Antimicrobial Zn2+-Carboxymethyl Chitosan Cryogel for Controlled Loading and Release of Ciprofloxacin via Coordination Bonds

The local application of broad-spectrum antibiotics via polymeric drug delivery systems is a promising alternative to their systemic administration in wound healing, prevention and treatment of infections associated with surgical implants. However, low and poorly controlled loading efficiency and 100% burst release are common problems for the materials with weak physical interaction between antibiotics and polymeric matrices. Here, we report a new multifunctional carboxymethyl chitosan (CMC) cryogel, which efficiently prevents bacterial adhesion to the surface, kills bacteria in the solution via controlled release of ciprofloxacin (CIP), and promotes fibroblast proliferation. The suggested approach is based on CIP loading to Zn2+-chelated CMC cryogel via the ligand exchange reaction. We have shown that, due to the strong binding of Zn2+ to CMC, the antibacterial effect and toxicity to fibroblasts of CMC-Zn-CIP cryogels were mainly determined by the content of loaded CIP, which can be precisely controlled via Zn2+ content in cryogel. CMC cryogels containing 20 mgZn/g can be loaded with CIP amounts sufficient to completely suppress the growth of hospital strain Klebsiella oxytoca with MIC of 0.125 µg/mL, while maintaining a fibroblast viability at the level of 85-90%.

The Effects of Different Treatments on Serum Trace Element Levels in Dogs with Heart Failure

The prognostic and diagnostic role of some trace elements in heart diseases has been demonstrated. In this study, the effects of min. 30-day and min. 120-day treatment with pimobendan, enalapril, and furosemide, as monotherapy and in combination, on serum trace element levels in dogs with heart failure were evaluated. A total of 107 dogs were treated with pimobendan or enalapril as monotherapy and pimobendan + enalapril (PE), enalapril + furosemide (EF), or pimobendan + enalapril + furosemide (PEF) as combination therapy for a min. of 30 and 120 days. Serum copper (Cu), zinc (Zn), iron (Fe), cobalt (Co), magnesium (Mg), manganese (Mn), selenium (Se), and chromium (Cr) were measured by an inductive coupled plasma optical emission spectroscopy device. Mean serum Mg in dogs treated with pimobendan for a min. of 120 days was significantly lower than that for a min. of 30 days (p < 0.05). In dogs using the PEF combination, mean serum Fe was significantly higher in the min. 120-day treatment group than in the min. 30-day treatment group (p < 0.01). No significant difference was observed in mean serum Cu, Zn, Co, Mn, Se, or Cr between the treatment groups and the time periods (p > 0.05). The short- and long-term use of pimobendan, enalapril, furosemide, and their combinations may cause changes in mean serum Mg and Fe in dogs with heart failure.

Design, synthesis, and computational analysis (molecular docking, DFT, MEP, RDG, ELF) of diazepine and oxazepine sulfonamides: biological evaluation for in vitro and in vivo anti-inflammatory, antimicrobial, and cytotoxicity predictions

We report the synthesis and extensive characterization of Diazepane and Oxazepane derivatives, followed by their biological evaluation. These compounds were assessed for in vitro and in vivo antimicrobial, anti-inflammatory, and anticancer activities. Among the synthesized molecules, compound 5b demonstrated remarkable antibacterial activity against Staphylococcus aureus and Staphylococcus epidermidis with MIC values of 20 and 40 μg/mL, respectively. Additionally, 5b exhibited potent anti-inflammatory effects both in vitro and in vivo. Advanced computational studies, including DFT, MEP, RDG, and ELF analyses, were performed to understand the electronic distribution and molecular interactions. The bioactivity and physicochemical properties of these derivatives were further predicted using PASS and pkCSM platforms, emphasizing their potential as promising lead molecules in drug development.

Coordination compounds of cobalt(II) with carboxylate non-steroidal anti-inflammatory drugs: structure and biological profile

Fourteen cobalt(II) complexes with the non-steroidal anti-inflammatory drugs sodium meclofenamate, tolfenamic acid, mefenamic acid, naproxen, sodium diclofenac, and diflunisal were prepared in the presence or absence of a series of nitrogen-donors (namely imidazole, pyridine, 3-aminopyridine, neocuproine, 2,2'-bipyridine, 1,10-phenanthroline and 2,2'-bipyridylamine) as co-ligands and were characterised by spectroscopic and physicochemical techniques. Single-crystal X-ray crystallography was employed to determine the crystal structure of eight complexes. The biological profile of the complexes was investigated regarding their interaction with serum albumins and DNA, and their antioxidant potency. The interaction of the compounds with calf-thymus DNA takes place via intercalation. The ability of the complexes to cleave pBR322 plasmid DNA at the concentration of 500 μM is rather low. The complexes demonstrated tight and reversible binding to human and bovine serum albumins and the binding site of bovine serum albumin was also examined. In order to assess the antioxidant activity of the compounds, the in vitro scavenging activity towards free radicals, namely 1,1-diphenyl-picrylhydrazyl and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), and their ability to reduce H2O2 were studied.

Unexpectedly high antibacterial ability of water in copper pot with tiny amount of plant leaves

Water disinfection by copper vessels has been prevalent over thousands of years. Unfortunately, people are still suffering from the bacterial pollution in drinking water. Here we show that, only through steeping with tiny amounts of common plant leaves, the room-temperature water in copper pots has unexpectedly high antibacterial ability. Remarkably, copper ions released from copper pots into water are in concentrations lower than the WHO safety threshold for drinking water, and have effective antibacterial ability when water contains specific leave components (polyphenols and/or lignin). Our computations show that the key to enhance antibacterial ability is the great increase in the proportion of Cu+ induced by aromatic rings in these leave components, which has been demonstrated by our experiments. The findings may disclose the mystery of copper vessels for water disinfection, and more importantly, provide effective antibacterial applications in industries and daily lives, by safely using copper ions together with biocompatible natural substances.

