Dichloro-4-quinolinol-3-carboxylic acid: Synthesis and antioxidant abilities to scavenge radicals and to protect methyl linoleate and DNA

Design, Synthesis, Anti-Proliferative Evaluation and Cell Cycle Analysis of Hybrid 2-Quinolones

Background:

Quinolones are a significant group of nitrogen heterocyclic compounds that exist in therapeutic agents, alkaloids, and synthetic small molecules that have important biological activities. A wide range of quinolones have been used as antituberculosis, antibacterial, anti-malarial, antifungal, anticonvulsant, anticancer agents and urease inhibitors.

Methods:

Ethyl 3,3-disubstituted-2-cyano propionates containing hybride quinolones derivatives were synthesized by the reaction of 1-amino-7-hydroxy-4-methylquinolin-2(1H)-one and its dibromo derivative with α, β-unsaturated carbonyl in ethanol.

Results:

A novel series of hybrid 2-quinolone derivatives was designed and synthesized. The compounds structures were confirmed using different spectroscopic methods and elemental analysis. The cytotoxic activities of all the compounds were assessed against HepG2 cell line in comparison with doxorubicin as a standard drug.

Conclusion:

Most compounds revealed superior anti-proliferative activity than the standard. Compound 4b, is the most active compound (IC50 = 0.39mM) compared with doxorubicin (IC50 = 9.23mM). DNA flow cytometric analysis of compound 4b showed cell cycle arrest at G2/M phase with a concomitant increase of cells in apoptotic phase. Dual annexin-V/ propidium iodide staining assay of compound 4b revealed that the selected candidate increased the apoptosis of HepG-2 cells more than control.

Synthesis and preliminary anti-inflammatory and anti-bacterial evaluation of some diflunisal aza-analogs

Our aim was to identify new multi-target compounds endowed with both anti-inflammatory and anti-bacterial activities for treatment of human infections. Diflunisal, a nonsteroidal anti-inflammatory agent, has recently been repurposed for its anti-virulence properties against methicillin-resistant Staphylococcus aureus. Effective synthesis of some aza-analogs of the anti-inflammatory drug diflunisal was carried out following the route involving key oxazole intermediates to obtain o- and m-hydroxypyridinecarboxylic acid derivatives. The newly synthesized diflunisal aza-analogs did not exhibit cytotoxic activity up to 80 μM and some of them exhibited anti-inflammatory activities, decreasing the levels of pro-inflammatory cytokines and prostaglandins induced by bacterial lipopolysaccharide in human primary macrophages. Ten of the diflunisal aza-analogs were found to have interesting antibacterial activity, sensitizing S. aureus, Streptococcus pyogenes, Enterococcus faecium, and Pseudomonas aeruginosa to the antibacterial effects of beta-lactam antibiotics and protein synthesis inhibitors.

Synthesis and biological evaluation of some 4-functionalized-pyrazoles as antimicrobial agents

1,3-Diaryl-4-formylpyrazoles 8 bearing benzenesulfonamide moiety at position-1 were synthesized as important intermediates following Vilsmeier-Haack strategy. Aldehyde moiety of 4-formylpyrazole was then converted into carboxylic acid 9, cyano 10 and carbothioamide 11 using established procedures. Out of these 4-functionalized pyrazoles, pyrazole-4-carboxylic acids 9 and carbothioamides 11 were evaluated for their in vitro antibacterial activity against four pathogenic bacterial strains namely, Staphylococcus aureus, Bacillus subtilis (Gram-positive), Escherichia coli, Pseudomonas aeruginosa (Gram-negative), and in vitro antifungal activity against two pathogenic fungal strains namely, Aspergillus niger and Aspergillus flavus. Three tested compounds, 9e, 11b and 11f exhibited moderate antibacterial activity against Gram-positive bacteria and 9g showed moderate antifungal activity against the tested fungi. However, none of the compounds showed any activity against Gram-negative bacteria.