Antimicrobial Efficacy of Metal-Barbiturate Conjugates Against Pathogenic Strains of Escherichia coli and Staphylococcus aureus

Coupling Microplate-Based Antibacterial Assay with Liquid Chromatography for High-Resolution Growth Inhibition Profiling of Crude Extracts: Validation and Proof-of-Concept Study with Staphylococcus aureus

With the identification of novel antibiotics from nature being pivotal in the fight against human pathogenic bacteria, there is an urgent need for effective methodologies for expedited screening of crude extracts. Here we report the development and validation of a simple and dye-free antimicrobial assay in 96-well microplate format, for both determination of IC₅₀ values and high-resolution inhibition profiling to allow pin-pointing of bioactive constituents directly from crude extracts. While commonly used antimicrobial assays visualize cell viability using dyes, the developed and validated assay conveniently uses OD₆₀₀ measurements directly on the fermentation broth. The assay was validated with an investigation of the inhibitory activity of DMSO against Staphylococcus aureus, temperature robustness, interference by coloured crude extracts as well as inter-day reproducibility. The potential for high-resolution S. aureus growth inhibition profiling was evaluated on a crude extract of an inactive Alternaria sp., spiked with ciprofloxacin.

F. A review on the development of urease inhibitors as antimicrobial agents against pathogenic bacteria

Ureases are enzymes that hydrolyze urea into ammonium and carbon dioxide. They have received considerable attention due to their impacts on living organism health, since the urease activity in microorganisms, particularly in bacteria, are potential causes and/or factors contributing to the persistence of some pathogen infections. This review compiles examples of the most potent antiurease organic substances. Emphasis was given to systematic screening studies on the inhibitory activity of rationally designed series of compounds with the corresponding SAR considerations. Ureases of Canavalia ensiformis, the usual model in antiureolytic studies, are emphasized. Although the active site of this class of hydrolases is conserved among bacteria and vegetal ureases, the same is not observerd for allosteric site. Therefore, inhibitors acting by participating in interactions with the allosteric site are more susceptible to a potential lack of association among their inhibitory profile for different ureases. The information about the inhibitory activity of different classes of compounds can be usefull to guide the development of new urease inhibitors that may be used in future in small molecular therapy against pathogenic bacteria.

Synthesis of a gemini quaternary ammonium salt and its reaction with wool fabric using click chemistry

In this study, we have successfully synthesized a gemini quaternary ammonium salt C₂₄H₃₈O₄N₂Br₂ and applied it to wool fabric to obtain antibacterial properties.

New barbiturates and thiobarbiturates as potential enzyme inhibitors

A series of 27 new barbiturates and thiobarbiturates have been synthesized by a convenient multi-component reaction in overall excellent yields (87-96%). All the synthesized compounds were characterized by 1H, 13C NMR, EIMS and elemental analysis (C, H, N and S). Furthermore, all compounds were screened for in vitro antioxidant (DPPH radical scavenging), lipoxygenase, chymotrypsin, α-glucosidase and anti-urease activities. Out of the series, 23 in DPPH, 14 in lipoxygenase, 2 in chymotrypsin have shown appreciable IC50 values.