Recent Development of Fluoroquinolone Derivatives as Anticancer Agents

Cancer is the second leading cause of death in the world following cardiovascular disease. Its treatment, including radiation therapy and surgical removal of the tumour, is based on pharmacotherapy, which prompts a constant search for new and more effective drugs. There are high costs associated with designing, synthesising, and marketing new substances. Drug repositioning is an attractive solution. Fluoroquinolones make up a group of synthetic antibiotics with a broad spectrum of activity in bacterial diseases. Moreover, those compounds are of particular interest to researchers as a result of reports of their antiproliferative effects on the cells of the most lethal cancers. This article presents the current progress in the development of new fluoroquinolone derivatives with potential anticancer and cytotoxic activity, as well as structure-activity relationships, along with possible directions for further development.

Attaching Metal-Containing Moieties to β-Lactam Antibiotics: The Case of Penicillin and Cephalosporin

Procedures for the preparation of transition metal complexes having intact bicyclic cepham or penam systems as ligands have been developed. Starting from readily available 4-azido-2-azetidinones, a synthetic approach has been tuned using a copper-catalyzed azide-alkyne cycloaddition between 3-azido-2-azetinones and alkynes, followed by methylation and transmetalation to Au(I) and Ir(III) complexes from the mesoionic carbene Ag(I) complexes. This methodology was applied to 6-azido penam and 7-azido cepham derivatives to build 6-(1,2,3-triazolyl)penam and 7-(1,2,3-triazolyl)cepham proligands, which upon methylation and metalation with Au(I) and Ir(III) complexes yielded products derived from the coordination of the metal to the penam C6 and cepham C7 positions, preserving intact the bicyclic structure of the penicillin and cephalosporin scaffolds. The crystal structure of complex 28b, which has an Ir atom directly bonded to the intact penicillin bicycle, was determined by X-ray diffraction. This is the first structural report of a penicillin-transition-metal complex having the bicyclic system of these antibiotics intact. The selectivity of the coordination processes was interpreted using DFT calculations.

Erbium(III) complexes with fluoroquinolones: Structure and biological properties

Four erbium(III) complexes with the fluoroquinolones enrofloxacin, levofloxacin, flumequine and sparfloxacin as ligands were synthesized and characterized by a wide range of physicochemical and spectroscopic techniques as well as single-crystal X-ray crystallography. The compounds were evaluated for their activity against the bacterial strains Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Xanthomonas campestris, which was higher than that of the corresponding free quinolones. The interaction mode of the complexes with calf-thymus DNA is via intercalation, as suggested by diverse studies such as UV-vis spectroscopy, DNA-viscosity measurements and competitive studies with ethidium bromide. Fluorescence emission spectroscopy revealed the high affinity of the complexes for bovine and human serum albumin and the determined binding constants suggested a tight and reversible binding of the compounds with both albumins.

Marbofloxacin combined with heavy rare-earth ions makes better candidates for veterinary drugs: crystal structure and bio-activity studies

Marbofloxacin (MB) is a newly developed fluoroquinolone antibiotic used especially as a veterinary drug. It may be regarded as the improved version of enrofloxacin owing to its antibacterial activity, enhanced bioavailability, and pharmacokinetic-pharmacodynamic (PK-PD) properties. In this study, nine heavy rare-earth ions (Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) were selected in light of their potential antibacterial activity and satisfactory biosafety to afford the corresponding rare-earth metal complexes of MB: the MB-Ln series. Their chemical structures and coordination patterns were characterized using IR spectroscopy, HRMS, TGA, and X-ray single-crystal diffraction analysis. Our results confirmed that all the MB-Ln complexes yielded the coincident coordination modes with four MB ligands coordinating to the Ln(III) center. In vitro antibacterial screening on five typical bacteria strains revealed that the MB-Ln complexes exhibited antibacterial activities comparable with MB, as indicated by the MIC/MBC values, in which Escherichia coli and Salmonella typhi were the most sensitive ones to MB-Ln. Furthermore, the MB-Ln complexes were found to be much less toxic in vivo than MB, as suggested by the evaluated LD50 (50% lethal dose) values. All the MB-Ln series complexes fell in the LD50 range of 5000-15 000 mg kg-1, while the LD50 value of MB was only 1294 mg kg-1. Furthermore, MB-Lu, as the selected representative of MB-Ln, could effectively inhibit the activity of DNA gyrase, the same as MB, suggesting the primary antibacterial mechanism of the MB-Ln series. The results demonstrated the good prospects and potential of metal-based veterinary drugs with better drug performance.

Characterization, modes of interactions with DNA/BSA biomolecules and anti-tumor activity of newly synthesized dinuclear platinum(II) complexes with pyridazine bridging ligand

Platinum-based drugs are widely recognized efficient anti-tumor agents, but faced with multiple undesirable effects. Here, four dinuclear platinum(II) complexes, [{Pt(1,2-pn)Cl}2(μ-pydz)]Cl2 (C1), [{Pt(ibn)Cl}2(μ-pydz)]Cl2 (C2), [{Pt(1,3-pn)Cl}2(μ-pydz)]Cl2 (C3) and [{Pt(1,3-pnd)Cl}2(μ-pydz)]Cl2 (C4), were designed (pydz is pyridazine, 1,2-pn is ( ±)-1,2-propylenediamine, ibn is 1,2-diamino-2-methylpropane, 1,3-pn is 1,3-propylenediamine, and 1,3-pnd is 1,3-pentanediamine). Interactions and binding ability of C1-C4 complexes with calf thymus DNA (CT-DNA) has been monitored by viscosity measurements, UV-Vis, fluorescence emission spectroscopy and molecular docking. Binding affinities of C1-C4 complexes to the bovine serum albumin (BSA) has been monitored by fluorescence emission spectroscopy. The tested complexes exhibit variable cytotoxicity toward different mouse and human tumor cell lines. C2 shows the most potent cytotoxicity, especially against mouse (4T1) and human (MDA-MD468) breast cancer cells in the dose- and time-dependent manner. C2 induces 4T1 and MDA-MD468 cells apoptosis, further documented by the accumulation of cells at sub-G1 phase of cell cycle and increase of executive caspase 3 and caspase 9 levels in 4T1 cells. C2 exhibits anti-proliferative effect through the reduction of cyclin D3 and cyclin E expression and elevation of inhibitor p27 level. Also, C2 downregulates c-Myc and phosphorylated AKT, oncogenes involved in the control of tumor cell proliferation and death. In order to measure the amount of platinum(II) complexes taken up by the cells, the cellular platinum content were quantified. However, C2 failed to inhibit mouse breast cancer growth in vivo. Chemical modifications of tested platinum(II) complexes might be a valuable approach for the improvement of their anti-tumor activity, especially effects in vivo.

