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Molecules (Basel, Switzerland) Apr 2022Chitosan (CS) and its derivatives are receiving considerable attention for their great biocompatibility and broad-spectrum activities in many fields. In this work, we...
Chitosan (CS) and its derivatives are receiving considerable attention for their great biocompatibility and broad-spectrum activities in many fields. In this work, we aimed to characterize the antimicrobial activity of novel chitosan Schiff bases (CSSB). CS was synthesized by double deacetylation of chitin (Cn) after its extraction from the armors of crustaceans , and CSSB-1 and CSSB-2 were synthesized by interaction of CS with 4-(2-chloroethyl) benzaldehyde (aldehyde-1) and 4-(bromoethyl) benzaldehyde (aldehyde-2), respectively, at room temperature. The synthesized compounds were characterized by elemental analysis, gel permeation chromatography (GPC), infrared spectroscopy (FTIR), thermogravimetry (TG), and differential scanning calorimetry (DSC). The antimicrobial activity against Gram-positive () and Gram-negative () bacteria and against yeasts () was significantly increased due to their higher solubility as compared to unmodified CS opening perspectives for the use of these compounds for antimicrobial prevention in different fields as, for example, food industry, cosmetics, or restoration.
Topics: Aldehydes; Anti-Bacterial Agents; Anti-Infective Agents; Benzaldehydes; Chitosan; Microbial Sensitivity Tests; Schiff Bases; Spectroscopy, Fourier Transform Infrared
PubMed: 35566088
DOI: 10.3390/molecules27092740 -
Metal Ions in Life Sciences Jan 2019The use of metals in medicine has grown impressively in recent years as a result of greatly advanced understanding of biologically active metal complexes and... (Review)
Review
The use of metals in medicine has grown impressively in recent years as a result of greatly advanced understanding of biologically active metal complexes and metal-containing proteins. One landmark in this area was the introduction of cisplatin and related derivatives as anticancer drugs. As the body of literature continues to expand, it is necessary to inspect sub-classes of this group with more acute detail. This chapter will review preclinical research of cobalt complexes coordinated by Schiff base ligands. Cobalt-Schiff base complexes have a wide variety of potential therapeutic functions, including as antimicrobials, anticancer agents, and inhibitors of protein aggregation. While providing a broad introduction to this class of agents, this chapter will pay particular attention to agents for which mechanisms of actions have been studied. Appropriate methods to assess activity of these complexes will be reviewed, and promising preclinical complexes in each of the following therapeutic areas will be highlighted: antimicrobial, antiviral, cancer therapy, and Alzheimer's disease.
Topics: Cobalt; Coordination Complexes; Ligands; Schiff Bases
PubMed: 30855112
DOI: 10.1515/9783110527872-017 -
International Journal of Molecular... Jul 2023As stated by two of the seven papers [...].
As stated by two of the seven papers [...].
Topics: Coordination Complexes; Schiff Bases; Ligands
PubMed: 37446197
DOI: 10.3390/ijms241311014 -
Molecules (Basel, Switzerland) Feb 2022Chemo and siRNA synergic treatments for tumors is a promising new therapeutic trend. Selenocystine, a selenium analog of cysteine, has been considered a potential...
Chemo and siRNA synergic treatments for tumors is a promising new therapeutic trend. Selenocystine, a selenium analog of cysteine, has been considered a potential antitumor agent due to its redox perturbing role. In this study, we developed a nanocarrier for siRNA based on a selenocystine analog engineered polyetherimide and achieved traceable siRNA delivery and the synergic killing of tumor cells. Notably, we applied the label-free Schiff base fluorescence mechanism, which enabled us to trace the siRNA delivery and to monitor the selenocystine analogs' local performance. A novel selenocystine-derived fluorescent Schiff base linker was used to crosslink the polyetherimide, thereby generating a traceable siRNA delivery vehicle with green fluorescence. Moreover, we found that this compound induced tumor cells to undergo senescence. Together with the delivery of a siRNA targeting the anti-apoptotic genes in senescent cells, it achieved a synergistic inhibition function by inducing both senescence and apoptosis of tumor cells. Therefore, this study provides insights into the development of label-free probes, prodrugs, and materials towards the synergic strategies for cancer therapy.
