Analgesic and anti-inflammatory activities of salicylaldehyde 2-chlorobenzoyl hydrazone (H(2)LASSBio-466), salicylaldehyde 4-chlorobenzoyl hydrazone (H(2)LASSBio-1064) and their zinc(II) complexes

Synergy of experimental and computational chemistry: structure and biological activity of Zn(II) hydrazone complexes

In this paper, three different Zn(II) complexes with (E)-2-(2-(1-(6-bromopyridin-2-yl)ethylidene)hydrazinyl)-N,N,N-trimethyl-2-oxoethan-1-aminium chloride (HLCl) have been synthesized and characterized by single crystal X-ray diffraction, elemental analysis, IR and NMR spectroscopy. All complexes are mononuclear, with the ligand (L) coordinated in a deprotonated formally neutral zwitterionic form via NNO donor set atoms. Complex 1 forms an octahedral geometry with the composition [ZnL2](BF4)2, while complexes 2 [ZnL(NCO)2] and 3 [ZnL(N3)2] form penta-coordinated geometry. Density functional theory (DFT) calculations were performed to enhance our understanding of the structures of the synthesized complexes and the cytotoxic activity of the complexes was tested against five human cancer cell lines (HeLa, A549, MDA-MB-231, K562, LS 174T) and normal human fibroblasts MRC-5. Additionally, antibacterial and antifungal activity of these complexes was tested against a panel of Gram-negative and Gram-positive bacteria, two fungal strains, and a yeast strain. It is noteworthy that all three complexes show selective antifungal activity comparable to that of amphotericin B. Molecular docking analysis predicted that geranylgeranyl pyrophosphate synthase, an enzyme essential for sterol biosynthesis, is the most likely target for inhibition by the tested complexes.

Efficient microwave synthesis of flurbiprofen derivatives and their enhancement of efficacy in chronic inflammatory pain models and gastro-protective potential in post-operative model

Present research was designed to synthesize and characterize the flurbiprofen derivatives and to evaluate their analgesic, anti-inflammatory and gastro-protective activities in post-operative and chronic inflammatory pain models. Flurbiprofen derivatives were produced by using three-step processes involving esterification, hydrazide production, and schiff base, each of which modified a different carboxyl group. All the newly synthesized flurbiprofen derivatives (NS5-NS8) were characterized by 1H NMR,13C NMR,19F NMR and HR-ESI-MS, and the post-operative, inflammatory pain and ulcerogenic activities were determined in well-established in-vivo animal models. To evaluate post-operative and inflammatory pain, various doses of compounds [1, 3, 10, and 30 mg/kg (bwt)] were used, while their ulcerogenic potential was assessed at doses of 100 and 150 mg/kg (bwt). The incisional damage linked pain was significantly (p < 0.001) reduced by derivatives at different doses in both the acute and repeated tests with decreased response of phologistic agent-induced inflammation. The stomach histology and biochemical features demonstrate that the synthesized derivatives have no potential to cause ulcerogenicity as compared to aspirin and flurbiprofen. Furthermore, docking shows that the hydrazide moiety of these compounds is crucial in interacting within COX-2 binding site. Therefore, the synthesized compounds exhibit strong analgesic and anti-inflammatory effects and a low risk of causing ulcers. These attributes render them potentially valuable therapeutic agents for the treatment of pathological disorders associated with inflammation and pain.Communicated by Ramaswamy H. Sarma.

Bio-oriented synthesis of ibuprofen derivatives for enhancement efficacy in post-operative and chronic inflammatory pain models

The discovery of post-operative, chronic inflammatory pain and any gastroulcerogenic potential using well-established animal models in vivo with new structures, high efficiency, broad-spectrum, and low toxicity has been the focus of medicinal chemists. In the present article, we are reporting the design and synthesis of various derivatives of ibuprofen by modifying the carboxyl group of ibuprofen using three steps reactions; esterification under microwave-irradiation in 10 minutes, hydrazide formation, and finally schiff's base reaction. Microwave-assisted esterification reaction can be employed to quickly explore and increase molecular diversity in synthetic chemistry. All of the newly synthesized compounds (NS1-NS4) were characterized by ¹H-, ¹³C-NMR, and HR-ESI-MS spectroscopy and evaluated for post-operative, chronic inflammatory pain and any gastroulcerogenic potential using well-established animal models in vivo. The synthesized compounds at the tested doses of 100 and 150 mg kg^-1 significantly attenuated the incisional-injury induced post-operative pain like condition and, also inhibited the phologistic agent induced inflammatory responses in both the acute and chronic testing paradigms. The gastric histological and biochemical parameters exhibited that the synthesized compounds were devoid of any ulcerogenic potential in comparison to aspirin and ibuprofen. These findings concluded that the synthesized ibuprofen derivatives exhibited profound analgesic, anti-inflammatory properties with reduced ulcerogenic potential and might be considered as effective therapeutic agents to treat pathological conditions associated with pain and inflammation.