The Lung Microbiome in COPD and Lung Cancer: Exploring the Potential of Metal-Based Drugs

Chronic obstructive pulmonary disease (COPD) and lung cancer 17 are two of the most prevalent and debilitating respiratory diseases worldwide, both associated with high morbidity and mortality rates. As major global health concerns, they impose a substantial burden on patients, healthcare systems, and society at large. Despite their distinct aetiologies, lung cancer and COPD share common risk factors, clinical features, and pathological pathways, which have spurred increasing research interest in their co-occurrence. One area of particular interest is the role of the lung microbiome in the development and progression of these diseases, including the transition from COPD to lung cancer. Exploring novel therapeutic strategies, such as metal-based drugs, offers a potential avenue for targeting the microbiome in these diseases to improve patient outcomes. This review aims to provide an overview of the current understanding of the lung microbiome, with a particular emphasis on COPD and lung cancer, and to discuss the potential of metal-based drugs as a therapeutic strategy for these conditions, specifically concerning targeting the microbiome.

Simultaneous removal of pharmaceuticals and heavy metals from aqueous phase via adsorptive strategy: A critical review

The coexistence of pharmaceuticals and heavy metals is regarded as a serious threat to aquatic environments. Adsorbents have been widely applied to the simultaneous removal of pharmaceuticals and metals from aqueous phase. Through a comprehensive review, behaviors that promote, inhibit, or have no effect on simultaneous adsorption of pharmaceuticals and heavy metals were found to depend on the system of contaminants and adsorbents and their environmental conditions, such as: characteristics of adsorbent and pollutant, temperature, pH, inorganic ions, and natural organic matter. Bridging and competition effects are the main reasons for promoting and inhibiting adsorption in coexisting systems, respectively. The promotion is more significant in neutral or alkaline conditions. After simultaneous adsorption, a solvent elution approach was most commonly used for regeneration of saturated adsorbents. To conclude, this work could help to sort out the theoretical knowledge in this field, and may provide new insights into the prevention and control of pharmaceuticals and heavy metals coexisting in wastewater.

Interaction mechanism of Cu+/Cu2+ on bovine serum albumin: Vitro simulation experiments by spectroscopic methods

Copper (Cu) is an essential trace element for organisms, while excessive concentration of Cu is toxic. In order to assess the toxicity risk of copper in different valences, FTIR, fluorescence, and UV-vis absorption techniques were conducted to study the interactions between either Cu⁺ or Cu²⁺ and bovine serum albumin (BSA) under vitro simulated physiological condition. The spectroscopic analysis demonstrated that the intrinsic fluorescence emitted by BSA could be quenched by Cu⁺/Cu²⁺ via static quenching with binding sites 0.88 and 1.12 for Cu⁺ and Cu²⁺, respectively. On the other hand, the constants of Cu⁺ and Cu²⁺ are 1.14 × 10³ L/mol and 2.08 × 10⁴ L/mol respectively. ΔH is negative whereas ΔS is positive, showing that the interaction between BSA and Cu⁺/Cu²⁺ was mainly driven by electrostatic force. In accordance with Föster's energy transfer theory, the binding distance r showed that the transition of energy from BSA to Cu⁺/Cu²⁺ is highly likely to happen. BSA conformation analyses indicated that the interactions between Cu⁺/Cu²⁺ and BSA could alter the secondary structure of proteins. Current study provides more information of the interaction between Cu⁺/Cu²⁺ and BSA, and reveals the potential toxicological effect of different speciation of copper at molecular level.

Iron(III) Complexes with Non-Steroidal Anti-Inflammatory Drugs: Structure, Antioxidant and Anticholinergic Activity, and Interaction with Biomolecules

One the main research goals of bioinorganic chemists is the synthesis of novel coordination compounds possessing biological potency. Within this context, three novel iron(III) complexes with the non-steroidal anti-inflammatory drugs diflunisal and diclofenac in the presence or absence of the nitrogen donors 1,10-phenanthroline or pyridine were isolated and characterized by diverse techniques. The complexes were evaluated for their ability to scavenge in vitro free radicals such as hydroxyl, 1,1-diphenyl-2-picrylhydrazyl and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radicals, revealing their selective potency towards hydroxyl radicals. The in vitro inhibitory activity of the complexes towards the enzymes acetylcholinesterase and butyrylcholinesterase was evaluated, and their potential to achieve neuroprotection appeared promising. The interaction of the complexes with calf-thymus DNA was examined in vitro, revealing their ability to intercalate in-between DNA nucleobases. The affinity of the complexes for serum albumins was evaluated in vitro and revealed their tight and reversible binding.

