS-PCL-OSM-NPs) to achieve active-targeting of OSM in the cancerous lung tissue. Thus, CS-PCL-OSM-NPs enhance the anticancer efficacy due to active targeting nature and thereby reduces off-target side effects of OSM in the NSCLC treatment. Blank PCL-NPs, PCL-OSM-NPs, and CS-PCL-OSM-NPs were prepared by nanoprecipitation method. Optimized blank PCL-NPs, PCL-OSM-NPs, and CS-PCL-OSM-NPs exhibited the mean particle size of 90.2 ± 4.7 nm, 167.7 ± 2.9 nm, and 233.7 ± 4.8 nm respectively. The encapsulation efficiency % (%EE) of PCL-OSM-NPs was found to be 68.4 ± 3.2%. In vitro drug release study demonstrated sustained release profile of 69.5 ± 5% and 65.7 ± 1.5% for OSM from both the PCL-OSM-NPs and CS-PCL-OSM-NPs, respectively. The PCL-OSM-NPs and CS-PCL-OSM-NPs demonstrated the inhibition of 82.2 ± 0.5% and 81.9 ± 0.2% in A549 cancer cells respectively which clearly signified the improved efficacy. Moreover, the PCL-OSM-NPs and CS-PCL-OSM-NPs exhibited significantly less hemolysis than OSM indicating safety of the formulation. These findings indicate that biohemocompatible CS-PCL-OSM-NPs is an attractive option to treat NSCLC with enhanced anticancer activity and reduced side effects.