Antinociceptive properties of new coumarin derivatives bearing substituted 3,4-dihydro-2H-benzothiazines.

BACKGROUND: Coumarins are an important class of widely distributed heterocyclic natural products exhibiting a broad pharmacological profile. In this work, a new series of coumarins bearing substituted 3,4-dihydro-2H-benzothiazines were described as potential analgesic agents. The clinical use of NSAIDs as traditional analgesics is associated with side effects such as gastrointestinal lesions and nephrotoxicity. Therefore, the discovery of new safer drugs represents a challenging goal for such a research area. RESULTS: The target compounds 3-(3-methyl-3,4-dihydro-2H-benzo[b][1,4]thiazin-3-yl)-2H-chromen-2-ones 2a-u were synthesized and characterized by spectral data. The antinociceptive properties of target compounds were determined by formalin-induced test and acetic acid-induced writhing test in mice. Among the tested compounds, compound 2u bearing 2-(4-(methylsulfonyl)benzoyl)- moiety on benzothiazine ring and 4-(methylsulfonyl)phenacyloxy- group on the 7 position of coumarin nucleus showed better profile of antinocecieption in both models. It was more effective than mefenamic acid during the late phase of formalin-induced test as well as in the acetic acid-induced writhing test. CONCLUSION: Considering the significant antinoceciptive action of phenacyloxycoumarin derivatives, compound 2u prototype might be further used as model to obtain new more potent analgesic drugs.

Synthesis of some new 3-coumaranone and coumarin derivatives as dual inhibitors of acetyl- and butyrylcholinesterase.

A novel series of coumarin and 3-coumaranone derivatives encompassing the phenacyl pyridinium moiety were synthesized and evaluated for their acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activity using Ellman's method. All compounds presented inhibitory activity against both AChE and BuChE in the micromolar range. The molecular docking simulations revealed that all compounds were dual binding site inhibitors of AChE. A kinetic study was performed and the mechanism of enzyme inhibition was proved to be of mixed type. All compounds were tested for their antioxidant activity and no significant activity was observed.

Novel coumarin derivatives bearing N-benzyl pyridinium moiety: potent and dual binding site acetylcholinesterase inhibitors.

A novel series of coumarin derivatives linked to benzyl pyridinium group were synthesized and biologically evaluated as inhibitors of both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). The enzyme inhibitory activity of synthesized compounds was measured using colorimetric Ellman's method. It was revealed that compounds 3e, 3h, 3l, 3r and 3s have shown higher activity compared with donepezil hydrochloride as standard drug. Most of the compounds in these series had nanomolar range IC(50) in which compound 3r (IC(50) = 0.11 nM) was the most active compound against acetylcholinesterase enzyme.

Glutathione conjugated polyethylenimine on the surface of Fe3O4 magnetic nanoparticles as a theranostic agent for targeted and controlled curcumin delivery.

Theranostics with the ability to simultaneous monitoring of treatment progress and controlled delivery of therapeutic agents has become as an emerging therapeutic paradigm in cancer therapy. In this study, we have developed a novel surface functionalized iron oxide nanoparticle using polyethyleneimine and glutathione for targeted curcumin (CUR) delivery and acceptable pH sensitive character. The developed magnetic nanoparticles (MNPs) were physicochemically characterized by FT-IR, XRD, FE-SEM and TEM. The MNPs was obtained in spherical shape with diameter of 50 nm. CUR was efficiently loaded into the MNPs and then in vitro release analyses were evaluated and showed that the prepared MNPs could release higher amount of CUR in acidic medium compared to neutral medium due to the pH sensitive property of the coated polymer. MTT assay confirmed the superior toxicity of CUR loaded MNPs compared to the control nanoparticles. Higher cellular uptake of the MNPs than negative control cells was demonstrated in SK-N-MC cell line. In vitro assessment of MRI properties showed that synthesized MNPs could be used as MRI imaging agent. Furthermore, according to hemolysis assay, the developed formulation exhibited suitable hemocompatibility. In vivo blood circulation analysis of the MNPs also exhibited enhanced serum bioavailability up to 2.5 fold for CUR loaded MNPs compared with free CUR.

Impact of Kidney Transplantation on Biomarkers of Oxidative Stress and Inflammation.