In Vitro Anticancer Screening, Molecular Docking and Antimicrobial Studies of Triazole-Based Nickel(II) Metal Complexes

Herein we describe the synthesis of a series of nickel(II) complexes (C1–C3) with Schiff bases (HL1–HL3) derived from 4-amino-5-mercapto-3-methyl-1,2,4-triazole and ortho/meta/para-nitrobenzaldehyde having composition [Ni(L)₂(H₂O)₂]. The obtained ligands and their complexes were characterized using physico-chemical techniques viz., elemental analysis, magnetic moment study, spectral (electronic, FT-IR, 1H-NMR) and thermal analysis. The elemental analysis and spectral analysis revealed that Schiff bases behave as monoanionic bidentate ligands towards the Ni(II) ion. Whereas, the magnetic moment study suggested the octahedral geometry of all the Ni(II) complexes. The thermal behavior of the complexes has been studied by thermogravimetric analysis and agrees well with the composition of complexes. Further, the biological activities such as antimicrobial and antifungal studies of the Schiff bases and Ni(II) complexes have been screened against bacterial species (Staphylococcus aureus and Pseudomonas aeruginosa) and fungal species (Aspergillus niger and Candida albicans) activity by MIC method, the results of which revealed that metal complexes exhibited significant antimicrobial activities than their respective ligands against the tested microbial species. Furthermore, the molecular docking technique was employed to investigate the active sites of the selected protein, which indeed helped us to screen the potential anticancer agents among the synthesized ligand and complexes. Further, these compounds have been screened for their in vitro anticancer activity using OVCAR-3 cell line. The results revealed that the complexes are more active than the ligands.

Synthesis, characterization, antimicrobial and cytotoxic activity and DNA-binding properties of d-metal complexes with hydrazones of Girard's T and P reagents

In this work synthesis, characterization and crystal structures of 1, Zn(II) complex ([ZnL¹(NCS)₂]), with (E)-1-(2-oxo-2-(2-(quinolin-2-ylmethylene)hydrazinyl)ethyl)pyridin-1-ium chloride (HL¹Cl) and 2, Bi(III) complex ([BiHL²Cl₄] × 1/2CH₃OH), with (E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(thiazol-2-yl)ethylidene)hydrazinyl)ethan-1-aminium chloride (HL²Cl), have been reported. Zn(II) complex possesses a distorted trigonal bipyramidal geometry while surroundings around Bi(III) ion are extended pentagonal bipyramidal. Antimicrobial activity, brine shrimp assay and DPPH radical scavenging activity of both complexes, including previously synthesized complexes with HL²Cl ligand (Zn(II) and Ni(II)) and complexes with (E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)ethan-1-aminium chloride (HL³Cl) (Zn(II), Cu(II), Cd(II), Co(II), Fe(III), Ni(II)), were evaluated. For the most active complexes, cytotoxic activity against five malignant cancer cell lines (HeLa, A375, MCF7, PC-3 and A549) and normal cell line HaCaT, as well as generation of reactive oxygen species (ROS), was tested.

Synthesis of New Hydrazone Derivatives and Evaluation of their Efficacy as Proliferation Inhibitors in Human Cancer Cells

BACKGROUND

Hydrazine-hydrazones represent a group of bioactive compounds that display antibacterial, anti-inflammatory, antiviral or anticancer activities.

OBJECTIVE

In this study, we designed new derivative compounds from groups of hydrazones.

METHODS

The group of new derivatives was evaluated by the viability assay in human cancer and normal cells.

RESULTS

The dimethylpyridine hydrazones showed potent inhibition of cell proliferation of breast, colon cancer cells, human melanoma and glioblastoma. Compound 12 inhibited proliferation of cancer cells exhibiting a drug-resistant phenotype (MCF-7/DX and LoVoDX) at low millimolar concentrations. Whereas, antimelanoma activity was revealed by Compounds 2, 4, 7 and 12.

