Search Results (7)

A zinc complex of chelidonic acid (4-oxo-4H-pyran-2,6-dicarboxylic acid) was obtained by reaction with zinc oxide under isothermal conditions. Its composition was confirmed by elemental and thermogravimetric analyses, and its molecular structure was characterized using NMR and IR spectroscopy. Single-crystal X-ray diffraction revealed that the complex crystallizes as a one-dimensional coordination polymer, [ZnChel(H₂O)₄]_n, in the triclinic space group P-1, featuring a distorted octahedral Zn(II) center coordinated by two chelidonate ligands and four water molecules. This six-coordinate arrangement contrasts with previously described tetra-coordinated Zn–chelidonate complexes. Quantum-chemical calculations and molecular dynamics simulations indicated that, in aqueous solution, Zn(II) preferentially forms a monodentate ZnChel(H₂O)₅ species, consistent with the solid-state coordination environment. The interaction of the complex with bovine serum albumin (BSA) was examined by fluorescence, UV–Vis absorption, and circular dichroism spectroscopy, revealing a mixed static–dynamic quenching mechanism, moderate binding affinity, and hydrogen-bonding/van der Waals contributions accompanied by alterations in BSA secondary structure. These results expand the structural chemistry of chelidonic acid and provide biophysical insight into the protein-binding behavior of zinc chelidonate, supporting its potential relevance as a zinc-based bioactive compound. Full article

The threatening phenomenon of antibiotic failure in the future determines the intensive research of antibacterial active compounds, which are promising candidates as antibiotics. Quinolines, with only the representative in clinical practice being Nitroxoline^TM, are, in addition to being effective beta-lactams, macrolides, tetracyclines, and other antibiotic categories, forgotten antibiotics. The antibacterial efficiency of Nitroxoline^TM and 2-aminoquinolin-8-ol on eight selected highly resistant bacterial species that are the most problematic (Klebsiella ssp., Enterococcus ssp., Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus) could lead to higher solubility and thus bioavailability and increased antibacterial effects. In the first phase, the basic salts of Nitroxoline^TM, with sodium hydroxide, benzylamine, 4-(aminomethyl)pyridine, and other primary amines, were synthesized. In the second phase, the corresponding acidic salts of 2-aminoquinolin-8-ol were synthesized with the following acids: oxalic acid, pyrazine-2,3-dicarboxylic acid, chelidonic acid, quinaldic acid, 3,5-dinitrosalycilic acid, quinoline-2-carboxylic acid, quinoline-3-carboxylic acid, kynurenic acid, and xanthurenic acid. Nitroxoline^TM and 2-aminoquinolin-8-ol both demonstrated moderate antibacterial effects, with the average value for the eight mentioned bacterial strains being 16 mg/L (84 μM) and 50 mg/L (301 μM), respectively. The synthetized salts of both quinolinols demonstrated significantly higher solubility and slightly increased antibacterial activity. The identity and purity of the prepared products were determined by NMR and IR spectroscopy. The MW values of both quinolinols are relatively low and offer better use of the largest molecule limit, defined by Lipinski’s rule of five at 500 g/M. The options of amines and acids offer the achievement of quaternary salts with improved antibacterial activity. Full article

This study investigated the effects of chelidonic acid (CA) on hydrogen peroxide (H₂O₂) induced cellular senescence in human skin fibroblast cells (BJ). Cellular senescence is a critical mechanism that is linked to age-related diseases and chronic conditions. CA, a γ-pyrone compound known for its broad pharmacological activity, was assessed for its potential to mitigate oxidative stress and alter senescence markers. A stress-induced premature senescence (SIPS) model was designed in BJ fibroblast cells using the oxidative stress agent H₂O₂. After this treatment, cells were treated with CA, and the potential effect of CA on senescence was evaluated using senescence-related β-galactosidase, 4′,6-diamino-2-phenylindole (DAPI), acridine-orange staining (AO), comet assay, molecular docking assays, gene expression, and protein analysis. These results demonstrate that CA effectively reduces senescence markers, including senescence-associated β-galactosidase activity, DNA damage, lysosomal activity, and oxidative stress indicators such as malondialdehyde. Molecular docking revealed CA’s potential interactions with critical proteins involved in senescence signalling pathways, suggesting mechanisms by which CA may exert its effects. Gene expression and protein analyses corroborated the observed anti-senescent effects, with CA modulating p16, p21, and pRB1 expressions and reducing oxidative stress markers. In conclusion, CA appeared to have senolytic and senomorphic potential in vitro, which could mitigate and reverse SIPS markers in BJ fibroblasts. Full article