Transition metal(II) complexes with the non–steroidal anti–inflammatory drug oxaprozin: Characterization and biological profile

A series of copper(II), nickel(II) and cobalt(II) complexes with the non-steroidal anti-inflammatory drug oxaprozin (Hoxa) have been synthesized and characterized by diverse techniques. The crystal structures of two copper(II) complexes, namely the dinuclear complex [Cu₂(oxa)₄(DMF)₂] (1) and the polymeric complex {[Cu₂(oxa)₄]·2MeOH·0.5MeOH}₂ (12) were determined by single-crystal X-ray diffraction studies. In order to evaluate in vitro the antioxidant activity of the resultant complexes, their scavenging ability towards 1,1-diphenyl-picrylhydrazyl (DPPH), hydroxyl and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals was investigated revealing their high effectiveness against these radicals. The binding of the complexes to bovine serum albumin and human serum albumin was examined and the corresponding determined albumin-binding constants showed a tight and reversible interaction. The interaction of the complexes with calf-thymus DNA was monitored by diverse techniques including UV-vis spectroscopy, cyclic voltammetry, DNA-viscosity measurements and competitive studies with ethidium bromide. Intercalation may be proposed as the most possible DNA-interaction mode of the complexes.

Metal Complexes with Naphthalene-Based Acetic Acids as Ligands: Structure and Biological Activity

Naproxen (6-methoxy-α-methyl-2-naphthaleneacetic acid), 1-naphthylacetic acid, 2-naphthylacetic acid and 1-pyreneacetic acid are derivatives of acetic acid bearing a naphthalene-based ring. In the present review, the coordination compounds of naproxen, 1- or 2-naphthylacetato and 1-pyreneacetato ligands are discussed in regard to their structural features (nature and nuclearity of metal ions and coordination mode of ligands), their spectroscopic and physicochemical properties and their biological activities.

Syntheses, Structural Characterization, and Cytotoxicity Assessment of Novel Mn(II) and Zn(II) Complexes of Aroyl-Hydrazone Schiff Base Ligand

This work describes the syntheses, structural characterization, and biological profile of Mn(II)- and Zn(II)-based complexes 1 and 2 derived from the aroyl-hydrazone Schiff base ligand (L1). The synthesized compounds were thoroughly characterized by elemental analysis, Fourier transform infrared spectroscopy (FTIR), UV-vis, electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), and single-crystal X-ray diffraction (s-XRD). Density functional theory (DFT) studies of complexes 1 and 2 were performed to ascertain the structural and electronic properties. Hirshfeld surface analysis was used to investigate different intermolecular interactions that define the stability of crystal lattice structures. To ascertain the therapeutic potential of complexes 1 and 2, in vitro interaction studies were carried out with ct-DNA and bovine serum albumin (BSA) using analytical and multispectroscopic techniques, and the results showed more avid binding of complex 2 than complex 1 and L1. The antioxidant potential of complexes 1 and 2 was examined against the 2,2-diphenyl picrylhydrazyl (DPPH) free radical, which revealed better antioxidant ability of the Mn(II) complex. Moreover, the antibacterial activity of synthesized complexes 1 and 2 was tested against Gram-positive and Gram-negative bacteria in which complex 2 demonstrated more effective bactericidal activity than L1 and complex 1 toward Gram-positive bacteria. Furthermore, the in vitro cytotoxicity assessment of L1 and complexes 1 and 2 was carried out against MDA-MB-231 (triple negative breast cancer) and A549 (lung) cancer cell lines. The cytotoxic results revealed that the polymeric Zn(II) complex exhibited better and selective cytotoxicity against the A549 cancer cell line as was evidenced by its low IC₅₀ value.

The anti-breast cancer stem cell properties of gold(i)-non-steroidal anti-inflammatory drug complexes

The anti-breast cancer stem cell (CSC) properties of a series of gold(i) complexes comprising various non-steroidal anti-inflammatory drugs (NSAIDs) and triphenylphosphine 1-8 are reported. The most effective gold(i)-NSAID complex 1, containing indomethacin, exhibits greater potency for breast CSCs than bulk breast cancer cells (up to 80-fold). Furthermore, 1 reduces mammosphere viability to a better extent than a panel of clinically used breast cancer drugs and salinomycin, an established anti-breast CSC agent. Mechanistic studies suggest 1-induced breast CSC death results from breast CSC entry, cytoplasm localisation, an increase in intracellular reactive oxygen species levels, cyclooxygenase-2 downregulation and inhibition, and apoptosis. Remarkably, 1 also significantly inhibits tumour growth in a murine metastatic triple-negative breast cancer model. To the best of our knowledge, 1 is the first gold complex of any geometry or oxidation state to demonstrate anti-breast CSC properties.

Nickel Complexes Bearing ONS Chelating Ligands: A Promising Contender for In Vitro Cytotoxicity Effects on Human Pancreatic Cancer MIA-PaCa-2 Cells

The highly chronic human pancreatic cancer cell is one of the major reasons for cancerous death. Nickel complexes are recently gaining interest in anticancer activities on different types of cancer cells. Hence, in this study, we synthesized and characterized a series of ONS donor ligands [2-HO-C₆H₄-CH═N-(C₆H₄)-SH] (L1), [2-OH-3-OMe-C₆H₃-CH═N-(C₆H₄)-SH] (L2), [2-OH-3,5-(C(Me)₃)₂-C₆H₂-CH═N-(C₆H₄)-SH] (L3), [2-OH-C₆H₄-CH═N-(C₆H₄)-SMe] (L4), [2-OH-3-OMe-C₆H₃-CH═N-(C₆H₄)-SMe] (L5), [2-OH-3,5-(C(Me)₃)₂-C₆H₂-CH═N-(C₆H₄)-SMe] (L6) and their Ni(II) metal complexes [(MeOH)Ni(L1-L1-4H)] (1), [(MeOH)Ni(L2-L2-4H)] (2), [(MeOH)Ni(L3-L3-4H)] (3), [(L4-H)₂Ni] (4), [(L5-H)₂Ni] (5), and [(L6-H)₂Ni] (6). The single-crystal X-ray diffraction data of complexes 1 and 4 were collected to elucidate the geometry around the metal center. The anticancer activity of complexes 1-6 was investigated on human pancreatic cancer cell line MIA-PaCa-2, which revealed that complexes 4 and 6 were the most significantly effective in decreasing the cell viability of cancer cells at the lowest dose. The structure parameters obtained from single-crystal X-ray diffraction data are found to be in good agreement with the data from density functional theory and Hirshfeld surface analysis for complex 1.

