Abstract Oxime functionalization represents a promising strategy for modulating the physicochemical and biological properties of flavonoids, with the relationship to biological behavior remaining ill-defined. In this work, naringin and naringenin have been converted to their oximated derivatives through an optimized high-yield synthetic protocol. Both derivatives were characterized by elemental analysis, FT-IR, UV–Visible, NMR, ESI-MS, and, for the first time, X-ray crystallography. Spectroscopic analyses confirmed the transformation of the carbonyl group to oxime (C = N–OH) and revealed the presence of E/Z oxime isomers, while crystallographic analysis demonstrated the participation of the oxime group in hydrogen-bonding interactions in the crystal lattice. Oxime modification altered their electronic structure and solid-state fluorescence properties. Naringin-oxime exhibited improved solubility in biological media and was further evaluated biologically. It exhibited concentration- and tissue-dependent protective effects against H2O2-induced oxidative stress, under pre/post-treatment conditions, in neuronal cell models, and antibacterial activity against Gram(+) and Gram(−) bacteria. Complementary molecular docking studies provided insights into potential ligand–protein interactions with antioxidant- and antibacterial-related targets, thereby supporting the experimental observations. Collectively, the formulated structure–property–activity profile renders oximation a significant strategy for tuning flavonoid physicochemical and biological properties, thus highlighting flavonoid-oximes as multifunctional antibacterial and neuroprotective candidates.

A series of spin probes, bearing TEMPO, PROXYL or phosphorylated nitroxide paramagnetic groups attached to either terminal or internal position of an alkyl chain, are examined upon binding to bovine serum albumin, using an integrated spectroscopic, calorimetric, and computational approach. The structural diversity of spin probes allows a systematic investigation on how the type/position of paramagnetic moiety affect interaction. Electron paramagnetic resonance (EPR) and molecular docking reveal different dynamics of mid-chain and end-chain probes within distinct protein pockets. Mid-chain probes target deep hydrophobic sites, whereas end-chain probes reside near the protein-water interface. Phosphorylated nitroxides are strongly immobilized upon complexation, and lower the protein thermal stability. The highest enthalpy change of denaturation, linked to the lowest secondary structure perturbation, is determined by end-chain TEMPO. The collective results suggest that the nature and position of the paramagnetic moiety affect probe mobility and binding depth, while modulating the protein's conformational and thermal responses.

A series of dinuclear complexes were synthesized, involving vanadium with N-methylglycine (sarcosine)/N,N'dimethylglycine in aqueous media and H 2 O 2, capable of exerting catalytic activity. Specifically, the ternary V(V) tetraperoxido dinuclear species (NH4)2[V2O2(O2)4(CH3NH2CH2COO)] 4 ) 2 [V 2 O 2 (O 2 ) 4 (CH 3 NH 2 CH 2 COO)] (symmetric conformer) (1), 1 ), (NH4)2[V2O2(O2)4(CH3NH2CH2COO)] 4 ) 2 [V 2 O 2 (O 2 ) 4 (CH 3 NH 2 CH 2 COO)] (asymmetric conformer) (2), 2 ), K2(& Ncy;2 Omicron)[V2O2(O2)4(CH3NH2CH2COO)] 2 ( & Ncy; 2 Omicron )[V 2 O 2 (O 2 ) 4 (CH 3 NH 2 CH 2 COO)] . H2O 2 O (3) 3 ) (asymmetric conformer), and K2(& Ncy;2 Omicron)2[V2O2(O2)4{(CH3)2NHCH2COO)}] 2 ( & Ncy; 2 Omicron ) 2 [V 2 O 2 (O 2 ) 4 {(CH 3 ) 2 NHCH 2 COO)}] (4) 4 ) (asymmetric conformer) were synthetically isolated in crystalline form. Compounds 1 and 2 are the same, whilst with profound conformational differences exemplified through pH-specific chemistries. The new materials 1 - 4 were characterized by elemental analysis, FT-IR, Raman, NMR, and UV-Visible spectroscopy, cyclic voltammetry, thermogravimetric analysis (TGA-DTG), and X-ray crystallography. Further support of the spectroscopic and structural profile was achieved through Bond Valence Sum (BVS) and Hirshfeld molecular mapping calculations. In all of the studied compounds, pH appears to be a crucial factor in the synthesis and isolation. The physicochemical characterization of the hybrid materials justified further use of compound 3 as a potential hydroxylation catalyst of benzene under a variable set of mild reaction conditions. The products of the catalytic reaction systems investigated were identified and quantified by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID), respectively. The results a) exemplify the involvement of the hybrid dinuclear vanadium compounds in the pursued benzene transformations, and b) distinctly demonstrate the structural and chemical characteristics justifying the emergence of catalytic action of vanadium under mild conditions (40 degrees C) in reactions toward organic substrates (e.g. benzene) as the basis for the pursuit of selective industrial applications, affording readily available useful compounds.