CONCLUSION

The present results highlighted newly synthetized hydrazine derivatives an excellent base for the design of new anticancer agents and resistance inhibitors.

Ni(II) Complexes with Schiff Base Ligands: Preparation, Characterization, DNA/Protein Interaction and Cytotoxicity Studies

In this study, two Ni(II) complexes, namely [Ni(HL1)₂(OAc)₂] (1) and [Ni(L2)₂] (2) (where HL1 and HL2 are (E)-1-((1-(2-hydroxyethyl)-1H-pyrazol-5-ylimino)methyl)-naphthalen-2-ol) and (E)-ethyl-5-((2-hydroxynaphthalen-1-yl)methyleneamino)-1-methyl-1H-pyrazole-4-carboxylate, respectively), were synthesized and characterized by X-ray crystallography, Electrospray Ionization Mass Spectrometry (ESI-MS), elemental analysis, and IR. Their uptake in biological macromolecules and cancer cells were preliminarily investigated through electronic absorption (UV-Vis), circular dichroism (CD) and fluorescence quenching measurements. Bovine serum albumin (BSA) interaction experiments were investigated by spectroscopy which showed that the complexes and ligands could quench the intrinsic fluorescence of BSA through an obvious static quenching process. The spectroscopic studies indicated that these complexes could bind to DNA via groove, non-covalent, and electrostatic interactions. Furthermore, in vitro methyl thiazolyl tetrazolium (MTT) assays and Annexin V/PI flow cytometry experiments were performed to assess the antitumor capacity of the complexes against eight cell lines. The results show that both of the complexes possess reasonable cytotoxicities.

A porphyrin-based fluorescence method for zinc determination in commercial propolis extracts without sample pretreatment

The quantification of zinc in over-the-counter drugs as commercial propolis extracts by molecular fluorescence technique using meso-tetrakis(4-carboxyphenyl)porphyrin (H₂ TCPP⁴ ) was developed for the first time. The calibration curve is linear from 6.60 to 100 nmol L^-1 of Zn²⁺ . The detection and quantification limits were 6.22 nmol L^-1 and 19.0 nmol L^-1 , respectively. The reproducibility and repeatability calculated as the percentage variation of slopes of seven calibration curves were 6.75% and 4.61%, respectively. Commercial propolis extract samples from four Brazilian states were analyzed and the results (0.329-0.797 mg/100 mL) obtained with this method are in good agreement with that obtained with the Atomic Absorption Spectroscopy (AAS) technique. The method is simple, fast, of low cost and allows the analysis of the samples without pretreatment. Moreover the major advantage is that Zn-porphyrin complex presents fluorescent characteristic promoting the selectivity and sensitivity of the method.

Synthesis, characterization of 1,2,4-triazole Schiff base derived 3d-metal complexes: Induces cytotoxicity in HepG2, MCF-7 cell line, BSA binding fluorescence and DFT study

Two novel Schiff base ligands H₂L¹ and H₂L² have been synthesized by condensation reaction of amine derivative of 1,2,4-triazole moiety with 2-hydroxy-4-methoxybenzaldehyde. Co(II), Ni(II), Cu(II) and Zn(II) of the synthesized Schiff bases were prepared by using a molar ratio of ligand:metal as 1:1. The structure of the Schiff bases and synthesized metal complexes were established by ¹H NMR, UV-Vis, IR, Mass spectrometry and molar conductivity. The thermal stability of the complexes was study by TGA. Fluorescence quenching mechanism of metal complexes 1-4 show that Zn(II) and Cu(II) complex binds more strongly to BSA. In DFT studies the geometries of Schiff bases and metal complexes were fully optimized with respect to the energy using the 6-31+g(d,p) basis set. The spectral data shows that the ligands behaves as binegative tridentate. On the basis of the spectral studies, TGA and DFT data an octahedral geometry has been assigned for Co(II), Ni(II), square planar for Cu(II) and tetrahedral for Zn(II) complexes. The anticancer activity were screened against human breast cancer cell line (MCF-7) and human hepatocellular liver carcinoma cell line (Hep-G2). Result indicates that metal complexes shows increase cytotoxicity in proliferation to cell lines as compared to free ligand.

