Anti-quorum sensing activity in Pseudomonas aeruginosa PA01 of benzimidazolium salts: electronic, spectral and structural investigations as theoretical approach

Design, spectroscopic characterization, in silico and in vitro cytotoxic activity assessment of newly synthesized thymol Schiff base derivatives

Cancer is a global public health problem affecting millions of people every year. New anticancer drug candidates are needed to overcome the resistance to drugs used in the treatment of various types of cancer. In this study, two new series of benzenesulfonate-based thymol derivatives (14-19 and 20-25) were synthesized for the first time as promising chemotherapeutic agents and characterized using FT-IR, 1D NMR (1H- and 13C-NMR, APT, DEPT 135), 2D NMR (HETCOR and HMBC), and elemental analysis (CHNS). Antiproliferative activity of the molecules was determined against cancer cell lines, namely, the human lung adenocarcinoma cell line (A549) and the colorectal adenocarcinoma cell line (DLD-1), using MTT method for both 48 and 72 h. Compounds (14-25) showed cytotoxic activities against A549 with IC50 values ranging from 9.98 to 81.83 μM, respectively, compared to cisplatin (6.65 μM). These compounds exhibited antiproliferative activities against DLD-1 cancer cells at concentrations ranging from 4.29 to 53.62 μM, respectively, compared to cisplatin (9.91 μM). Especially, compound 16 displayed significant cytotoxicity on A549 and DLD-1 cancer cells with IC50 values of 9.98 and 10.75 μM, respectively. Finally, molecular docking studies were performed with Bcl-2, VEGFR-2, EGFR, and HER2 targets using the Schrödinger 2021-2 Maestro Glide program. The binding energy values and binding interactions of compounds 16 and 22 were determined to be the result of their interactions with these targets. Schrödinger 2021-2 Qikprop wizard drug similarity ratios and ADME prediction of all compounds 14-25 were also calculated.Communicated by Ramaswamy H. Sarma.

Vanadium(IV) complexes of salicylaldehyde-based furoic acid hydrazones: Synthesis, BSA binding and in vivo antidiabetic potential

Solution synthesis afforded five novel neutral heteroleptic octahedral paramagnetic mononuclear oxidovanadium(IV) complexes of general composition [VO(bpy)L], where L is a dianionic tridentate ONO-donor hydrazone ligand derived from 2-furoic acid hydrazide and salicylaldehyde and its 5-substituted derivatives. Characterization was carried out by elemental analysis, mass spectrometry, infrared, electron, NMR, and EPR spectroscopy, cyclic voltammetry and conductometry. The molecular and crystal structure of the complex with 5-chloro-salicylaldehyde 2-furoic acid hydrazone (2) was determined. The quantum chemical properties of the vanadium complexes were studied at B3LYP and M062X levels with the lanl2dz basis set using Gaussian. Additionally, Swiss-ADME analysis was performed and complex (4), featuring a 5-nitro substituent on the hydrazone ligand, was selected for further investigation. The effects of the in vivo application of the complex on selected biochemical parameters in healthy and diabetic Wistar rats were investigated. Strong antidiabetic effect associated with moderate hypoalbuminemia was observed. Furthermore, the interaction of complexes with BSA was studied by spectrofluorimetry. A significant conformational change of BSA in the presence of vanadium complexes was found. Synchronous fluorescence spectra revealed significant changes in the tyrosine microenvironment of BSA. The FRET analysis was also used and the non-radiative process of energy transfer is elucidated. Thermodynamic data suggest van der Waals forces and hydrogen bonding as predominant binding modes of complexes to BSA.

The two faces of pyocyanin - why and how to steer its production?

The ambiguous nature of pyocyanin was noted quite early after its discovery. This substance is a recognized Pseudomonas aeruginosa virulence factor that causes problems in cystic fibrosis, wound healing, and microbiologically induced corrosion. However, it can also be a potent chemical with potential use in a wide variety of technologies and applications, e.g. green energy production in microbial fuel cells, biocontrol in agriculture, therapy in medicine, or environmental protection. In this mini-review, we shortly describe the properties of pyocyanin, its role in the physiology of Pseudomonas and show the ever-growing interest in it. We also summarize the possible ways of modulating pyocyanin production. We underline different approaches of the researchers that aim either at lowering or increasing pyocyanin production by using different culturing methods, chemical additives, physical factors (e.g. electromagnetic field), or genetic engineering techniques. The review aims to present the ambiguous character of pyocyanin, underline its potential, and signalize the possible further research directions.

The Molecular Architecture of Pseudomonas aeruginosa Quorum-Sensing Inhibitors

The survival selection pressure caused by antibiotic-mediated bactericidal and bacteriostatic activity is one of the important inducements for bacteria to develop drug resistance. Bacteria gain drug resistance through spontaneous mutation so as to achieve the goals of survival and reproduction. Quorum sensing (QS) is an intercellular communication system based on cell density that can regulate bacterial virulence and biofilm formation. The secretion of more than 30 virulence factors of P. aeruginosa is controlled by QS, and the formation and diffusion of biofilm is an important mechanism causing the multidrug resistance of P. aeruginosa, which is also closely related to the QS system. There are three main QS systems in P. aeruginosa: las system, rhl system, and pqs system. Quorum-sensing inhibitors (QSIs) can reduce the toxicity of bacteria without affecting the growth and enhance the sensitivity of bacterial biofilms to antibiotic treatment. These characteristics make QSIs a popular topic for research and development in the field of anti-infection. This paper reviews the research progress of the P. aeruginosa quorum-sensing system and QSIs, targeting three QS systems, which will provide help for the future research and development of novel quorum-sensing inhibitors.