Lanthanides have seen rapid growth in the pharmaceutical and biomedical field, thus necessitating the development of hybrid metal–organic materials capable of exerting defined biological activities. Ternary hybrid lanthanide compounds were synthesized through reaction systems of Ln(III) (Ln = La, Nd, Eu) involving the antioxidant flavonoid chrysin (Chr) and 1,10-phenanhtroline (phen) under solvothermal conditions, thus leading to pure crystalline materials. The so-derived compounds were characterized physicochemically in the solid state through analytical (elemental analysis), spectroscopic (FT-IR, UV-visible, luminescence, ESI-MS, circular dichroism, 151Eu Mössbauer), magnetic susceptibility, and X-ray crystallographic techniques. The analytical and spectroscopic data corroborate the 3D structure of the mononuclear complex assemblies and are in line with theoretical calculations (Bond Valence Sum and Hirshfeld analysis), with their luminescence suggesting quenching on the flavonoid-phen electronic signature. Magnetic susceptibility data suggest potential correlations, which could be envisioned, supporting future functional sensors. At the biological level, the title compounds were investigated for their (a) ability to interact with bovine serum albumin and (b) antibacterial efficacy against Gram(−) (E. coli) and Gram(+) (S. aureus) bacteria, collectively revealing distinctly configured biological profiles and suggesting analogous applications in cellular (patho)physiologies.

In this work, we studied the thermal behavior and infrared fingerprint of anhydrous and hydrated DL-tartaric acid via conventional and modulated Differential Scanning Calorimetry (DSC), Thermogravimetry (TGA), Fourier Transform Infrared Spectroscopy (FTIR), nuclear magnetic resonance (NMR), pH measurements, and ab initio density functional theory (DFT) calculations. Six samples were examined in total (raw, recrystallized from D2O solution, freeze-dried, and three heated samples). The results reveal that both forms (anhydrous and hydrated) do not exhibit melting prior to decomposition. It is also shown that the so-called DL-tartaric acid does not exist in the solid state in pure form, but it contains water and a tartaric acid oligomer, which is produced through esterification. Alteration of the chemical structure (reflected through decomposition) is initiated at quite low temperatures and is more pronounced for the hydrated form. Up to 75 °C, decomposition proceeds through esterification, while at higher temperatures it seems to be reversed due to the increase in water and decrease in COOH groups emerging through anhydride formation. Either upon heating or at sub-zero temperatures during freeze-drying, the hydrated form decomposes, and although some water is removed, new water is produced due to esterification. The conclusions are also supported by DFT calculations.