Zn-Catalyzed Regioselective and Chemoselective Reduction of Aldehydes, Ketones and Imines

An operationally convenient Zn-catalyzed synthesis of alcohols by the reduction of aldehydes, ketones, and α,β-unsaturated aldehydes/ketones is reported. It is a rare example of using mild and sustainable HBpin as a reductant for catalytic reduction of carbonyl compounds in the absence of acid or base as hydrolysis reagent. The reaction is upscalable and proceeds in high selectivity without the formation of boronate ester by-products, and tolerates sensitive functionalities, such as iodo, bromo, chloro, fluoro, nitro, trifluoromethyl, aminomethyl, alkynyl, and amide. The Zn(OAc)₂/HBpin combination has been also proved to be chemoselective for the C=N reduction of imine analogs.

Cucurbituril-Based Supramolecular Assemblies: Prospective on Drug Delivery, Sensing, Separation, and Catalytic Applications

Precise control over the stimuli-responsive noncovalent interactions operative in a complex molecular system has emerged as a convenient way to realize applications in the detection and sensing of trace analytes, metal ion separation, uptake-release, in situ nanoparticle synthesis, and catalytic activity. This feature article focuses on the attributes and advantages of noncovalent host-guest interactions involving cucurbituril homologues (CBs) with a wide range of organic and inorganic guests, starting from organic dyes to drugs, proteins, surfactants, metal ions, and polyoxometalates. The unique structural features of CBs provide interaction sites for cations at the portals, polyanions at the periphery, and hydrophobic groups in its cavity. The facile complexation and consequent compositional and geometrical arrangements of guests such as naphthalenediimides, coumarins, porphyrins, and triphenylpyrylium ions with the host CBs led to remarkable changes in many molecular properties, especially aggregation, the proton binding and release affinity, and novel emissive dimers, and each of such spectroscopic signatures have been appropriately channeled to drug delivery and activation to improve the antibacterial efficacy and shelf life of drugs by increasing their photostability. Several technological advantages have also been extracted from the interaction of CBs with inorganic guests as well. The interaction of CB7 with the heptamolybdate anion resulted in the precipitation of a hybrid complex material which enabled a convenient separation methodology for the use of clinically pure radioactive ^99mTc in diagnostic applications. Certain cucurbituril-based hybrid materials have been developed for enhanced SO₂ adsorption at low pressures, high-efficiency hydrogen production, and reversible catalytic systems. Thus, this feature article provides a glimpse of the vast potential of cucurbituril homologues with organic and inorganic guests and calls for a dedicated effort to explore supramolecular strategies for better sensors, therapeutics, smart drug delivery modules, and facile devices.

An Osteosarcoma Stem Cell Potent Nickel(II)-Polypyridyl Complex Containing Flufenamic Acid

Apoptosis resistance is inherent to stem cell-like populations within tumours and is one of the major reasons for chemotherapy failures in the clinic. Necroptosis is a non-apoptotic mode of programmed cell death that could help bypass apoptosis resistance. Here we report the synthesis, characterisation, biophysical properties, and anti-osteosarcoma stem cell (OSC) properties of a new nickel(II) complex bearing 3,4,7,8-tetramethyl-1,10-phenanthroline and two flufenamic acid moieties, 1. The nickel(II) complex 1 is stable in both DMSO and cell media. The nickel(II) complex 1 kills bulk osteosarcoma cells and OSCs grown in monolayer cultures and osteospheres grown in three-dimensional cultures within the micromolar range. Remarkably, 1 exhibits higher potency towards osteospheres than the metal-based drugs used in current osteosarcoma treatment regimens, cisplatin and carboplatin, and an established anti-cancer stem cell agent, salinomycin (up to 7.7-fold). Cytotoxicity studies in the presence of prostaglandin E2 suggest that 1 kills OSCs in a cyclooxygenase-2 (COX-2) dependent manner. Furthermore, the potency of 1 towards OSCs decreased significantly upon co-treatment with necrostatin-1 or dabrafenib, well-known necroptosis inhibitors, implying that 1 induces necroptosis in OSCs. To the best of our knowledge, 1 is the first compound to implicate both COX-2 and necroptosis in its mechanism of action in OSCs.

Nuclease-like metalloscissors: Biomimetic candidates for cancer and bacterial and viral infections therapy

Despite the extensive and rapid discovery of modern drugs for treatment of cancer, microbial infections, and viral illnesses; these diseases are still among major global health concerns. To take inspiration from natural nucleases and also the therapeutic potential of metallopeptide antibiotics such as the bleomycin family, artificial metallonucleases with the ability of promoting DNA/RNA cleavage and eventually affecting cellular biological processes can be introduced as a new class of therapeutic candidates. Metal complexes can be considered as one of the main categories of artificial metalloscissors, which can prompt nucleic acid strand scission. Accordingly, biologists, inorganic chemists, and medicinal inorganic chemists worldwide have been designing, synthesizing and evaluating the biological properties of metal complexes as artificial metalloscissors. In this review, we try to highlight the recent studies conducted on the nuclease-like metalloscissors and their potential therapeutic applications. Under the light of the concurrent Covid-19 pandemic, the human need for new therapeutics was highlighted much more than ever before. The nuclease-like metalloscissors with the potential of RNA cleavage of invading viral pathogens hence deserve prime attention.

