Synthesis, molecular docking and biological evaluation of novel 6-(4-(4-aminophenylsulfonyl)phenylamino)-5H-benzo[a]phenothiazin-5-one derivatives

Biological Activity of Naphthoquinones Derivatives in the Search of Anticancer Lead Compounds

Naphthoquinones are a valuable source of secondary metabolites that are well known for their dye properties since ancient times. A wide range of biological activities have been described highlighting their cytotoxic activity, gaining the attention of researchers in recent years. In addition, it is also worth mentioning that many anticancer drugs possess a naphthoquinone backbone in their structure. Considering this background, the work described herein reports the evaluation of the cytotoxicity of different acyl and alkyl derivatives from juglone and lawsone that showed the best activity results from a etiolated wheat coleoptile bioassay. This bioassay is rapid, highly sensitive to a wide spectrum of activities, and is a powerful tool for detecting biologically active natural products. A preliminary cell viability bioassay was performed on cervix carcinoma (HeLa) cells for 24 h. The most promising compounds were further tested for apoptosis on different tumoral (IGROV-1 and SK-MEL-28) and non-tumoral (HEK-293) cell lines by flow cytometry. Results reveal that derivatives from lawsone (particularly derivative 4) were more cytotoxic on tumoral than in non-tumoral cells, showing similar results to those obtained with of etoposide, which is used as a positive control for apoptotic cell death. These findings encourage further studies on the development of new anticancer drugs for more directed therapies and reduced side effects with naphthoquinone skeleton.

Antibacterial and Antibiofilm Potency of Menadione Against Multidrug-Resistant S. aureus

Menadione is an analogue of 1,4-naphthoquinone (1,4-NQ) that possesses enormous pharmaceutical potential. The minimum inhibitory concentration (MIC) of menadione was determined against eighteen pathogens of the ESKAPE category, including thirteen multidrug-resistant (MDR) and five standard strains. From a total of eighteen pathogens, five strains of S. aureus (four: MDR and one: Standard strain) were considered further for detailed studies. This study included the determination of minimum bactericidal concentration (MBC), time-kill assay, scanning electron microscopic technique (SEM), and detection of reactive oxygen species (ROS). Additionally, the effect of menadione on biofilms of three strains of S. aureus was performed through crystal violet assay, SEM, and confocal laser scanning microscopy (CLSM). Menadione exerted substantial antibacterial activity against S. aureus (S8, S9, NCIM 5021) at a lower MIC (64 µg/mL). Whereas, the MIC of 256 µg/mL was displayed against J2 and J4 (MDR and biofilm-forming strains). The time-killing effect of menadione against S. aureus strains was observed after 9 h at MBCs of 64 µg/mL (NCIM 5021), 128 µg/mL (S8, S9), and 512 µg/mL (J2, J4). Enhanced levels of ROS in all five S. aureus were observed in presence of menadione (MICs and MBCs). The relation of enhanced ROS due to menadione activity invigorated us to explore its effect on S. aureus biofilms. We report menadione-mediated inhibition (> 90%) of biofilm formation (at respective MICs) and effect on preformed biofilms (> 85%) at 1024 µg/mL. Menadione possessing antibacterial and antibiofilm potentials are imperative in the era of multidrug resistance developed by bacterial pathogens.

Biopolymer and Synthetic Polymer-Based Nanocomposites in Wound Dressing Applications: A Review

Biopolymers are materials obtained from a natural origin, such as plants, animals, microorganisms, or other living beings; they are flexible, elastic, or fibrous materials. Polysaccharides and proteins are some of the natural polymers that are widely used in wound dressing applications. In this review paper, we will provide an overview of biopolymers and synthetic polymer-based nanocomposites, which have promising applications in the biomedical research field, such as wound dressings, wound healing, tissue engineering, drug delivery, and medical implants. Since these polymers have intrinsic biocompatibility, low immunogenicity, non-toxicity, and biodegradable properties, they can be used for various clinical applications. The significant advancements in materials research, drug development, nanotechnology, and biotechnology have laid the foundation for changing the biopolymeric structural and functional properties. The properties of biopolymer and synthetic polymers were modified by blending them with nanoparticles, so that these materials can be used as a wound dressing application. Recent wound care issues, such as tissue repairs, scarless healing, and lost tissue integrity, can be treated with blended polymers. Currently, researchers are focusing on metal/metal oxide nanomaterials such as zinc oxide (ZnO), cerium oxide (CeO₂), silver (Ag), titanium oxide (TiO₂), iron oxide (Fe₂O₃), and other materials (graphene and carbon nanotubes (CNT)). These materials have good antimicrobial properties, as well as action as antibacterial agents. Due to the highly antimicrobial properties of the metal/metal oxide materials, they can be used for wound dressing applications.