Secondary varieties of date fruits are often discarded because they do not have commercial value. However, their phytochemicals are very similar to those of the primary ones and therefore, they can be valorized as a source of compounds of interest, mainly phenols and dietary fiber. Their chemical composition changes with ripening, so their characterization throughout this process is of great significance. Date fruit samples were harvested at Khalal, Rutab, and Tamer stages, and a mixture of fruits from ornamental date trees was also analyzed. Aqueous and ethanolic extracts were studied for their phenolic composition. In aqueous extracts, phenols decreased with ripening, while in the ethanolic ones having higher phenolic content. Chelidonic acid, a γ-pyrone, was the major compound found in all extracts, but in the ethanolic ones, flavonoids were also present in similar amounts. After purification by adsorption chromatography, all extracts were assayed for their antimicrobial activity. Those from the Tamer stage showed the highest activity, especially against Gram-positive bacteria. The fibrous residues after aqueous and ethanolic extractions were also characterized. Their chemical composition suggested that they can be considered as a good source of prebiotic arabinoxylans and antioxidant fiber, whose antiradical activity correlated with their phenolic content. Date fruits from secondary varieties are promising as a worthwhile starting point for obtaining new value-added products. Full article

Calcium chelidonate [Ca(ChA)(H₂O)₃]_n was obtained by semi-synthesis using natural chelidonic acid. The structure of the molecular complex was determined by X-ray diffraction analysis. The asymmetric unit of [Ca(ChA)(H₂O)₃]_n includes chelidonic acid coordinated through three oxygen atoms, and three water ligands. The oxygen atoms of acid and oxygen atoms of water from each asymmetric unit are also coordinated to the calcium of another one, forming an infinite linear complex. Calcium geometry is close to the trigonal dodecahedron (D2d). The intra-complex hydrogen bonds additionally stabilize the linear species, which are parallel to the axis. In turn the linear species are packed into the 3D structure through mutual intercomplex hydrogen bonds. The osteogenic activity of the semi-synthetic CaChA was studied in vitro on 21-day hAMMSC culture and in vivo in mice using ectopic (subcutaneous) implantation of CaP-coated Ti plates saturated in vitro with syngeneic bone marrow. The enhanced extracellular matrix ECM mineralization in vitro and ectopic bone tissue formation in situ occurred while a water solution of calcium chelidonate at a dose of 10 mg/kg was used. The test substance promotes human adipose-derived multipotent mesenchymal stromal/stem cells (hAMMSCs), as well as mouse MSCs to differentiate into osteoblasts in vitro and in vivo, respectively. Calcium chelidonate is non-toxic and can stimulate osteoinductive processes. Full article

The biomolecule chelidonic acid (H₂chel, 4-oxo-4H-pyran-2,6-dicarboxylic acid) has been used to build new coordination polymers with the bridging N,N′-ligands 4,4′-bipyridine (4,4-bipy) and 1,2-bis(4-pyridyl)ethane (bpe). Four compounds have been obtained as single crystals: 1D cationic coordination polymers [M(4,4-bipy)(OH₂)₄]²⁺ with chelidonate anions and water molecules in the second coordination sphere in ¹_∞[Zn(4,4-bipy)(H₂O)₄]chel·3H₂O (2) and in the two pseudopolymorphic ¹_∞[Cu(4,4-bipy)(H₂O)₄]chel·nH₂O (n = 3, 4a; n = 6, 4b), and the 2D neutral coordination polymers ²_∞[Zn(chel)(4,4-bipy)(H₂O)]·2H₂O (1) and ²_∞[Zn(chel)(bpe)(H₂O)]·H₂O (3) where the chelidonate anion acts as a bridging ligand. The effects of the hydrogen bonds on the crystal packing were analyzed. The role of the water molecules hosted within the crystals lattices was also studied. Full article

4-oxo-4H-pyran-2.6-dicarboxylic acid (chelidonic acid, ChA) in the native state and in the complex with calcium [Ca(ChA)(H₂O)₃], named saucalchelin (CaChA), was isolated from the extract of Saussurea controversa leaves for the first time for the Asteraceae family. The structure of ChA was determined by NMR, MS and confirmed by X-ray analysis of its monomethyl ester, and CaChA was described by IR, ICP-MS, CHN analysis. The yield of ChA and CaChA was 45 mg/g and 70 mg/g of extract, respectively. The osteogenic activity of ChA, n-monobutyl ester of chelidonic acid, and CaChA has been studied in vitro in a 21-day culture of human adipose-derived multipotent mesenchymal stromal cells (hAMMSCs) in a standard nutrient medium without osteogenic supplements. CaChA significantly stimulated the growth of cell mass and differentiation of hAMMSCs into osteoblasts with subsequent mineralization of the culture and it may be a promising substance for accelerating bone tissue regeneration and engineering. Full article