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Despite the common use of salens and hydroxyquinolines as therapeutic and bioactive agents, their metal complexes are still under development. Here, we report the synthesis of novel mixed-ligand metal complexes (MSQ) comprising salen (S), derived from (2,2′-{1,2-ethanediylbis[nitrilo(E) methylylidene]}diphenol, and 8-hydroxyquinoline (Q) with Co(II), Ni(II), Cd(II), Al(III), and La(III). The structures and properties of these MSQ metal complexes were investigated using molar conductivity, melting point, FTIR, 1H NMR, 13C NMR, UV–VIS, mass spectra, and thermal analysis. Quantum calculation, analytical, and experimental measurements seem to suggest the proposed structure of the compounds and its uncommon monobasic tridentate binding mode of salen via phenolic oxygen, azomethine group, and the NH group. The general molecular formula of MSQ metal complexes is [M(S)(Q)(H2O)] for M (II) = Co, Ni, and Cd or [M(S)(Q)(Cl)] and [M(S)(Q)(H2O)]Cl for M(III) = La and Al, respectively. Importantly, all prepared metal complexes were evaluated for their antimicrobial and anticancer activities. The metal complexes exhibited high cytotoxic potency against human breast cancer (MDA-MB231) and liver cancer (Hep-G2) cell lines. Among all MSQ metal complexes, CoSQ and LaSQ produced IC50 values (1.49 and 1.95 µM, respectively) that were comparable to that of cisplatin (1.55 µM) against Hep-G2 cells, whereas CdSQ and LaSQ had best potency against MDA-MB231 with IC50 values of 1.95 and 1.43 µM, respectively. Furthermore, the metal complexes exhibited significant antimicrobial activities against a wide spectrum of both Gram-positive and -negative bacterial and fungal strains. The antibacterial and antifungal efficacies for the MSQ metal complexes, the free S and Q ligands, and the standard drugs gentamycin and ketoconazole decreased in the order AlSQ > LaSQ > CdSQ > gentamycin > NiSQ > CoSQ > Q > S for antibacterial activity, and for antifungal activity followed the trend of LaSQ > AlSQ > CdSQ > ketoconazole > NiSQ > CoSQ > Q > S. Molecular docking studies were performed to investigate the binding of the synthesized compounds with breast cancer oxidoreductase (PDB ID: 3HB5). According to the data obtained, the most probable coordination geometry is octahedral for all the metal complexes. The molecular and electronic structures of the metal complexes were optimized theoretically, and their quantum chemical parameters were calculated. PXRD results for the Cd(II) and La(III) metal complexes indicated that they were crystalline in nature.

Three new Cu (II), Pd (II) and Ag (I) complexes of bidentate Schiff base ligand 2-[(4-chlorobenzylidene)amino] phenol (HL) were synthesized. The stoichiometric ratios and physicochemical properties of these complexes were determined using elemental analyses, magnetic measurements, infrared and UVvisible spectra, molar conductivity measurements and thermal analyses. The results revealed that the metal ions coordinated with through azomethine nitrogen and phenolic oxygen atoms. AgL and PdL complexes are present in a 1:1 molar ratio with square planar and tetrahedral geometry, respectively, while CuL 2 complex is present in a 1:2 molar ratio with octahedral geometry. The electronic structure and nonlinear optical parameters of HL and the studied 1:1 and 1:2 complexes were investigated theoretically at the DFT-B3LYP/6-311G** level of theory. The compounds were screened against various strains of bacteria and fungi. They displayed good results for inhibition against the studied pathogenic microorganisms. Absorption spectroscopic, viscosity and gel electrophoresis measurements were used for studying the interaction of the prepared complexes with calf thymus DNA (CT-DNA). The studied complexes showed a good interaction with CT-DNA via intercalation and groove modes. Moreover, molecular docking of these complexes was studied to understand the drug-DNA interactions and calculate the potential binding mode and energy. The anticancer effects of HL and its complexes, on selected human carcinoma cell lines, were determined. The cytotoxicity results showed that the prepared complexes are more potent than the Schiff base ligand.