Metal(II) Complexes of the Fluoroquinolone Fleroxacin: Synthesis, Characterization and Biological Profile

A series of complexes of divalent transition metals (Cu(II), Mn(II), Zn(II), Co(II) and Ni(II)) with the quinolone antibacterial agent fleroxacin, in the absence or presence of an α-diimine such as 2,2′-bipyridine, 1,10-phenanthroline or 2,2′-bipyridylamine, were prepared and characterized. The complexes were characterized by various physicochemical and spectroscopic techniques and by single-crystal X-ray crystallography. The in vitro antibacterial activity of the complexes was studied against the bacterial strains Staphylococcus aureus, Bacillus subtilis and Xanthomonas campestris and was higher than that of free quinolone. The affinity of the complexes for bovine and human serum albumin was studied by fluorescence emission spectroscopy and the determined binding constants showed tight and reversible binding to the albumins. The interaction of the complexes with calf-thymus DNA was studied by various techniques, which showed that intercalation was the most plausible mode of interaction.

Mixed Ni(II) and Co(II) complexes of nalidixic acid drug: Synthesis, characterization, DNA/BSA binding profile and in vitro cytotoxic evaluation against MDA-MB-231 and HepG2 cancer cell lines

In this work, herein we report the synthesis, structural characterization and in vitro cytotoxic evaluation of two mixed Co(II)/Ni(II)-nalidixic acid-bipyridyl complexes (1 and 2). The structural analysis of metal complexes 1 and 2 was carried out by analytical and multispectroscopic techniques (FT-IR, UV-vis, EPR, sXRD). The crystallographic details of complexes 1 and 2 revealed a monoclinic crystal system with P21/c space group. DFT studies of complexes were performed to get electronic structure and localization of HOMO and LUMO electron densities. Hirshfeld surface analysis of metal complexes 1 and 2 was employed to understand the various intermolecular interactions (C-H···O, N-H···H and O-H···O) that define the stability of crystal lattice structures. The comparative interaction studies of complex 1 and complex 2 with DNA/BSA were performed by diverse multispectroscopic and analytical techniques to evaluate their chemotherapeutic potential. The magnitude of the DNA binding propensity and binding mode was verified by calculating K_b, K and K_sv values. Higher binding affinity was observed in case of complex 2via intercalative mode. Furthermore, the cytotoxic assessment of complexes 1 and 2 was examined against MDA-MB-231 (triple negative human breast cancer cell line) and HepG2 (liver carcinoma cell line) employing MTT assay which revealed remarkably effecient and specific cytotoxic activity of complex 2.

NSAID-Based Coordination Compounds for Biomedical Applications: Recent Advances and Developments

After the serendipitous discovery of cisplatin, a platinum-based drug with chemotherapeutic effects, an incredible amount of research in the area of coordination chemistry has been produced. Other transition metal compounds were studied, and several new relevant metallodrugs have been synthetized in the past few years. This review is focused on coordination compounds with first-row transition metals, namely, copper, cobalt, nickel or manganese, or with zinc, which have potential or effective pharmacological properties. It is known that metal complexes, once bound to organic drugs, can enhance the drugs' biological activities, such as anticancer, antimicrobial or anti-inflammatory ones. NSAIDs are a class of compounds with anti-inflammatory properties used to treat pain or fever. NSAIDs' properties can be strongly improved when included in complexes using their compositional N and O donor atoms, which facilitate their coordination to metal ions. This review focuses on the research on this topic and on the promising or effective results that complexes of first-row transition metals and NSAIDs can exhibit.

Chromone‐Appended Zn(II) tRNA‐Targeted Potential Anticancer Chemotherapeutic Agent: Structural Details, in vitro ct‐DNA/tRNA Binding, Cytotoxicity Studies And Antioxidant Activity

A 3‐formyl‐chromone‐appended zinc(II) intercalator drug candidate of the formulation [bis(chromone)(H 2 O)2 Zn(II)] was prepared as a potent anticancer agent and thoroughly characterized by multi‐spectroscopic and single X‐ray crystallographic studies.   Preliminary binding studies of complex 1 with ct‐DNA/tRNA were carried out employing various complementary biophysical techniques and the corroborative results of these experiments suggested strong binding propensity via  intercalation binding mode towards ct‐DNA/tRNA  therapeutic targets, with higher preference for tRNA as quantified by  binding constant { K b , K and K sv } parameters. The cleavage studies with pBR322 DNA were performed which implied that 1 cleaved the DNA by hydrolytic cleavage pathway which was further validated by T4 religation assay. Moreover, 1  was found to exhibit the tRNA cleavage behavior in a concentration and time‐dependent manner. The cytotoxicity of complex 1 was evaluated against Huh‐7, DU‐145 and the PNT2 cell lines by MTT assay. A dose‐dependent growth inhibition of the Huh‐7 and DU‐145 cells at low micromolar concentrations was observed and in another set of experiments, lipid peroxidation & glutathione (GSH) depletion were induced in the presence of the tested drug candidate. Interestingly, drug candidate 1 demonstrated selective cytotoxic activity for the DU‐145 cancer cell line with LC50 value of 3.2 μM which was further visualized by confocal microscopy.

A New Calcium(II)-Based Substitute for Enrofloxacin with Improved Medicinal Potential

Enrofloxacin (EFX) reacting with Ca(II) afforded a new complex, [Ca(EFX)₂(H₂O)₄] (EFX-Ca), which was structurally characterized both in solid and solution chemistry. E. coli and S. typhi were tested to be the most sensitive strains for EFX-Ca. The LD₅₀ value of EFX-Ca in mice was 7736 mg/kg, implying the coordination of EFX to Ca(II) effectively reduced its acute toxicity. EFX-Ca also decreased the plasma-binding rate and enhanced the drug distribution in rats along with longer elimination half-life. EFX-Ca also showed similar low in vivo acute toxicity and higher anti-inflammation induced by H₂O₂ or CuSO₄ in zebrafish, with reactive oxygen species (ROS)-related elimination. The therapeutic effects of EFX-Ca on two types (AA and 817) of E. coli-infected broilers were also better than those of EFX, with cure rates of 78% and 88%, respectively. EFX-Ca showed promise as a bio-safe metal-based veterinary drug with good efficacy and lower toxicity.

