Synthesis, characterization, and antioxidant/cytotoxic activity of new chromone Schiff base nano-complexes of Zn(II), Cu(II), Ni(II) and Co(II)

Carrageenan-based functional films hybridized with carbon dots and anthocyanins from rose petals for smart food packaging applications

Multifunctional smart biopolymeric films were fabricated using rose petal anthocyanin (RPA) and carrageenan (CAR) doped with rose petal-derived carbon dots (RP-CDs). Response surface-optimized RPA showed the highest total anthocyanins and radical scavenging ability. Produced RP-CD exhibited UV absorption and high fluorescence with antibacterial/antioxidant abilities. Enrichment with 2 % RP-CD and 5 % RPA in the CAR matrix results in improved physicochemical, i.e., water contact angle, water vapor permeability, and UV-blocking properties of the fabricated material. Results showed that nanocomposite films scavenged radicals better than the neat CAR films. Zeta potential, FTIR, SEM, and XPS suggested improved compatibility/stability and enhanced elemental configuration of RP-CDs/RPA additives in the CAR polymer matrix. Perishable food packaging (minced pork and shrimp) demonstrated that nanocomposite films work efficiently and non-destructively and are promising tools for monitoring real-time freshness through interpretable visual changes from red to yellow. The CAR/RP-CDs/RPA-based nanocomposite indicator films are expected to be applied as various smart packaging materials. These films possess the ability to promptly detect changes in quality, preserve the quality, and prolong the shelf life of packaged foods.

Advances in chromone-based copper(ii) Schiff base complexes: synthesis, characterization, and versatile applications in pharmacology and biomimetic catalysis

Chromones are well known as fundamental structural elements found in numerous natural compounds and medicinal substances. The Schiff bases of chromones have a much wider range of pharmacological applications such as antitumor, antioxidant, anti-HIV, antifungal, anti-inflammatory, and antimicrobial properties. A lot of research has been carried out on chromone-based copper(ii) Schiff-base complexes owing to their role in the organometallic domain and promise as potential bioactive cores. This review article is centered on copper(ii) Schiff-base complexes derived from chromones, highlighting their diverse range of pharmacological applications documented in the past decade, as well as the future research opportunities they offer.

Synthesis, structural, spectroscopic and electric/dielectric studies of a nanocrystalline Ni(ii) complex based on [(1,3-diphenyl-1H-pyrazol-4-yl)methylene]thiocarbonohydrazide

A Ni2+ nanocomplex based on a heterocyclic ligand containing a pyrazole moiety was developed in this work, and its electric conductivity and dielectric characteristics were studied. The Ni2+ nanocomplex with the general formula [Ni(PyT)2(H2O)2]Cl2·½H2O, where PyT = [(1,3-diphenyl-1H-pyrazol-4-yl)methylene]thiocarbonohydrazide, was characterized using various techniques, including elemental and thermal analyses, as well as conductivity, magnetism, TEM, and spectroscopic (FT-IR, UV-Vis and XRD) studies. The results showed that PyT was bonded to the Ni(ii) centers via a neutral bidentate ligand, resulting in an octahedral-shaped, thermally stable mononuclear complex. The frequency response of the dielectric properties and ac conductivity was studied in the range from 200 Hz to 6 kHz. Both dielectric constant and dielectric loss decreased with increasing frequency. In addition, the effect of temperature was investigated in the range of 294.1-363.4 K. The ac conductivity increased with increasing temperature in the range of 294.1-333.5 K. The ac conduction is described as correlated barrier hopping between non-intimate valence alternation pairs. Furthermore, the PyT and Ni(PyT) nanocomplex structures were optimized using theoretical calculations and DFT computations.

Synthesis, spectral characterization, computational studies, antifungal, DNA interaction, antioxidant and fluorescence property of novel Schiff base ligand and its metal chelates