Wound dressings created using nanotechnology are known as suitable substrates to speed up the healing of both acute and chronic wounds. Therapeutic substances can be delivered using these materials. In this study, a hydrogel loaded with Cu (II) Schiff base 8-hydroxy quinoline complex (CuSQ) solid lipid nanoparticles (SLN) was formulated to investigate its wound healing potential in an excision wound healing model in rats. The CuSQ SLN were spherical shaped with sizes ranging from 111 to 202 nm and a polydispersity index (PDI) ranging from 0.43 to 0.76, encapsulation efficiency (EE) % between 85 and 88, and zeta potential (ZP) of −11.8 to −40 mV. The formulated hydrogel showed good homogeneity, good stability, and a pH of 6.4 which indicates no skin irritation and had no cytotoxicity on the human skin fibroblast (HSF) cell line. In the in vivo study, animals were placed in five groups: control, standard, plain hydrogel, low dose, and high dose of CuSQ hydrogel. Both doses of CuSQ showed significantly faster healing rates compared to standard and control rats. In addition, the histopathology study showed more collagen, improved angiogenesis, and intact re-epithelization with less inflammation. A significant increase in transforming growth factor-beta1 (TGF-β1) level and increased immune expression of vascular endothelial growth factor (VEGF) by CuSQ treatment validates its role in collagen synthesis, proliferation of fibroblasts and enhancement of angiogenesis. Matrix metalloproteinase-9 (MMP-9) was found to be significantly reduced after CuSQ treatment. Immunohistochemistry of tumor necrosis factor alpha (TNF-α) revealed a marked decrease in inflammation. Thus, we concluded that CuSQ would be a beneficial drug for cutaneous wound healing since it effectively accelerated wound healing through regulation of various cytokines and growth factors.

Honey is known for its content of biomolecules, such as enzymes. The enzymes of honey originate from bees, plant nectars, secretions or excretions of plant-sucking insects, or from microorganisms such as yeasts. Honey can be characterized by enzyme-catalyzed and non-enzymatic reactions. Notable examples of enzyme-catalyzed reactions are the production of hydrogen peroxide through glucose oxidase activity and the conversion of hydrogen peroxide to water and oxygen by catalase enzymes. Production of hydroxymethylfurfural (HMF) from glucose or fructose is an example of non-enzymatic reactions in honey.

In this study, five novel complexes for Co(II), Ni(II), VO(II), Cr(III), and La(III) ions were synthesized from a tridentate NNO monobasic chelating Schiff base ligand, (Z)-2-((pyridin-2-ylimino)methyl)phenol (HL). Spectral and analytical tools were applied to elucidate the structural compositions of the new compounds. Then, geometry optimization was conducted for all the syntheses by the Gaussian 09 program via the density functional theory method to obtain optimal structures and the most essential parameters. Moreover, the biochemical behaviors of all the syntheses were explored based on the reactivity, which was tested against various cancer cell lines (HepG-2, MCF-7, and HCT-116). The complexes exhibited an interestingly antiproliferative potential against human cancer cell lines, and the cytotoxicities of the new complexes were arranged to follow the order: VOL > CrL > NiL > LaL > CoL > HL. The antioxidant behaviors of the complexes were studied using the DPPH assay, and VOL showed the maximum antioxidant activity, followed by LaL. The antibacterial activities of the HL ligand and its complexes were studied. Moreover, the binding nature of the complexes with calf thymus DNA (CT-DNA) was investigated based on the spectrophotometric absorption titration, viscosity, and gel electrophoresis methods. The binding ability of the complexes with CT-DNA was proposed to be just intercalation or replacement mode. The intrinsic binding constant K b was calculated and arranged based on the following order: VOL (5.2 Â 10 5 ) > CrL (3.6 Â 10 5 ) > NiL (3.3 Â 10 5 ) > LaL (3.0 Â 10 5 ) > CoL (1.12 Â 10 5 ) mol À1 dm À3 . Docking investigations were performed using the receptors of COVID-19's main protease viral protein (PDB ID: 6LU7) and Escherichia coli (gram [-ve] bacteria [PDB ID: 1fj4]).

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