3-methoxy aroylhydrazones - free radicals scavenging, anticancer and cytoprotective potency

OBJECTIVE

This study aimed to determine the capability of newly designed 3-methoxy derivatives of salicylaldehyde benzoylhydrazone to influence the oxidative stress processes and to test their in vitro cytotoxicity.

METHODS

We have used chemiluminescent and spectrophotometric model systems containing different types of reactive oxygen species (OH^●, OCl^─ and O₂^─●). The hydrazones effect on the viability of Hep-G2, HEK-293 and SH-SY5Y cell lines was determined via MTT assay.

RESULTS

The comparative analysis of the C₅₀ values of the chemiluminescent investigation demonstrated moderate activity against the hydroxyl radicals (C₅₀ > 50 μmol/L) and remarkable reactivity in the systems containing a superoxide radical and a hypochlorous anion (C₅₀ < 3.7 μmol/L). Further experiments in the spectrophotometric system of UV-induced OH^● generation and consequent 2'-deoxyribose oxidative damage excluded the possibility of quenching effect and proved the direct interaction of the studied compounds with that generated in the system reactive oxygen species (ROS). The encapsulation of the studied derivatives into chitosan-alginate particles led to the protection and stabilization of their antioxidant activity as revealed by a one-month study using the ABTS ^●+ method. The cytotoxic study revealed less pronounced effects against the non-malignant cell line (HEK-293) compared to Hep-G2 and SH-SY-5Y cells.

DISCUSSION

The incorporation of a hydroxyl group in the hydrazide part of a parent molecule which relates to better antioxidant effect in most of the studied systems is associated with higher IC₅₀ values in all cytotoxicity experiments and relates to the cytoprotective effect against N-methyl-D-aspartate-induced excitotoxicity in SH-SY5Y human neuronal cells.

Synthesis, characterization, DNA binding, cleavage activity, cytotoxicity and molecular docking of new nano water-soluble [M(5-CH₂PPh₃-3,4-salpyr)](ClO₄)₂ (M = Ni, Zn) complexes

Some new water soluble complexes [N,N'-bis{5-[(triphenyl phosphonium chloride)-methyl]salicylidine}-3,4-diaminopyridine] M(ii), which are formulated as nano-[Zn(5-CH2PPh3-3,4-salpyr)](ClO4)2 (), [Zn(5-CH2PPh3-3,4-salpyr)](ClO4)2 (), nano-[Ni(5-CH2PPh3-3,4-salpyr)](ClO4)2 (), [Ni(5-CH2PPh3-3,4-salpyr)](ClO4)2 (), and [N,N'-bis{5-[(triphenyl phosphonium chloride)-methyl]salicylidine}-2,3-diaminopyridine]Ni(ii) [Ni(5-CH2PPh3-2,3-salpyr)](ClO4)2 () have been isolated and characterized by elemental analysis, FT-IR, (1)H NMR, (13)C NMR, (31)P NMR, and UV-vis spectroscopy. The morphology and size of the nano complexes were determined using FE-SEM and TEM. In vitro DNA binding studies were investigated by UV-vis absorption spectroscopy, viscosity measurements, CD spectroscopy, cyclic voltammetry, emission spectra and gel electrophoresis, which suggest that the metal complexes act as efficient DNA binders. The absorption spectroscopy of the compounds with DNA reveals that the DNA binding affinity (Kb) has this order: > > > > > Ligand. The metal complexes show DNA binding stronger than the ligand, which is expected due to the nature of the metal. The nano complexes display DNA binding stronger than the other complexes which is related to the effect of size on binding affinity and the Ni(ii) complexes reveal DNA binding stronger than the corresponding Zn(ii) analogues, which is expected due to their z* effect and geometry. The prominent double strand DNA cleavage abilities of compound are observed in the absence of H2O2 with efficiencies of more than 50% even at 70 μM complex concentration. Surprisingly, Zn(ii) complexes (compounds & ) exhibit a higher cytotoxicity (IC50: 7.3 & 10.9 μM at 24 h; IC50: 4.6 & 8.7 μM at 48 h) against human hepatoma (HepG2) and HeLa cell lines than the Ni(ii) complexes (compounds , & ) and 5-fluorouracil as control in spite of their inability to cleave DNA. Finally, DNA binding interactions were performed by docking studies. Density functional theory (DFT) studies were performed using the GAUSSIAN 03 program. The DFT method with B3LYP functional, LANL2DZ basis set for metal centers and 6-311g* for other atoms was used. The synthesized compounds and DNA were simulated by molecular docking to explore more details of the ligands conformation and their orientations in the active site of the receptor.