Catalytic Hydroboration and Reductive Amination of Carbonyl Compounds by HBpin using a Zinc Promoter

In this paper, the chemoselective hydroboration of aldehydes and ketones, catalyzed by Zinc(II) complexes [ k 2 -(PyCH=NR)ZnX 2 ] [R = CPh 3 , X = Cl ( 1 ) and R = Dipp (2,6-diisoropylphenyl) and X = I ( 2 )], in the presence of pinacolborane (HBpin) in ambient temperature and solvent-free conditions, which produced corresponding boronate esters in high yield, is reported. Zinc metal complexes 1 and 2 were derived in 80-90% yield from the reaction of iminopyridine [PyCH=NR] with anhydrous zinc dichloride in dichloromethane at room temperature. The solid-state structures of both zinc complexes were confirmed using X-ray crystallography. Zinc complex 1 was also used as a competent pre-catalyst in the reductive amination of carbonyl compounds with HBpin under mild and solvent-free conditions to afford a high yield (up to 97%) of the corresponding secondary amines. The wider substrate scope of both reactions was explored. Catalytic protocols using zinc as a pre-catalyst demonstrated an atom-economic and green method with diverse substrates bearing excellent functional group tolerance. Computational studies established a plausible mechanism for catalytic hydroboration.

Antibiotic-metal complexes in wastewaters: fate and treatment trajectory

Unregulated usage, improper disposal, and leakage from pharmaceutical use and manufacturing sites have led to high detection levels of antibiotic residues in wastewater and surface water. The existing water treatment technologies are insufficient for removing trace antibiotics and these residual antibiotics tend to interact with co-existing metal ions and form antibiotic-metal complexes (AMCs) with altered bioactivity profile and physicochemical properties. Typically, antibiotics, including tetracyclines, fluoroquinolones, and sulphonamides, interact with heavy metals such as Fe²⁺, Co²⁺, Cu²⁺, Ni²⁺, to form AMCs which are more persistent and toxic than parent compounds. Although many studies have reported antibiotics detection, determination, distribution and risks associated with their environmental persistence, very few investigations are published on understanding the chemistry of these complexes in the wastewater and sludge matrix. This review, therefore, summarizes the structural features of both antibiotics and metals that facilitate complexation in wastewater. Further, this work critically appraises the treatment methods employed for antibiotic removal, individually and combined with metals, highlights the knowledge gaps, and delineates future perspectives for their treatment.

Synthesize and multi-spectroscopic studies of zinc-naproxen nanodrug as DNA intercalator agent

The zinc-naproxen complex as a nano-drug (NanoD) was synthesized successfully via fast and effective ultrasound-assisted processes. The chemicophysical properties of the NanoD were determined using FT-IR, XRD, SEM, and EDX mapping analyses. The results confirmed the formation of the 55 nm NanoD laminates. The interaction of the obtained NanoD with calf thymus deoxyribonucleic acid (CT-DNA) was studied as well. Structural and topography changes of DNA in interaction with the NanoD were investigated by atomic force microscopy (AFM). The results of electronic absorption spectroscopy, the DNA-viscosity studies, and competition fluorescence spectroscopy showed that CT-DNA binds to the NanoD through the intercalative binding mode. The data of AFM analysis indicated swollen CT-DNA upon interaction with the NanoD. The in vitro investigation of cytotoxicity of the NanoD on HT-29 and Hep G2 cancer cells demonstrated high cytotoxicity activity of the NanoD than that of cisplatin in HT-29 cell line, especially at lower concentrations.

Elucidation of DNA binding interaction of new Cu(II)/Zn(II) complexes derived from Schiff base and L-tryptophan amino acid: a multispectroscopic and molecular docking approach

Herein, we describe the synthesis, structural elucidation, and DNA interaction of newly synthesized Cu(II) and Zn(II) complexes, i.e., [Cu(SB)(L-trp)(H₂O)₂]NO₃ (1) and [Zn(SB)(L-trp)(H₂O)₂]NO₃ (2) (SB = Schiff base obtained from the reaction between o-vanillin and 2-amino-2-methylpropane-1,3-diol; L-trp = L-tryptophan). From the analysis, a six-coordinated environment around the Cu(II) or Zn(II) center is proposed. The ability of the complexes to bind with calf thymus DNA was examined by optical spectroscopy (UV-vis titrations and steady-state fluorescence emission) and viscosity measurements. The vivid experimental results revealed that complexes 1 and 2 avidly bind to DNA through surface and groove binding modes, albeit with dissimilar intrinsic binding constants (1.54 × 10⁴ and 1.36 × 10⁴ M^-1 for 1 and 2, respectively). Both complexes can displace ethidium bromide (EB) to some extent from the intercalated EB-DNA system, resulting in fluorescence quenching. Additional experiments such as [Fe(CN)₆]^4--induced quenching and thermal melting confirmed the electrostatic and groove binding mode. Furthermore, molecular docking studies verified that both complexes locate in the DNA minor groove by surface binding and were stabilized through weak intermolecular forces. The binding affinity of the lowest energy docked pose was found to be -5.37 kcal/mol for complex 1 and - 5.18 kcal/mol for complex 2. The present work is expected to pave the way for the synthesis of DNA-targeting Cu(II)/Zn(II) metal complexes for the development of chemotherapeutic agents.