Cobalt, Copper, Nickel and Zinc coordinated metal complexes were synthesized by novel thiazole Schiff base ligand 2-ethoxy-4-((5-methylthiazol-2-ylimino)methyl) phenol derived from 3-ethoxy-4-hydroxybenzaldehyde and 2-amino- 5-methylthiazol. The synthesized compounds were spectrochemically characterized by elemental analysis, molar conductance, FT-IR, UV-Vis, Mass spectral analysis, Powdered-XRD and cyclic voltammetry. The thermal stability of synthesized complexes were investigated by using thermogravimetric analysis (TGA). Theoretical computational study were performed for all the synthesized compounds utilizing the DFT/B3LYP method at the 6-31G basic set for Schiff base ligand whereas LANL2DZ basis set for metal complexes. Molecular Electrostatic Potential (MEP), HOMO-LUMO, Mulliken charges and global reactivity descriptors, including chemical potential (μ), global softness (S), chemical hardness (η), and electrophilicity index (ω) were measured and correlated with antimicrobial activity. The synthesized thiazole Schiff base ligand and its coordinated metal complexes shows good antifungal agreement against Fusarium Oxysporum and Aspergillus Niger species. These compounds also exhibit DNA binding, DNA cleaving and antioxidant activity. All the synthesized molecules indicate potential fluorescence property.

Cellulose nanofiber-based multifunctional films integrated with carbon dots and anthocyanins from Brassica oleracea for active and intelligent food packaging applications

A new generation of carbon dot-based active and intelligent packaging films with UV blocking, antibacterial, and real-time sensing potentials was fabricated using Brassica oleracea (BO) extract. The cellulose nanofiber (CNF) was used to prepare the multifunctional intelligent nanocomposite film integrated with BO anthocyanins (BOA) and BO-biowaste-derived carbon dots (BO-CDs). The incorporation of 1.5 % BO-CD and 6 % BOA in the CNF matrix improved the physicochemical and UV blocking (>189 % increase) properties of the fabricated films. The synthesized BO-CD exhibits high fluorescence, UV absorption, antibacterial and antioxidant functions. It showed strong radical scavenging activity against ABTS (~90 %) and DPPH (~80 %) compared to the neat CNF film. Scanning electron microscopy and X-ray photoelectron spectroscopy (XPS) have shown enhanced compatibility and elemental composition of the BO-CDs/BOA additives in the CNF-polymer matrix. Packaging tests showed that the prepared film worked efficiently and non-destructively and was able to monitor the freshness of minced pork, fish, and shrimp in real-time through a distinct visual change from red to colorless/yellow during storage at 25 °C for 48 h. Active and intelligent films developed based on CNF/BO-CDs/BOA are expected to be applied as multifunctional packaging materials that can indicate quality changes and extend the shelf life of packaged perishable foods.

Novel electrospun fibers as carriers for delivering a biocompatible Sm(iii) nanodrug for cancer therapy: fabrication, characterization, cytotoxicity and toxicity

The current study represents the successful fabrication and characterization of a Sm(iii) nano complex based on 2-cyano-N'-((4-oxo-4H-chromen-3-yl)methylene)acetohydrazide (CCMA). The fibrous Sm(iii) nanocomplex has been fabricated by the electrospinning technique. SEM analysis of the electrospun fibers has revealed that the fibers have a uniform structure and smooth surface without observing Sm(iii) nanocomplex crystals, i.e. the Sm(iii) nanocomplex has been well incorporated into the fibers. In vitro antitumor activity against two carcinogenic cell lines (HepG-2 and E.A.C.) as well as in vivo toxicity of pure Sm(iii) nanocomplex and its electrospun fibers have been detected. The biological results have shown that there is a significant antitumor activity with low toxicity of the pure Sm(iii) nanocomplex and its electrospun fibers with respect to different standard antitumor drugs. Also, the electrospun fibers recorded higher cytotoxicity (IC₅₀ = 0.1 μM (Hep-G); 0.09 μM (E.A.C)) and lower toxicity (LD₅₀ = 350 mg kg^-1) than the pure ones. The in vitro release rate of the Sm(iii) nanocomplex from electrospun fibers has also been detected. The results have shown that the burst releasing of the Sm(iii) nanocomplex is about 22% after 1 h at the beginning, then a cumulative release increased gradually over the following hours. All results demonstrate the potential use of the Sm(iii) nanocomplex as a potent antitumor drug and its electrospun fibers as superior drug carriers for the treatment of tumors.