The attributes of Pb(II) as a metal ion, entering chemical reactivity in catalytic and non-catalytic systems of abiotic and biological nature, draw considerable attention, which directs efforts toward development of welldefined materials of technological interest. To that end, (di)carboxylic acids of variable chain length (C6-C10) have been employed to pursue the systematic synthetic and structural speciation of binary and ternary systems of Pb(II) in the presence of aromatic N,N'-containing chelators. Consequently, pH-specific synthetic efforts guided by molecular stoichiometry and reaction conditions (temperature, solvent, pressure) led to the isolation of crystalline coordination polymeric products, which were further characterized by elemental analysis, FT-IR, TGA-DTG, Luminescence, and X-ray diffraction. The structure and spectroscopic fingerprint of all investigated species attest to their unique Pb(II)-coordination geometry and associated chemistry, revealing ligand-binding modes and spatial characteristics accounting for their lattice architecture, in line with the increasing chain length of the dicarboxylic acid ligands employed. The arising features were further probed into through Bond Valence Sum and Hirshfeld analysis, thereby unraveling architectural insight into the unique physicochemical properties of all crystalline materials. The collective experimental data provide a well-defined profile of the chemistry in the ternary systems of Pb(II) with variable carbon chain-bound dicarboxylato ligands, when aromatic chelators enter the reactivity, thereby guiding generation of uniquely configured coordination polymers. Parameterization of the investigated systems of Pb(II) at the binary-ternary level formulate the luminescent properties displayed by the emerging metal-organic species, with the experimental and theoretical work supporting structural-optical correlations useful to the pursuit of advanced materials.

Neurodegenerative diseases have been increasingly plaguing the global population, with attempts to understand their etiopathogenesis and pursue therapeutics being at the forefront of multidisciplinary efforts. To that end, research was launched in our lab, based on natural products and bioessential metal ion complex forms to peruse their antioxidant and neuroprotective potential at the cellular level. To that end, the bioactivity profile of optimized Cornus mas L. extracts and supplemented mixtures thereof with soluble-bioavailable well-characterized hybrid materials, Zn(II)-Cit and V(IV)-Cit, was investigated. In vitro experiments on sensitive brain tissue cell lines (N2a58, SH-SY5Y) showed that the extracts and the metal complexes were atoxic (morphology, proliferation, chemotacticity) in a concentration-dependent manner. Subsequently, the antioxidant potential of all materials was examined, with H2O2 as the oxidizing agent, thereby revealing through viability and reactive oxygen species (ROS) visualization significant antioxidant activity, while specific genes (NFE2L2, Hmox1, GCLM) were crucial in divulging mechanistic aspects of the antioxidation. Concurrently, the anti-inflammatory activity was evaluated through gene expression ( TNF-a, IL-6), with Zn(II) bioavailability projecting intracellular levels linked to the observed sustainable activity. The collective bioactivity profile of the extracts and Zn(II)-Cit reveals significant neuroprotective properties, thereby meriting development of new naturally-based neutraceuticals that proactively avert neuropathological aberrations.

Development of new biologically active materials based on natural products has, over the years, attracted considerable attention due to their effectiveness in human health and disease. Polyphenolic compounds, particularly flavonoids, provide a wide range of health benefits, including antioxidant, anti-inflammatory, anticancer, and antibacterial properties. A series of novel Schiff base derivatives of flavonoids with amino-containing linkers was successfully designed and synthesized through condensation reactions. Naringin and naringenin derivatives with diamines, including ethylenediamine (EDA), 1,3-diamino-2-propanol (DA-2-PrOH), tetramethylenediamine (TMEDA), pentamethylenediamine (PMEDA), as well as polyamines spermidine (SPD) and spermine (SPM), were synthesized and well-characterized through FT-IR, UV-Visible, ESI-MS, 1H and 13C NMR spectroscopy, and elemental analysis. The so confirmed and well-characterized derivatives were subjected to photoluminescence studies, exhibiting enhanced activity, especially for naringin-based derivatives, and quenching in some others, thus verifying the significance of chemically modifying the conjugated systems of these molecules. Their biological activity was examined in the case of their antimicrobial efficacy against two Gram (+) (Staphylococcus aureus and Bacillus cereus) and two Gram (-) (Escherichia coli and Xanthomonas campestris) bacterial strains. Antibacterial screening projected selectivity of modified flavonoids against E. coli, proposing new "dense" flavonoid-(poly)amine materials as multifunctional antimicrobial agents and fluorescent probes.

