Synthesis and evaluation of some novel precursors of oxazolidinone analogues of chloroquinoline for their antimicrobial and cytotoxic potential

Current Landscape and Future Perspective of Oxazolidinone Scaffolds Containing Antibacterial Drugs

The widespread use of antibiotics has made the problem of bacterial resistance increasingly serious, and the study of new drug-resistant bacteria has become the main direction of antibacterial drug research. Among antibiotics, the fully synthetic oxazolidinone antibacterial drugs linezolid and tedizolid have been successfully marketed and have achieved good clinical treatment effects. Oxazolidinone antibacterial drugs have good pharmacokinetic and pharmacodynamic characteristics and unique antibacterial mechanisms, and resistant bacteria are sensitive to them. This Perspective focuses on reviewing oxazolidinones based on the structural modification of linezolid and new potential oxazolidinone drugs in the past 10 years, mainly describing their structure, antibacterial activity, safety, druggability, and so on, and discusses their structure-activity relationships, providing insight into the reasonable design of safer and more potent oxazolidinone antibacterial drugs.

The Current Status of O-Heterocycles: A Synthetic and Medicinal Overview

O-Heterocycles have been explored in the field of medicinal chemistry for a long time, but their significance has not been duly recognised and they are often shunned in favour of N-heterocycles. The design of bioactive molecules for nearly every pathophysiological condition is primarily focused on novel N-heterocycles. The main reasons for such bias include the ease of synthesis and possible mimicking of physiological molecules by N-heterocycles. But considering only this criterion rarely provides breakthrough molecules for a given disease condition, and instead the risks of toxicity or side effects are increased with such molecules. On the other hand, owing to improved synthetic feasibility, O-heterocycles have established themselves as equally potent lead molecules for a wide range of pathophysiological conditions. In the last decade there have been hundreds of reports validating the fact that equally potent molecules can be designed and developed by using O-heterocycles, and these are also expected to have comparably low toxicity. Even so, researchers tend to remain biased toward the use of N-heterocycles over O-heterocycles. Thus, this review provides a critical analysis of the synthesis and medicinal attributes of O-heterocycles, such as pyrones, oxazolones, furanones, oxetanes, oxazolidinones, and dioxolonones, and others, reported in the last five years, underlining the need for and the advantages guiding researchers toward them.

Antiproliferative activity of a series of 5‑(1H‑1,2,3‑triazolyl) methyl‑ and 5‑acetamidomethyl‑oxazolidinone derivatives

In the face of increasing resistance to the existing antibiotics, oxazolidinones (exemplified by linezolid) have been developed as promising antibacterial agents, but may have other useful actions. In the present study, a series of 5‑(1H‑1,2,3‑triazoly) l‑methyl‑, 5‑acetamidomethyl‑morpholino and N‑substituted‑piperazino oxazolidinone derivatives were investigated to determine whether they are active against eukaryotic cells. An MTT assay, validated by cell counting, was used to assess the effect of nine oxazolidinone derivatives (concentrations 100 nM‑10 µM) on the proliferation of MCF7 human breast cancer cells. The three most active compounds were then tested on MDA231 breast cancer cells. Cytotoxicity of the selected derivatives was determined by assessing the extent of apoptosis by flow cytometry. The antimetastatic potential of these compounds was assessed on MDA231 cells using wound healing and agarose invasion assays. The 5‑triazolylmethyl piperazino‑oxazolidinone derivatives containing 4‑N‑(2‑chlorocinnamoyl), 4‑N‑(4‑nitrobenzoyl) and 4‑N‑methylsulfonyl moieties exhibited the most potent cytostatic activity against cancer, inhibiting proliferation by up to 70%, in the same order as their reported antibacterial activity against Staphylococcus aureus, but at higher concentrations. Unexpectedly, several derivatives stimulated proliferation at 100 nM, well below their antibacterial minimum inhibitory concentrations. Certain compounds also retarded the motility and invasion of MDA231 cells. Three of the tested derivatives had no effect on the eukaryotic cell lines, demonstrating their preferential activity against bacteria. Two compounds actually stimulated eukaryotic cell proliferation. The remaining three exhibited potent cytostatic activity against and cancer cells, displaying differences in response at low and high concentrations, which may suggest multiple targets on eukaryotic cells. These latter compounds may be useful as anticancer agents.