Copper(II) and oxidovanadium(IV) complexes of chromone Schiff bases as potential anticancer agents

We report the synthesis, characterization and biological screening of new chromone Schiff bases derived from the condensation of three 6-substituted-3-formyl-chromones with pyridoxal (HL^1-3) and its Cu(II) complexes [Cu(L^1-3)Cl], 1-3. For the 6-methyl derivative, HL², the V^IVO-complex [VO(L²)Cl] (5), as well as ternary Cu and V^IVO complexes with 1,10-phenanthroline (phen), [Cu(L²)(phen)Cl] (4) and [VO(L²)(phen)Cl] (6), were also prepared and evaluated. Their stability in aqueous medium and radical scavenging activity toward DPPH are screened, with [Cu(L²)(phen)Cl] (4) showing hydrolytic stability and [VO(L²)(phen)Cl] (6) high radical scavenging activity. Spectroscopic studies establish bovine serum albumin (BSA), a model for HSA, as a potential reversible carrier of [Cu(L²)(phen)Cl] in blood with K_BC ≈ 10⁵ M^-1. The cytotoxic activity of a group of compounds is evaluated against a panel of human cancer cell lines of different origin (ovary, cervix, brain and breast) and compared to normal cells. Our results indicate that Cu complexes are more cytotoxic than the ligands but not selective towards cancer cells. The most potent complexes (4 and 6) are further evaluated for their apoptotic potential, induction of reactive oxygen species (ROS) and genotoxicity. Both complexes efficiently triggered cell death through apoptosis as evaluated by DNA morphology and TUNEL assay, increased ROS formation as determined by DCFDA (2',7'-dichlorodihydrofluorescein diacetate) analysis, and induced genotoxic damage as visualized via COMET assay in all cancer cells under study. Therefore, 4 and 6 may be potential precursor anticancer molecules, yet they need to be targeted toward cancer cells.

Chromone a Privileged Scaffold in Drug Discovery: Developments on the Synthesis and Bioactivity

Chromones are the class of secondary metabolites broadly occurred in the plant kingdom in a noticeable quantity. This rigid bicyclic system has been categorized "as privileged scaffolds in compounds" in medicinal chemistry. The wide biological responses made them an important moiety in a drug discovery program. This review provides updates on the various methods of synthesis of chromones and biological applications in medicinal chemistry. Various synthetic strategies for the construction of chromones include readily available phenols, salicylic acid and its derivatives, ynones, chalcones, enaminones, chalcones and 2-hydroxyarylalkylketones as starting materials. Synthesis of chromones by using metal, metal free, nanomaterials and different catalysts are included. Details of diverse biological activities such as anti-cancer agents, antimicrobial agents, anti-viral property, anti-inflammatory agents, antioxidants, Monoamine Oxidase-B (MAO-B) Inhibitors, anti-Alzheimer's agents, anti-diabetic agent, antihistaminic potential, antiplatelet agents of chromone derivatives are diecussed.

Co(ii), Ni(ii), Cu(ii) and Cd(ii)-thiocarbonohydrazone complexes: spectroscopic, DFT, thermal, and electrical conductivity studies

New and stable coordinated compounds have been isolated in a good yield. The chelates have been prepared by mixing Co(ii), Ni(ii), Cu(ii), and Cd(ii) metal ions with (1E)-1-((6-methyl-4-oxo-4H-chromen-3-yl)methylene)thiocarbonohydrazide (MCMT) in 2 : 1 stoichiometry (MCMT : M²⁺). Various techniques, including elemental microanalyses, molar conductance, thermal studies, FT-IR, ¹H-NMR, UV-Vis, and XRD spectral analyses, magnetic moment measurements, and electrical conductivity, were applied for the structural and spectroscopic elucidation of the coordinating compounds. Further, computational studies using the DFT-B3LYP method were reported for MCMT and its metal complexes. MCMT behaves as a neutral NS bidentate moiety that forms octahedral complexes with general formula [M(MCMT)₂Cl(OH₂)]Cl·XH₂O (M = Cu²⁺; (X = ½), Ni²⁺, Co²⁺; (X = 1)); [Cd(MCMT)₂Cl₂]·½H₂O. There is good confirmation between experimental infrared spectral data and theoretical DFT-B3LYP computational outcomes where MCMT acts as a five-membered chelate bonded to the metal ion through azomethine nitrogen and thiocarbonyl sulphur donors. The thermal analysis is studied to confirm the elucidated structure of the complexes. Also, the kinetic and thermodynamic parameters of the thermal decomposition steps were evaluated. The measured optical band gap values of the prepared compounds exhibited semiconducting nature. AC conductivity and dielectric properties of the ligand and its complexes were examined, which showed that Cu(ii) complex has the highest dielectric constant referring to its high polarization and storage ability.