Metal–organic compounds, and especially those containing well-known antioxidant natural flavonoids (Chrysin, Chr) and metal ions (Ti(IV)), attract keen interest for their potential biological activity nutritionally and pharmacologically. To that end, chemical reactivity profiling in binary/ternary systems was investigated synthetically, revealing unique structural correlations between mononuclear (Ti(IV)-Chr) and tetranuclear assemblies (Ti(IV)-Chr-phen). Chemical profiling involved physicochemical characterization through elemental analysis, FT-IR, UV–Visible, 1D-2D NMR, ESI-MS spectrometry, solid-state luminescence, and X-ray crystallography, with theoretical work on intra(inter)molecular interactions of 3D assemblies pursued through Hirshfeld analysis and BVS calculations. An in-depth study of their chemical reactivity shed light onto specific structural properties in the solid-state and in solution, while concurrently exemplifying quenching behavior due to their distinct flavonoid pattern. In the framework of biological activity, the materials were investigated for their antibacterial properties toward Gram(−)-E. coli and Gram(+)-S. aureus, exhibiting an enhanced effect compared to the free ligand and metal ion. Further investigation of BSA denaturation revealed strong anti-inflammatory properties compared to Chr and Diclofenac, an anti-inflammatory agent. Finally, in vitro studies using physiological and cancer cell lines, including breast (MCF10A, MCF7) and lung tissues (MRC-5, A549), formulated a structure–tissue relation reactivity profile, thus justifying their potential as future metallodrugs.

Non-aerated compost tea (CT) was prepared from compost derived from rockweed (Ascophyllum nodosum) and fish (cod, common ling, haddock, saithe) residues that fermented in water. Electrical conductivity, pH, concentrations of dry matter, ash, C, macronutrients (N, P, K, Ca, and Mg), and micronutrients (Cu, Fe, Mn, Mo, and Zn) of CT prepared under different fermentation conditions were measured. The effects of process factors, i.e., water/compost mass ratio (4.2–9.8 g/g) and fermentation time (4.2–9.8 days = 100–236 h), on the physicochemical properties of CT were quantified using quadratic polynomial models. CT obtained at optimal levels of process factors (4.2 g/g and 5.6 days = 134 h) was tested for lettuce seed germination and seedling growth. Diluted CT (25% CT + 75% ultrapure water) improved seedling growth while achieving a high germination percentage (97%).

Non-aerated compost tea was prepared from compost based on rockweed (Ascophyllum nodosum) residue fermented in water. Electrical conductivity, pH, dry mater, ash, macronutrient, micronutrient, and contaminant contents of compost tea prepared under different fermentation conditions were determined. The effects of fermentation process factors, i.e., water/compost mass ratio (4.2-9.8 g/g) and fermentation time (4.2-9.8 days = 100-236 h), on the relevant physicochemical properties of compost tea were quantified using second-order polynomial models. Optimal levels of fermentation process factors (4.2 g/g and 7 days = 168 h) were identified based on desirability function approach. Non-aerated compost tea produced under optimal fermentation conditions will be tested for lettuce germination and seedling growth. Recycling rockweed residues using composting and compost fermentation could have relevant positive effects on the environment and plant growth, development, and/or health.