Bismuth(III) complexes with 2-acetylpyridine- and 2-benzoylpyridine-derived hydrazones: Antimicrobial and cytotoxic activities and effects on the clonogenic survival of human solid tumor cells

Complexes [Bi(2AcPh)Cl2]·0.5H2O (1), [Bi(2AcpClPh)Cl2] (2), [Bi(2AcpNO2Ph)Cl2] (3), [Bi(2AcpOHPh)Cl2]·2H2O (4), [Bi(H2BzPh)Cl3]·2H2O (5), [Bi(H2BzpClPh)Cl3] (6), [Bi(2BzpNO2Ph)Cl2]·2H2O (7) and [Bi(H2BzpOHPh)Cl3]·2H2O (8) were obtained with 2-acetylpyridine phenylhydrazone (H2AcPh), its -para-chloro-phenyl- (H2AcpClPh), -para-nitro-phenyl (H2AcpNO2Ph) and -para-hydroxy-phenyl (H2AcpOHPh) derivatives, as well as with the 2-benzoylpyridine phenylhydrazone analogues (H2BzPh, H2BzpClPh, H2BzpNO2Ph, H2BzpOHPh). Upon coordination to bismuth(III) antibacterial activity against Gram-positive and Gram-negative bacterial strains significantly improved except for complex (4). The cytotoxic effects of the compounds under study were evaluated on HL-60, Jurkat and THP-1 leukemia, and on MCF-7 and HCT-116 solid tumor cells, as well as on non-malignant Vero cells. In general, 2-acetylpyridine-derived hydrazones proved to be more potent and more selective as cytotoxic agents than the corresponding 2-benzoylpyridine-derived counterparts. Exposure of HCT-116 cells to H2AcpClPh, H2AcpNO2Ph and complex (3) led to 99% decrease of the clonogenic survival. The IC50 values of these compounds were three-fold smaller when cells were cultured in soft-agar (3D) than when cells were cultured in monolayer (2D), suggesting that they constitute interesting scaffolds, which should be considered in further studies aiming to develop new drug candidates for the treatment of colon cancer.

Coordination behavior of new bis Schiff base ligand derived from 2-furan carboxaldehyde and propane-1,3-diamine. Spectroscopic, thermal, anticancer and antibacterial activity studies

Novel bis Schiff base ligand, [N1,N3-bis(furan-2-ylmethylene)propane-1,3-diamine], was prepared by the condensation of furan-2-carboxaldehyde with propane-1,3-diamine. Its conformational changes on complexation with transition metal ions [Co(II), Ni(II), Cu(II), Mn(II), Cd(II), Zn(II) and Fe(III)] have been studied on the basis of elemental analysis, conductivity measurements, spectral (infrared, (1)H NMR, electronic), magnetic and thermogravimetric studies. The conductance data of the complexes revealed their electrolytic nature suggesting them as 1:2 (for bivalent metal ions) and 1:3 (for Fe(III) ion) electrolytes. The complexes were found to have octahedral geometry based on magnetic moment and solid reflectance measurements. Thermal analysis data revealed the decomposition of the complexes in successive steps with the removal of anions, coordinated water and bis Schiff base ligand. The thermodynamic parameters were calculated using Coats-Redfern equation. The Anticancer screening studies were performed on human colorectal cancer (HCT), hepatic cancer (HepG2) and breast cancer (MCF-7) cell lines. The antimicrobial activity of all the compounds was studied against Gram negative (Escherichia coli and Proteus vulgaris) and Gram positive (Bacillus vulgaris and Staphylococcus pyogones) bacteria. It was observed that the coordination of metal ion has a pronounced effect on the microbial activities of the bis Schiff base ligand. All the metal complexes have shown higher antimicrobial effect than the free bis Schiff base ligand.

Azine or hydrazone? The dilemma in amidinohydrazones

Amidinohydrazone, an important class of biologically active molecules, is generally represented as a hydrazone. This moiety prefers to exist in its azine tautomeric state and hence, influences the physical, chemical and receptor binding properties.