Transition metal complexes of a multidentate Schiff base ligand containing pyridine: synthesis, characterization, enzyme inhibitions, antioxidant properties, and molecular docking studies

A series of Fe(II), Ni(II), and Pd(II) complexes were prepared with a novel Schiff base ligand containing pyridine moiety. The prepared compounds were characterized using FT-IR, ¹H and ¹³ C NMR, UV-Vis, powder XRD, thermogravimetric analysis, mass spectra, magnetic susceptibility, and elemental analysis. The coordination geometry of Fe(II) and Ni(II) complexes were octahedral, where Fe(II) and Ni(II) metal ions were coordinated by an oxygen atom of the carbonyl group, a nitrogen atom of the azomethine moiety, and a phenolic oxygen atom. The Pd(II) complex had square planar geometry. All of the synthesized compounds were tested for their biochemical properties, including enzyme inhibition and antioxidant activities. According to the in vitro DPPH and FRAP antioxidant methods, the Schiff base ligand and its Fe(II)/Pd(II) complexes showed close antioxidant activities against the standards (BHA, BHT, ascorbic acid, and α-tocopherol). Enzyme inhibitions of the metal complexes were investigated against glutathione S-transferase (GST), acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) enzymes. The best inhibition value (K_i) was observed for the Ni(II) complex against GST (2.63 ± 0.04 µM). Also, the Pd(II) complex showed the best inhibition value (10.17 ± 1.88 µM) against AChE. Molecular docking specified significant interactions at the active pockets of respective target enzymes. The Ni(II) complex exhibited good binding affinity against both BChE (- 9.0 kcal/mol and 9.36 ± 2.03 µM) and GST (- 7.0 kcal/mol and 2.63 ± 0.04 µM) enzymes.

Influence of DMβCD on the Interaction of Copper(II) Complex of 6-Hydroxychromone-3-carbaldehyde-3-hydroxybenzoylhydrazine with ctDNA

The interaction mechanism between a scarcely soluble copper(II) complex of Cu(II)-6-hydroxychromone-3-carbaldehyde-(3'-hydroxy)benzoylhydrazone (CuCHz) in aqueous solution and its DMβCD complex was studied in the presence of ctDNA through spectroscopy and thermodynamic methods. The thermodynamic results indicate that the binding process of the CuCHz-DMβCD inclusion complex is a spontaneous process and the inclusion is enthalpy-driven. The binding constants of CuCHz and CuCHz-DMβCD with ctDNA are 2.69 × 10³ and 14.7 × 10³ L mol^-1, respectively. The stoichiometry of the complex is 1:1, and the determined thermodynamic indicates that the process of binding is spontaneous and entropy-driven. A competitive binding titration with ethidium bromide revealed that CuCHz efficiently displaces EB from the EB-DNA system. In addition to the thermal denaturation experiments and docking studies, we can confirm that the mode of binding of this complex to ctDNA is intercalation mode. The presence of DMβCD enhances the aqueous solubility of CuCHz; nevertheless, the cyclodextrin did not affect the interaction of CuCHz with ctDNA because the inclusion complex breaks down when it binds with ctDNA.

Metal Complexes of Natural Product Like-compounds with Antitumor Activity

Cancer continues to be one of the major causes of death worldwide. Despite many advances in the understanding of this complex disease, new approaches are needed to improve the efficacy of current therapeutic treatments against aggressive tumors. Natural products are one of the most consistently successful sources of drug leads. In recent decades, research activity into the clinical potential of this class of compounds in cancer has increased. Furthermore, a highly promising field is the use of metals and their complexes in the design and development of metal-based drugs for the treatment of cancer. Metal complexes offer unique opportunities due to their ability to alter pharmacology, improving the efficacy and/or reducing the negative side effects of drug molecules. In addition, transition metals as copper, iron, and manganese, among others, can interact with active sites of enzymes, playing important roles in multiple biological processes. Thus, these complexes not only possess higher activities but also reach their targets more efficiently. This review article highlights recent advances on the emerging and expanding field of metal-based drugs. The emphasis is on new therapeutic strategies consisting of metal complexes with natural product like-compounds as a starting point for the rational design of new antitumor agents.