There is a need to find novel sources of fertilizers to meet the increasing food demands of a growing human population and alternatives to mined and synthetic fertilizers for the certified organic sector. Composting is a common method for processing and stabilizing organic residues for use in horticulture. To that end, a small-scale composting experiment with six combinations of dried and ground rockweed (Ascophyllum nodosum), algae fiber from chemically processed rockweed, ground bones and fishmeal from cod (Gadus morhua), and ground blue mussels (Mytilus edulis) was conducted in Dewar flasks to assess whether these residues are suitable for composting and have potential for use as fertilizers. Expanded clay aggregates were used as a bulking material. Physicochemical analyses were performed on the residues and their mixtures before and after composting, and the temperature in the flasks was monitored for 92 days. Suitability was determined by evaluating the temperature dynamics, changes in physiochemical parameters, and nutrient profiles. All treatments generated heat, with reductions in C/N ratio, weight, and volume, demonstrating suitability for composting. The treatments with algae fiber had a higher mean temperature (34.5 vs. 29.0 °C) and more degree days above the thermophilic range (mean = 176- vs. 19-degree days), the greatest reduction in volume (mean = 35% vs. 27%), and the lowest C/N ratios at the end of active composting (18 vs. 24) compared to the treatments with dried and ground seaweed. In terms of fertilizer value, none of the finished composts were balanced for use as fertilizers alone and, in some cases, contained too much Na, but contained sufficient concentrations of K, S, Mg, and Ca and could be a valuable source of these nutrients and organic matter in combination with other N- and P-rich sources.

The diversity of metallodrugs used as diagnostics and therapeutics in disease treatment and their prevailing side -effects in human metabolism present an urgent need for exploration and development of new metal-based agents. Among them, rare earth metals constitute a unique case when combining with natural binders, such as anti-oxidant flavonoids. To that end, a multiparametric synthetic investigation of ternary systems of Er(III), Dy(III), Sm(III) with flavone chrysin and N,N'-aromatic chelator (phen) led to crystalline mononuclear materials, which were physicochemically characterized through elemental analysis, FT-IR, UV-Visible, ESI-MS, and X-ray crys-tallography. The coordination environment of trivalent lanthanides in each assembly reveals the salient features of ternary component binding modes, with the contribution of chrysin to lanthanide coordination validated though BVS and Hirshfeld surface analysis. The structural, electronic, and magnetics data of the new species signify the importance of structural speciation in drawing correlations with optical and magnetic properties, thus formulating well-defined physicochemical profiles and projecting essential attributes linked to the development of new materials of potential diagnostic-therapeutic value.

In a contemporary sustainable economy, innovation is a prerequisite to recycling waste into new efficient materials designed to minimize pollution and conserve non-renewable natural resources. Using an innovative approach to remediating metal-polluted water, in this study, eggshell waste was used to prepare two new low-cost nanoadsorbents for the retrieval of nickel from aqueous solutions. Scanning electron microscopy (SEM) results show that in the first eggshell–zeolite (EZ) adsorbent, the zeolite nanoparticles were loaded in the eggshell pores. The preparation for the second (iron(III) oxide-hydroxide)–eggshell–zeolite (FEZ) nanoadsorbent led to double functionalization of the eggshell base with the zeolite nanoparticles, upon simultaneous loading of the pores of the eggshell and zeolite surface with FeOOH particles. Structural modification of the eggshell led to a significant increase in the specific surface, as confirmed using BET analysis. These features enabled the composite EZ and FEZ to remove nickel from aqueous solutions with high performance and adsorption capacities of 321.1 mg/g and 287.9 mg/g, respectively. The results indicate that nickel adsorption on EZ and FEZ is a multimolecular layer, spontaneous, and endothermic process. Concomitantly, the desorption results reflect the high reusability of these two nanomaterials, collectively suggesting the use of waste in the design of new, low-cost, and highly efficient composite nanoadsorbents for environmental bioremediation.