Influence of the diversified structural variations at the imine functionality of 4-bromophenylacetic acid derived hydrazones on alkaline phosphatase inhibition: synthesis and molecular modelling studies

Putative binding mode of 4g inside the active pocket of h-PLAP.

Metal complexes as potential modulators of inflammatory and autoimmune responses

In this perspective, we highlight recent examples in the development of transition metal complexes as modulators of inflammatory and autoimmune responses.

Over the past few decades, the realm of inorganic medicinal chemistry has been dominated by the study of the anti-cancer properties of transition metal complexes, particularly those based on platinum or ruthenium. However, comparatively less attention has been focused on the development of metal complexes for the treatment of inflammatory or autoimmune diseases. Metal complexes possess a number of advantages that render them as attractive alternatives to organic small molecules for the development of therapeutic agents. In this perspective, we highlight recent examples in the development of transition metal complexes as modulators of inflammatory and autoimmune responses. The studies presented here serve to highlight the potential of transition metal complexes in modulating inflammatory or immune pathways in cells.

Differential regulation of ASICs and TRPV1 by zinc in rat bronchopulmonary sensory neurons

PURPOSE

Zinc has been known to act as a signaling molecule that regulates a variety of neuronal functions. In this study, we aimed to study the effect of zinc on two populations of acid-sensitive ion channels, acid-sensing ion channels (ASICs), and transient receptor potential vanilloid receptor-1 (TRPV1), in vagal bronchopulmonary sensory neurons.

METHODS

Rat vagal sensory neurons innervating lungs and airways were retrogradely labeled with a fluorescent tracer. Whole-cell perforated patch-clamp recordings were carried out in primarily cultured bronchopulmonary sensory neurons. The acid-evoked ASIC and TRPV1 currents were measured and compared between before and after the zinc pretreatment.

RESULTS

ASIC currents were induced by a pH drop from 7.4 to 6.8 or 6.5 in the presence of capsazepine (10 µM), a specific TRPV1 antagonist. Pretreatment with zinc (50 or 300 µM, 2 min) displayed different effects on the two distinct phenotypes of ASIC currents: a marked potentiation on ASIC channels with fast kinetics of activation and inactivation or no significant effect on ASIC currents with slow activation and inactivation. On the other hand, pretreatment with zinc significantly inhibited the acid (pH 5.5 or 5.3)-induced TRPV1 currents. The inhibition was abolished by intracellular chelation of zinc by TPEN (25 µM), indicating that intracellular accumulation of zinc was likely required for its inhibitory effect on TRPV1 channels.

CONCLUSIONS

Our study showed that zinc differentially regulates the activities of ASICs and TRPV1 channels in rat vagal bronchopulmonary sensory neurons.

Analgesic and anti-inflammatory activity of 7-substituted purine-2,6-diones

BACKGROUND

In an effort to develop new analgesic and anti-inflammatory agents, we determined a series of 7-substituted purine-2,6-diones.

METHODS

The obtained compounds (1-6) were evaluated pharmacologically in four in vivo models: the writhing syndrome, the formalin tests, the carrageenan-induced edema model and the zymosan-induced peritonitis. The influence of the investigated compounds on the phosphodiesterase (PDE) and PDE4B activity was also determined. In addition, determination of the antioxidant activity was determined by the FRAP assay.

RESULTS

A majority of the tested compounds showed a significant analgesic and anti-inflammatory activity. The strongest analgesic and anti-inflammatory effect was observed for 1 and 2. The active compound 1 was more efficient than theophylline in inhibiting the PDE and more efficient than rolipram in inhibiting the PDE4B activity. The tested compounds did not show significant antioxidant properties.

CONCLUSION

Active compounds (1-6) inhibited the PDE activity, while compound 1 significantly inhibited the PDE4B activity, what may suggest that this mechanism may be involved in their analgesic/anti-inflammatory properties.

Therapeutic potential of hydrazones as anti-inflammatory agents

Hydrazones are a special class of organic compounds in the Schiff base family. Hydrazones constitute a versatile compound of organic class having basic structure (R₁R₂C=NNR₃R₄). The active centers of hydrazone, that is, carbon and nitrogen, are mainly responsible for the physical and chemical properties of the hydrazones and, due to the reactivity toward electrophiles and nucleophiles, hydrazones are used for the synthesis of organic compound such as heterocyclic compounds with a variety of biological activities. Hydrazones and their derivatives are known to exhibit a wide range of interesting biological activities like antioxidant, anti-inflammatory, anticonvulsant, analgesic, antimicrobial, anticancer, antiprotozoal, antioxidant, antiparasitic, antiplatelet, cardioprotective, anthelmintic, antidiabetic, antitubercular, trypanocidal, anti-HIV, and so forth. The present review summarizes the efficiency of hydrazones as potent anti-inflammatory agents.