Design, synthesis, characterization, enzymatic inhibition evaluations, and docking study of novel quinazolinone derivatives

In this study, novel quinazolinone derivatives 7a-n were synthesized and evaluated against metabolic enzymes including α-glycosidase, acetylcholinesterase, butyrylcholinesterase, human carbonic anhydrase I, and II. These compounds exhibited high inhibitory activities in comparison to used standard inhibitors with K_i values in the range of 19.28-135.88 nM for α-glycosidase (K_i value for standard inhibitor = 187.71 nM), 0.68-23.01 nM for acetylcholinesterase (K_i value for standard inhibitor = 53.31 nM), 1.01-29.56 nM for butyrylcholinesterase (K_i value for standard inhibitor = 58.16 nM), 10.25-126.05 nM for human carbonic anhydrase I (K_i value for standard inhibitor = 248.18 nM), and 13.46-178.35 nM for human carbonic anhydrase II (K_i value for standard inhibitor = 323.72). Furthermore, the most potent compounds against each enzyme were selected in order to evaluate interaction modes of these compounds in the active site of the target enzyme. Cytotoxicity assay of the title compounds 7a-n against cancer cell lines MCF-7 and LNCaP demonstrated that these compounds do not show significant cytotoxic effects.

Simple Fluorescence Turn-On Chemosensor for Selective Detection of Ba2+ Ion and Its Live Cell Imaging

A phenoxazine-based fluorescence chemosensor 4PB [(4-(tert-butyl)-N-(4-((4-((5-oxo-5H-benzo[a]phenoxazin-6-yl)amino)phenyl)sulfonyl)phenyl)benzamide)] was designed and synthesized by a simple synthetic methods. The 4PB fluorescence chemosensor selectively detects Ba²⁺ in the existence of other alkaline metal ions. In addition, 4PB showed high selectivity and sensitivity for Ba²⁺ detection. The detection limit of 4PB was 0.282 μM and the binding constant was 1.0 × 10⁶ M^-1 in CH₃CN/H₂O (97.5:2.5 v/v, HEPES = 1.25 mM, pH 7.3) medium. This chemosensor functioned through the intramolecular charge transfer (ICT) mechanism, which was further confirmed by DFT studies. Live cell imaging in MCF-7 cells confirmed the cell permeability of 4PB and its capability for specific detection of Ba²⁺ in living cells.

Synthesis and Antimicrobial Evaluation of 1,4-Naphthoquinone Derivatives as Potential Antibacterial Agents

1,4-Naphthoquinones are an important class of compounds present in a number of natural products. In this study, a new series of 1,4-naphthoquinone derivatives were synthesized. All the synthesized compounds were tested for in vitro antimicrobial activity. In this present investigation, two Gram-positive and five Gram-negative bacterial strains and one pathogenic yeast strain were used to determine the antibacterial activity. Naphthoquinones tested for its antibacterial potencies, among seven of them displayed better antimicrobial activity against Staphylococcus aureus (S. aureus; 30-70 μg/mL). Some of the tested compounds showed moderate to low antimicrobial activity against Pseudomonas aeruginosa (P. aeruginosa) and Salmonella bongori (S. bongori; 70-150 μg/mL). In addition, most active compounds against S. aureus were evaluated for toxicity to human blood cells using a hemolysis assay. For better understanding, reactive oxygen species (ROS) generation, time-kill kinetic study, and apoptosis, necrosis responses were investigated for three representative compounds.

Highly Flexible Electrospun Hybrid (Polyurethane/Dextran/Pyocyanin) Membrane for Antibacterial Activity via Generation of Oxidative Stress

A hybrid nanofibrous mat consisting of polyurethane, dextran, and 10 wt % of biopigment (i.e., pyocyanin) was facilely fabricated using a direct-conventional electrospinning method. The field emission scanning electron microscopy showed the bead-free fibers with a twisted morphology for the pyocyanin-loaded mat. The addition of pyocyanin enables the unprecedented approach to tailor the hydrophilicity of hybrid mat, as verified from the water contact measurement. Thermomechanical stabilities of electrospun mats were investigated in terms of thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. The bacterial inhibition test revealed that the antibacterial activity of electrospun mat containing pyocyanin was 98.54 and 90.2% toward Escherichia coli and Staphylococcus aureus, respectively. By the combined efforts of rapid release of pyocyanin and oxidative stress, the PU-dextran-pyocyanin (PUDP) electrospun mat significantly declined the viable cell number that disrupts the cell morphology. Hence, the proposed PUDP electrospun mat must meet the requirements of efficient antimicrobial material in various applications such as disinfectant wiping, food packaging, and textile industries.