Brown algae and fish waste contain high-value compounds with potentially beneficial effects on plant growth. Several commercial fertilizer products are currently available, but the characteristics of the materials are usually not well-described. Fish and seaweed residues originating from the Norwegian coast are available, after industrial processing, which may be combined into complete fertilizers exerting additional effects on crop plants (biostimulants). In this study, raw samples of fish and seaweed residues were investigated using ecofriendly technologies (drying, leaching), targeting search and isolation of potential biostimulants, followed by physicochemical characterization (elemental analysis, UV–visible, FT-IR, ICP-MS, ICP-OES, electrical conductivity, pH, etc.). Organic solvent extractions were employed to determine the available mineral content, micro- and macro-nutrients, antioxidant compounds, and amino acid content by chemical hydrolysis. The in vitro biotoxicity profile (cell viability, morphology, migration) of the generated extracts was also perused, employing Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli) along with sensitive neuronal eukaryotic cell lines N2a58 and SH-SY5Y, to assess their time- and concentration-dependent efficacy as antimicrobials and agents counteracting oxidative stress. The analytical composition of all raw materials showed that they contain important nutrients (K, P, Ca, N) as well as organic compounds and amino acids (Gly, Asp, Glu, Leu, Phe) capable of acting as plant biostimulants. Concurrently, the inherently high conductivity values and salt content necessitated leaching processes, which result in Na+ and K+ decreasing by more than ~60% and justifying further their use in soil treatment formulations. The aforementioned results and assertions, combined with physical measurements (pH, electrical conductivity, etc.) on naturally occurring and dried samples as well as green solvent extracts, formulated a physicochemical profile reflecting well-defined inorganic–organic species that might function as biostimulants. The collective physicochemical and biological properties support the notion that appropriate mixtures of marine organism residues may be efficient fertilizers for crop plants and concurrently possess biostimulant characteristics.

An outdoor experiment was performed for six months to evaluate the effects of organic fertilizers obtained from marine residual materials on strawberry plants. Three types of organic fertilizers were used, i.e., cod (Gadus morhua) bone powder, common ling (Molva molva) bone powder, and pellets obtained by mixing small cod bone powder and rockweed (Ascophyllum nodosum) residues. A tabletop system for strawberry cultivation was designed, in which two bare-root strawberry plants of cultivar ‘Albion’ were planted in a peat substrate in each pot. Five treatments were applied, i.e., cod bone powder (F1), common ling bone powder (F2), small cod bone powder and rockweed residue pellets (FA), chemical fertilizer (E), and a control (C). The number of leaves and their nutrient content, fruit yield and quality characteristics of the strawberries grown using the organic fertilizers were similar or better than those corresponding to treatments E and C. Organic fertilizers derived from the residues of fish and macroalgae could be a promising alternative to chemical fertilizers in strawberry production.

In contemporary sustainable economy, innovation is prerequisite to waste recycling into new efficient materials, designed to minimize pollution and conserve non-renewable natural resources. Water pollution is a global problem with health, quality of life, and food safety concerns. Thus, waste conversion into cheap, efficient adsorbent materials with high reusability is a challenge in wastewater recycling. In that context, starting from eggshell waste in this study, two new low-cost engineered adsorbents were prepared for the retrieval of nickel from aqueous solutions. Scanning electron microscopy (SEM) results show that, in the first eggshell-zeolite (EZ) adsorbent, the zeolite nanoparticles were loaded in the eggshell pores. The preparation for the second (iron(III) oxide-hydroxide)-eggshell-zeolite (FEZ) adsorbent led to double functionalization of the eggshell base with the zeolite nanoparticles, upon simultaneous loading of the pores of the eggshell and zeolite surface with FeOOH particles. Structural modification of the eggshell led to a significant increase of the specific surface, as confirmed by BET analysis. These features enabled the proposed adsorbents (EZ and FEZ) to remove nickel from aqueous solutions with high performance and adsorption capacities 321.1 mg/g and 287.9 mg/g, respectively. The results indicate that nickel adsorption on EZ and FEZ is a multi-molecular layer, spontaneous, and endothermic process. Concomitantly, desorption results reflect high reusability of these two adsorbents, collectively suggesting the use of waste in the design of new, low-cost, and highly efficient engineered adsorbents for environmental bioremediation