Synthesis and X-ray structure of a new zinc(ii) coordination polymer: interaction with DNA and double stranded RNA and elucidation of the molecular aspects of the binding to bovine serum albumin

Synthesis and characterization of [Zn(4-Me-5-CHOIm)₂(HCOO)](ClO₄) complex and binding with nucleic acids and BSA has been explored by different biophysical techniques with the combination of isothermal titration calorimetry (ITC).

Zn(II)-Chlorido complexes of phytohormone kinetin and its derivatives modulate expression of inflammatory mediators in THP-1 cells

Kinetin (N6-furfuryladenine) belongs to a group of plant growth hormones involved in cell division, differentiation and other physiological processes. One of the possible ways to obtain biologically active compounds is to complex biologically relevant natural compounds to suitable metal atoms. In this work, two structural groups of Zn(II) complexes [Zn(Lⁿ)₂Cl₂]·Solv (1–5) and [Zn(HLⁿ)Cl₃]·xLⁿ (6–7); n = 1–5, Solv = CH₃OH for 1 and 2H₂O for 2; x = 1 for 6 and 2 for 7; involving a phytohormone kinetin and its derivatives (Lⁿ) were evaluated for their ability to modulate secretion of tumour necrosis factor (TNF)-α, interleukin (IL)-1β and matrix metalloproteinase (MMP)-2 in a lipopolysaccharide (LPS)-activated macrophage-like THP-1 cell model. The penetration of the complexes to cells was also detected. The mechanism of interactions of the zinc(II) complexes with a fluorescent sensor N-(6-methoxy-8-quinolyl)-p-toluene sulphonamide (TSQ) and sulfur-containing biomolecules (l-cysteine and reduced glutathione) was studied by electrospray-ionization mass spectrometry and flow-injection analysis with fluorescence detection. The present study showed that the tested complexes exhibited a low cytotoxic effect on the THP-1 cell line (IC₅₀>40 µM), apart from complex 4, with an IC₅₀ = 10.9±1.1 µM. Regarding the inflammation-related processes, the Zn(II) complexes significantly decreased IL-1β production by a factor of 1.47–2.22 compared with the control (DMSO), but did not affect TNF-α and MMP-2 secretions. However, application of the Zn(II) complexes noticeably changed the pro-MMP-2/MMP-2 ratio towards a higher amount of maturated MMP-2, when they induced a 4-times higher production of maturated MMP-2 in comparison with the vehicle-treated cells under LPS stimulation. These results indicated that the complexes are able to modulate an inflammatory response by influencing secretion and activity of several inflammation-related cytokines and enzymes.

Inhibition of human acid-sensing ion channel 1b by zinc

Acid-sensing ion channel 1b (ASIC1b) is expressed in peripheral sensory neurons and has been implicated in nociception. Understanding the modulation of ASIC1b will provide important insight into how ASIC1b contributes to pain sensation. In our previous study, we showed that zinc, an important modulator of pain sensation, reduces rat ASIC1b current. However, rat ASIC1b shows several important differences from its recently identified human homolog. Most noticeably, human ASIC1b (hASIC1b) has a sustained component, which may play a role in persistent pain. Therefore, we tested here the hypothesis that zinc modulates the current properties of hASIC1b. Bath application of zinc suppressed the peak amplitude of hASIC1b currents, with a half-maximum inhibitory concentration of 37 μM. However, zinc did not affect the sustained component of hASIC1b currents. The effect of zinc was independent of pH-dependent activation, steady-state desensitization, and extracellular Ca(2+), suggesting noncompetitive mechanisms. Further, we found that extracellular site(s) of the hASIC1b subunit is important for the effect of zinc. Mutating cysteine 196, but not cysteine 309, in the extracellular domain of the hASIC1b abolished the zinc inhibition. These results suggest that, through modulating cysteine196, zinc may have a modulatory role in acute pain.