DNA-and BSA-Binding Studies of Dinuclear Palladium(II) Complexes with 1,5-Naphtiridine Bridging Ligands

The interactions of metal complexes with important biomolecules such as deoxyribonucleic acid (DNA) or bovine serum albumin (BSA) are responsible for their antitumor activity due to different modes of interaction with DNA and their transport through the blood system to cells and tissues via serum albumin. Therefore, the dinuclear palladium(II) complexes, [{Pd(en)Cl}2(μ-1,5- nphe)](NO3)2 (Pd1) and [{Pd(1,3-pd)Cl}2(μ-1,5-nphe)](NO3)2 (Pd2) (en is ethylenediamine, 1,3-pd is 1,3-propylenediamine and 1,5-nphe is the bridging 1,5-naphthyridine ligand) were synthesized and characterized by different spectroscopic methods. The UV-Vis and fluorescence emission spectroscopy were applied for evaluation of binding modes of Pd1 and Pd2 complexes to DNA as well as their interaction with BSA. The emission spectra indicate that the investigated Pd1 and Pd2 complexes can displace the ethidium bromide intercalator from DNA/EtBr molecules and act as intercalators showing strong interactions with DNA. The fluorescence intensity showes that Pd1 and Pd2 complexes can bind to BSA and then be transported to the cell.

Ceftriaxone-based Schiff base transition metal(II) complexes. Synthesis, characterization, bacterial toxicity, and DFT calculations. Enhanced antibacterial activity of a novel Zn(II) complex against S. aureus and E. coli

From the reaction of ceftriaxone 1 antibiotic with 2,6-diaminopyridine 2 a ceftriaxone-based Schiff base (H₂L,3) was obtained and its transition metal complexes were synthesized. Spectroscopic and physicochemical techniques, namely, UV-visible, FT-IR, ¹H NMR, EPR, mass spectrometry, molar conductance, magnetic susceptibility and density functional theory (DFT) calculations, together with elemental and thermal analyses, were used to find out the binding mode and composition of these complexes. The ceftriaxone-based Schiff base 3 behaves as a monoanionic tridentate N,N,O ligand. Spectral and magnetic data suggest an octahedral geometry for all complexes and the general formulae [M(HL)(OAc)(H₂O)₂] (M(II) = Mn²⁺4, Co²⁺5, Ni²⁺6, Cu²⁺7, Zn²⁺8), are proposed for them. All compounds were screened for antibacterial activity using both the agar disc diffusion method and the minimal inhibitory concentration (MIC). It was found that complex 8 exhibited the most promising bactericidal activity against S. aureus (MIC = 0.0048 μmol/ml) and E. coli (MIC = 0.0024 μmol/ml). It is more active than the free ligand 1 (MIC = 0.0560 μmol/ml for S. aureus and 0.0140 μmol/ml for E. coli). These MIC results were compared with those obtained using similar zinc(II) Schiff base complexes, and with the values obtained using ceftriaxone conjugated with silver and gold nanoparticles (NPs), using earlier published data. Synthesized metal complexes exhibited LC₅₀ values >1000 ppm indicating their nontoxicity against brine shrimp nauplii (Artemia Salina).

Nickel(II)-meclofenamate complexes: Structure, in vitro and in silico DNA- and albumin-binding studies, antioxidant and anticholinergic activity

Five novel nickel(II) complexes with the non-steroidal anti-inflammatory drug sodium meclofenamate (Na-mclf) have been synthesized and characterized in the absence or co-existence of the nitrogen-donors imidazole (Himi), 2,2'-bipyridylamine (bipyam), 2,2'-bipyridylketoxime (Hpko) and 2,9-dimethyl-1,10-phenanthroline (neoc); namely [Ni(mclf-O)₂(Himi)₂(MeOH)₂], [Ni(mclf-O)₂(MeOH)₄], [Ni(mclf-O)(mclf-O,O')(bipyam)(MeOH)]·0.25MeOH, [Ni(mclf-O,O')₂(neoc)] and [Ni(mclf-O)₂(Hpko-N,N')₂]·MeOH·0.5H₂O. The affinity of the complexes for calf-thymus (CT) DNA was investigated by various techniques and intercalation is suggested as the most possible interaction mode. The interaction of the complexes for bovine and human serum albumins was also investigated in order to determine the binding constants, concluding that the complexes bind reversibly to albumins for the transportation towards their target cells or tissues and their release upon arrival at biotargets. The antioxidant activity of the compounds was evaluated via their ability to scavenge 1,1-diphenyl-picrylhydrazyl and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) free radicals and to reduce H₂O₂. For the determination of the anticholinergic ability of the complexes the in vitro inhibitory activity against the enzymes acetylcholinesterase and butyrylcholinesterase was evaluated and presented promising results. The in silico molecular modeling calculations employed provide useful insights for the understanding of the mechanism of action of the studied complexes at a molecular level. This applies on both the impairment of DNA by its binding with the studied complexes and transportation through serum albumins, as well as the ability of these compounds to act as anticholinergic agents.

Mechanistic studies of in vitro anti-proliferative and anti-inflammatory activities of the Zn(ii)-NSAID complexes of 1,10-phenanthroline-5,6-dione in MDA-MB-231 cells

Two zinc(ii)-NSAID complexes [(phendione)ZnII(NPR)2(H2O)2] (1) and [(phendione)ZnII(MFN)2] (2) (HNPR = naproxen and HMFN = mefenamic acid) of 1,10-phenanthroline-5,6-dione (phendione) were isolated and characterized to evaluate their potential as anti-cancer agents. Each of the complexes contains two equivalents of NSAID per zinc(ii)-phendione unit. The complexes are stable in solution under cell culture conditions. Cytotoxic assay on the human breast cancer cell line (MDA-MB-231) reveals that the anti-proliferative activity of phendione is retained in both the complexes. The anti-inflammatory properties of NSAIDs are also preserved in the metal complexes as evident from the PGE2 assay. Both 1 and 2 exhibit selective COX-1 inhibition at a low concentration. Furthermore, the zinc(ii)-naproxen complex (1) disrupts the intercellular bridges displaying in vitro delay in cellular migration and down-regulation of EMT-related genes. The mechanistic studies indicate that the ternary complexes are more active compared to cisplatin and have the potential to overcome cisplatin resistance in MDA MB 231 cells. These findings demonstrate that the zinc(ii)-NSAID complexes are worthy of further in vivo studies for their promising anti-tumor potential.