The prospect of developing soluble and bioavailable Ti(IV) complex forms with physiological substrates, capable of influencing (patho)physiological aberrations, emerges as a challenge in the case of metabolism-related pathologies (e.g., diabetes mellitus 1 and 2). To that end, pH-specific synthetic efforts on binary Ti(IV)-(α-hydroxycarboxylic acid) systems, involving natural physiological chelator ligands (α-hydroxy isobutyric acid, D-quinic acid, 2-ethyl-2-hydroxybutyric acid) in aqueous media, led to the successful isolation of binary crystalline Ti(IV)-containing products. The new materials were physicochemically characterized by elemental analysis, FT-IR, TGA, and X-ray crystallography, revealing in all cases the presence of mononuclear Ti(IV) complexes bearing a TiO6 core, with three bound ligands of variable deprotonation state. Solution studies through electrospray ionization mass spectrometry (ESI-MS) revealed the nature of species arising upon dissolution of the title compounds in water, thereby formulating a solid-state–solution correlation profile necessary for further employment in biological experiments. The ensuing cytotoxicity profile (pre-adipocytes and osteoblasts) of the new materials supported their use in cell differentiation experiments, thereby unraveling their structure-specific favorable effect toward adipogenesis and mineralization through an arsenal of in vitro biological assays. Collectively, well-defined atoxic binary Ti(IV)-hydroxycaboxylato complexes, bearing bound physiological substrates, emerge as competent inducers of cell differentiation, intimately associated with cell maturation, thereby (a) associating the adipogenic (insulin mimetic properties) and osteogenic potential (mineralization) of titanium and (b) justifying further investigation into the development of a new class of multipotent titanodrugs.

Novel antimicrobial compounds can be added to foods directly or incorporated into packaging materials in order to improve food safety and shelf life. One such potential antimicrobial compound is the bioinorganic complex Co(II)-citrate (NH4)(4)[Co(C6H5O7)(2)] (Co-cit). Its antimicrobial activity against Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa was investigated in solution, both alone and in combination with existing preservatives. The antimicrobial activity of poly(lactic acid) films (PLA) with incorporated Co-cit (23.3% w/w) against L. monocytogenes was determined using culture medium and model foods (slices of turkey ham and smoked salmon). In nutrient broth, without preservatives, all four bacteria were significantly (p < 0.05) inhibited by 0.5 mM Co-cit, and L. monocytogenes and P. aeruginosa were the most sensitive. The addition of preservatives to the broth increased the antimicrobial activity of Co-cit in many cases, but not in a way that was consistent between the different bacteria investigated and was likely due to additional physiological stress exerted on the cells rather than any effect on the activity of the Co-cit itself. PLA films with Co-cit were bacteriostatic against L. monocytogenes on artificial media and on foods. However, in the latter case, the PLA film itself was the main contributor to the inhibition. Composite PLA-(Co-cit) films exhibited antimicrobial activity against foodborne bacteria and have potential application as active packaging materials to enhance food safety.

Quercetin is one of the most bioactive and common dietary flavonoids, with a significant repertoire of biological and pharmacological properties. The biological activity of quercetin, however, is influenced by its limited solubility and bioavailability. Driven by the need to enhance quercetin bioavailability and bioactivity through metal ion complexation, synthetic efforts led to a unique ternary Ce(III)-quercetin-(1,10-phenanthroline) (1) compound. Physicochemical characterization (elemental analysis, FT-IR, Thermogravimetric analysis (TGA), UV-Visible, NMR, Electron Spray Ionization-Mass Spectrometry (ESI-MS), Fluorescence, X-rays) revealed its solid-state and solution properties, with significant information emanating from the coordination sphere composition of Ce(III). The experimental data justified further entry of 1 in biological studies involving toxicity, (Reactive Oxygen Species, ROS)-suppressing potential, cell metabolism inhibition in Saccharomyces cerevisiae (S. cerevisiae) cultures, and plasmid DNA degradation. DFT calculations revealed its electronic structure profile, with in silico studies showing binding to DNA, DNA gyrase, and glutathione S-transferase, thus providing useful complementary insight into the elucidation of the mechanism of action of 1 at the molecular level and interpretation of its bio-activity. The collective work projects the importance of physicochemically supported bio-activity profile of well-defined Ce(III)-flavonoid compounds, thereby justifying focused pursuit of new hybrid metal-organic materials, effectively enhancing the role of naturally-occurring flavonoids in physiology and disease.