Topics: Cell Line, Tumor; Cell Survival; Cystine; Drug Delivery Systems; Fluorescence; Gene Transfer Techniques; Humans; Microscopy, Fluorescence; Molecular Structure; Nanocomposites; Organoselenium Compounds; RNA, Small Interfering; Schiff Bases
PubMed: 35209090
DOI: 10.3390/molecules27041302 -
Biochimica Et Biophysica Acta May 2014A fundamental design principle of microbial rhodopsins is that they share the same basic light-induced conversion between two conformers. Alternate access of the Schiff... (Review)
Review
A fundamental design principle of microbial rhodopsins is that they share the same basic light-induced conversion between two conformers. Alternate access of the Schiff base to the outside and to the cytoplasm in the outwardly open "E" conformer and cytoplasmically open "C" conformer, respectively, combined with appropriate timing of pKa changes controlling Schiff base proton release and uptake make the proton path through the pumps vectorial. Phototaxis receptors in prokaryotes, sensory rhodopsins I and II, have evolved new chemical processes not found in their proton pump ancestors, to alter the consequences of the conformational change or modify the change itself. Like proton pumps, sensory rhodopsin II undergoes a photoinduced E→C transition, with the C conformer a transient intermediate in the photocycle. In contrast, one light-sensor (sensory rhodopsin I bound to its transducer HtrI) exists in the dark as the C conformer and undergoes a light-induced C→E transition, with the E conformer a transient photocycle intermediate. Current results indicate that algal phototaxis receptors channelrhodopsins undergo redirected Schiff base proton transfers and a modified E→C transition which, contrary to the proton pumps and other sensory rhodopsins, is not accompanied by the closure of the external half-channel. The article will review our current understanding of how the shared basic structure and chemistry of microbial rhodopsins have been modified during evolution to create diverse molecular functions: light-driven ion transport and photosensory signaling by protein-protein interaction and light-gated ion channel activity. This article is part of a Special Issue entitled: Retinal Proteins - You can teach an old dog new tricks.
Topics: Archaea; Bacteriorhodopsins; Chlorophyta; Euryarchaeota; Halorhodopsins; Ion Channel Gating; Ion Transport; Light; Light Signal Transduction; Models, Molecular; Protein Conformation; Protons; Schiff Bases; Sensory Rhodopsins
PubMed: 23831552
DOI: 10.1016/j.bbabio.2013.06.006 -
Molecules (Basel, Switzerland) Aug 2019Schiff base, an important family of reaction in click chemistry, has received significant attention in the formation of self-healing hydrogels in recent years. Schiff... (Review)
Review
Schiff base, an important family of reaction in click chemistry, has received significant attention in the formation of self-healing hydrogels in recent years. Schiff base reversibly reacts even in mild conditions, which allows hydrogels with self-healing ability to recover their structures and functions after damages. Moreover, pH-sensitivity of the Schiff base offers the hydrogels response to biologically relevant stimuli. Different types of Schiff base can provide the hydrogels with tunable mechanical properties and chemical stabilities. In this review, we summarized the design and preparation of hydrogels based on various types of Schiff base linkages, as well as the biomedical applications of hydrogels in drug delivery, tissue regeneration, wound healing, tissue adhesives, bioprinting, and biosensors.
Topics: Animals; Click Chemistry; Drug Delivery Systems; Humans; Hydrogels; Schiff Bases; Tissue Adhesives; Wound Healing
PubMed: 31430954
DOI: 10.3390/molecules24163005 -
Drug Design, Development and Therapy 2022Silibinin (Sil), a flavonoid lignan-like natural compound derived from milk thistle seeds, has been used to treat hepatic diseases, including early-phase hepatocirrhosis...
BACKGROUND
Silibinin (Sil), a flavonoid lignan-like natural compound derived from milk thistle seeds, has been used to treat hepatic diseases, including early-phase hepatocirrhosis and fatty liver, for many years. However, its poor water solubility limits its gastrointestinal absorption and bioavailability. It clinical use has been limited due to its slow onset of action. Faced with this problem, research on the derivatives of silibinin has been receiving much attention.
PURPOSE
A series of silibinin derivatives with good biosafety and higher hepatoprotective activity were obtained by a safe, efficient and green chemical synthesis method.
PATIENTS AND METHODS
First, the carbonyl group in the structure of silibinin was used to obtain silibinin Schiff base derivatives by dehydration condensation with the carboxyl group in the sulfur-containing amino acid. Next, relevant experiments were performed to characterize the structure, physical form and solubility of the derivatives. Then, toxicity tests of the derivatives were performed in LO-2 cells and SD rats to evaluate their biosafety. Finally, the anti-inflammatory and antiapoptotic activities were observed using a carbon tetrachloride (CCl)-induced acute liver injury model in C57BL/6J mice using silibinin as a control.
RESULTS
The studies showed that SS and ST behaved as amorphous substances and showed a significant increase in solubility compared to silibinin. These two derivatives showed low toxicity in biosafety tests and higher bioactivity (anti-inflammatory and anti-apoptotic) than silibinin against acute liver injury induced by CCl.
CONCLUSION
Two silibinin derivatives (SS and ST) obtained by the Schiff base reaction improved the solubility of the silibinin parent nucleus in biological media with the help of the hydrophilic and amorphous morphology of the ligand. The low toxicity in vivo and in vitro ensures the biosafety of the derivatives. The hepatoprotective activity (anti-inflammatory and anti-apoptotic) was significantly improved compared to silibinin.
Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Carbon Tetrachloride; Chemical and Drug Induced Liver Injury; Liver; Mice; Mice, Inbred C57BL; Rats; Rats, Sprague-Dawley; Schiff Bases; Silybin; Silymarin
PubMed: 35601675
DOI: 10.2147/DDDT.S356847 -
Molecules (Basel, Switzerland) Oct 2023Toxic cations, including heavy metals, pose significant environmental and health risks, necessitating the development of reliable detection methods. This review... (Review)
Review
Toxic cations, including heavy metals, pose significant environmental and health risks, necessitating the development of reliable detection methods. This review investigates the techniques and approaches used to strengthen the sensitivity and selectivity of Schiff base fluorescent chemosensors designed specifically to detect toxic and heavy metal cations. The paper explores a range of strategies, including functional group variations, structural modifications, and the integration of nanomaterials or auxiliary receptors, to amplify the efficiency of these chemosensors. By improving selectivity towards targeted cations and achieving heightened sensitivity and detection limits, consequently, these strategies contribute to the advancement of accurate and efficient detection methods while increasing the range of end-use applications. The findings discussed in this review offer valuable insights into the potential of leveraging Schiff base fluorescent chemosensors for the accurate and reliable detection and monitoring of heavy metal cations in various fields, including environmental monitoring, biomedical research, and industrial safety.
Topics: Schiff Bases; Metals, Heavy; Fluorescent Dyes; Cations; Environmental Monitoring
PubMed: 37836803
DOI: 10.3390/molecules28196960 -
Molecules (Basel, Switzerland) Jun 2022A mixed-valent trinuclear complex with 1,3-bis(5-chlorosalicylideneamino)-2-propanol (Hclsalpr) was synthesized, and the crystal structure was determined by the...
A mixed-valent trinuclear complex with 1,3-bis(5-chlorosalicylideneamino)-2-propanol (Hclsalpr) was synthesized, and the crystal structure was determined by the single-crystal X-ray diffraction method at 90 K. The molecule is a trinuclear Co-Co-Co complex with octahedral geometries, having a tetradentate chelate of the Schiff-base ligand, bridging acetate, monodentate acetate coordination to each terminal Co ion and four bridging phenoxido-oxygen of two Schiff-base ligands, and two bridging acetate-oxygen atoms for the central Co ion. The electronic spectral feature is consistent with the mixed valent Co-Co-Co. Variable-temperature magnetic susceptibility data could be analyzed by consideration of the axial distortion of the central Co ion with the parameters Δ = -254 cm, = -58 cm, = 0.93, = 0.00436 cm mol, = -0.469 K, = 6.90, and = 2.64, in accordance with a large anisotropy. The cyclic voltammogram showed an irreversible reduction wave at approximately -1.2 V·vs. Fc/Fc, assignable to the reduction of the terminal Co ions.
Topics: 2-Propanol; Acetates; Crystallography, X-Ray; Ligands; Oxygen; Schiff Bases
PubMed: 35807456
DOI: 10.3390/molecules27134211 -
Molecules (Basel, Switzerland) Dec 2022Condensation of 2-hydroxybenzaldehyde (salicylaldehyde) or 2-hydroxy-1-naphthaldehyde with 2-ethylaniline yields the Schiff base compound of...
Condensation of 2-hydroxybenzaldehyde (salicylaldehyde) or 2-hydroxy-1-naphthaldehyde with 2-ethylaniline yields the Schiff base compound of ()-2-(((2-ethylphenyl)imino)methyl)phenol (HL) or ()-1-(((2-ethylphenyl)imino)methyl)naphthalen-2-ol (HL), which in turn react with the dinuclear complex of [Rh(η-cod)(µ-OCCH)] (cod = cycloocta-1,5-diene) to afford the mononuclear (η-cod){()-2-(((2-ethylphenyl)imino)methyl)phenolato-κN,O}rhodium(I), [Rh(η-cod)(L)] () or (η-cod){()-1-(((2-ethylphenyl)imino)methyl)naphthalen-2-olato-κN,O}rhodium(I), [Rh(η-cod)(L)] () (L or L = deprotonated Schiff base ligand). The X-ray structure determination revealed that the HL exists in the solid state not as the usual (imine)N···H-O(phenol) form (enolamine form) but as the zwitterionic (imine)N-H···O(phenol) form (ketoamine form). H NMR spectra for HL in different solvents demonstrated the existence of keto-enol tautomerism (i.e., keto ⇆ enol equilibrium) in solution. The structure for and showed that the deprotonated Schiff base ligand coordinates to the Rh(η-cod)-fragment as a six-membered N^O-chelate around the rhodium atom with a close-to-square-planar geometry. Two symmetry-independent molecules (with Rh1 and Rh2) were found in the asymmetric unit in in a structure with Z' = 2. The supramolecular packing in HL was organized by π-π and C-H···π contacts, while only two recognized C-H···π contacts were revealed in and . Remarkably, there were reciprocal or pairwise C-H···π contacts between a pair of each of the symmetry-independent molecules in . This pairwise C-H contact to the Rh-N^O chelate (metalloaromatic) ring may be a reason for the two symmetry-independent molecules in . Differential scanning calorimetry (DSC) analyses revealed an irreversible phase transformation from the crystalline-solid to the isotropic-liquid phase and subsequently confirmed the thermal stability of the compounds. Absorption spectra in solution were explained by excited state properties from DFT/TD-DFT calculations.
Topics: Schiff Bases; Crystallography, X-Ray; Ligands; Rhodium; Phenols
PubMed: 36615366
DOI: 10.3390/molecules28010172