1,4-Naphthoquinones have antibacterial activity and are a promising new class of compound that can be used to treat bacterial infections. The goal was to improve effective antibacterial agents; therefore, we synthesized a new class of naphthoquinone hybrids, which contain phenylamino-phenylthio moieties as significant counterparts. Compound 4 was modified as a substituted aryl amide moiety, which enhanced the antibacterial activity of earlier compounds 3 and 4. In this study, five bacterial strains Staphylococcus aureus (S. aureus), Listeria monocytogenes (L. monocytogenes), Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and Klebsiella pneumoniae (K. pneumoniae) were used to evaluate the antibacterial potency of synthesized naphthoquinones using the minimal inhibitory concentration (MIC) method. Most of the studied naphthoquinones demonstrated major antibacterial activity with a MIC of 15.6 µg/mL–500 µg/mL. Selected compounds (5a, 5f and 5x) were studied for the mode of action, using intracellular ROS generation, determination of apoptosis by the Annexin V-FITC/PI assay, a bactericidal kinetic study and in silico molecular modelling. Additionally, the redox potentials of the specified compounds were confirmed by cyclic voltammetry (CV).

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.

A new naphthoquinone-based chemosensor 2-((3hydroxyphenyl)amino)-3-(phenylthio)naphthalene-1,4-dione (2HPN) was successfully synthesized for the selective detection of Fe 2+ . The sensing property of the chemosensor 2HPN was evaluated in aqueous acetonitrile (CH 3 CN) medium by a fluorescence emission method. The metal-binding studies of the ligand 2HPN showed selective "turn-on" fluorescence responses for Fe 2+ (K a = 1.0 × 10 6 M −1 ). The detection limit of the ligand 2HPN to Fe 2+ was calculated to be 0.272 μM, which is lower than the World Health Organization recommendation (0.3 mg/L) in drinking water. The most significant feature of the obtained chemosensor 2HPN is its ability to sense Fe 2+ via naked-eye detection over various metal ions. The chemosensor operated via the intramolecular charge transfer effect, which was supported by Fourier transform infrared analysis, NMR titrations, and quantum chemical calculations. The efficiency of the chemosensor 2HPN as a biomarker for Fe 2+ was successfully proven by imaging in human cancer cells and zebrafish. Thus, the chemosensor 2HPN could be a useful biomarker for the precise sensing of Fe 2+ in clinical diagnosis.

1,4‐Naphthoquinones are exceptional building blocks in organic synthesis and have been used to synthesize several well‐known pharmaceutically active agents. Herein we report the synthesis, structural characterization, and biological evaluation of new phenylaminosulfanyl‐1,4‐naphthoquinone derivatives. We evaluated the cytotoxic activity of the synthesized compounds against three human cancer cell lines: A549, HeLa, and MCF‐7. Most of the synthesized compounds displayed potent cytotoxic activity. Specifically, compounds 5 e [3,5‐dichloro‐N‐(4‐((4‐((1,4‐dioxo‐3‐(phenylthio)‐1,4‐dihydronaphthalen‐2‐yl)amino)phenyl)sulfonyl)phenyl)benzamide], 5 f [N‐(4‐((4‐((1,4‐dioxo‐3‐(phenylthio)‐1,4‐dihydronaphthalen‐2‐yl)amino)phenyl)sulfonyl)phenyl)‐3,5‐dinitrobenzamide], and 5 p [N‐(4‐((4‐((1,4‐dioxo‐3‐(phenylthio)‐1,4‐dihydronaphthalen‐2‐yl)amino)phenyl)sulfonyl)phenyl)thiophene‐2‐carboxamide] showed remarkable cytotoxic activity. The synthesized compounds showed low toxicity in normal human kidney HEK293 cells. The cytotoxic mechanism of compounds 5 e, 5 f, and 5 p was explored in MCF‐7 cells. The results confirmed that these three compounds induce apoptosis and arrest the cell cycle at the G1 phase. In addition, compounds 5 e, 5 f, and 5 p were found to induce apoptosis via upregulation of caspase‐3 and caspase‐7 proteins as well as by upregulation of the gene expression levels of caspases‐3 and ‐7. Our findings demonstrate that compounds 5 e, 5 f, and 5 p could be potent agents against a number of cancer types.

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.