INTRODUCTION: Hemodialysis patients face oxidative stress and inflammation induced by both kidney dysfunction and hemodialysis procedure. These are supposed to be partly responsible for the excessive cardiovascular morbidity and mortality in hemodialysis patients. We investigated the impact of kidney transplantation on the biomarkers of oxidative stress and inflammation. MATERIALS AND METHODS: In a prospective cohort study on 32 kidney transplant candidates on hemodialysis, biomarkers of oxidative stress and inflammation were compared before and 3 months after kidney transplantation and were compared with each other as well as their values in the kidney allograft donors as the controls. These biomarkers included total antioxidant capacity, total thiol molecules, lipid peroxidation, plasma catalase, superoxide dismutase, glutathione peroxidase, and C-reactive protein. RESULTS: The mean age of the patients was 38.0 ± 15.5 years. The levels of total antioxidant capacity, total thiol molecules, and activity of glutathione peroxidase were significantly lower and the level of activity of plasma superoxide dismutase was significantly higher in the hemodialysis patients before transplantation as compared to the values for the controls and after transplantation. Lipid peroxidation was significantly higher in the patients before transplantation compared to the controls. A significantly higher level of C-reactive protein was noted in the hemodialysis patients as compared to their levels after transplantation and also C-reactive protein in the controls. CONCLUSIONS: These results suggest that oxidative stress and inflammation are elevated in hemodialysis patients which could be improved partly and significantly by restoration of kidney function after kidney transplantation.

Synthesis and anti-cholinesterase activity of new 7-hydroxycoumarin derivatives.

A series of 7-hydroxycoumarin derivatives connected by an amidic linker to the different amines were designed and synthesized as cholinesterase inhibitors. Most compounds showed remarkable inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Among them, N-(1-benzylpiperidin-4-yl)acetamide derivative 4r with IC50 value of 1.6 µM was the most potent compound against AChE. The selectivity index of compound 4r for anti-AChE activity was about 26. Moreover, the compound 4r significantly protected PC12 neurons against H2O2-induced cell death at low concentrations. The docking study of compound 4r with AChE enzyme showed that both CAS and PAS are occupied by the ligand.

Polyoxygenated cinnamoylcoumarins as conformationally constrained analogs of cytotoxic diarylpentanoids: synthesis and biological activity.

A series of polyoxygenated cinnamoylcoumarins was synthesized as conformationally constrained analogs of cytotoxic diarylpentanoids. The title compounds were tested against the viability of human chronic myelogenous leukemia (K562), human acute lymphoblastic leukemia (MOLT-4) and human breast adenocarcinoma (MCF-7) cell lines by using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Among them, all 6- or 7-hydroxylated compounds 6a-h exhibited remarkable cytotoxic activity. Particularly, 7-hydroxycoumarin analog 6h showed good antiproliferative activity against all tested cell lines (IC50 values≤5.5 µM). The preliminary study with selected compounds 6e and 6f showed that reactivity towards mitochondrial thiol compounds cab be considered as cytotoxic mechanism of designed compounds. Furthermore, the antioxidant activity evaluation of synthesized compounds showed that hydroxylated compounds had antioxidative potential at higher concentrations.

Design, synthesis, biological evaluation and docking study of 5-oxo-4,5-dihydropyrano[3,2-c]chromene derivatives as acetylcholinesterase and butyrylcholinesterase inhibitors.

A series of fused coumarins namely 5-oxo-4,5-dihydropyrano[3,2-c]chromenes linked to N-benzylpyridinium scaffold were synthesized and evaluated as acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitors. The 1-(4-fluorobenzyl)pyridinium derivative 6g showed the most potent anti-AChE activity (IC50 value=0.038 µM) and the highest AChE/BuChE selectivity (SI>48). The docking study permitted us to rationalize the observed structure-affinity relationships and to detect possible binding modes.

Design, synthesis, docking study and biological evaluation of some novel tetrahydrochromeno [3',4':5,6]pyrano[2,3-b]quinolin-6(7H)-one derivatives against acetyl- and butyrylcholinesterase.

Novel hybrid derivatives of two known scaffolds; tetrahydroaminoquinoline and coumarin were synthesized and evaluated for both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities. By means of an efficient nanocatalyst, the reaction time for the syntheses of the target compounds was reduced. Subsequently, Ellman's modified method was used to evaluate the enzyme inhibitory activity of the synthesized structures. It was observed that most hybrid structures were moderate to potent inhibitors of AChE compared to Tacrine as the reference drug among which 7f with 4-fluorophenyl substituent was the most active compound (IC50=5 nM).

Novel coumarin-3-carboxamides bearing N-benzylpiperidine moiety as potent acetylcholinesterase inhibitors.

Some novel coumarin-3-carboxamide derivatives linked to N-benzylpiperidine scaffold were synthesized and evaluated as acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitors. The screening results showed that most of compounds exhibited potent anti-AChE activity in the range of nM concentrations. Among them, compound 10c bearing an N-ethylcarboxamide linker and a 6-nitro substituent showed the most potent activity (IC50 = 0.3 nM) and the highest selectivity (SI = 26,300). Compound 10c was 46-fold more potent than standard drug donepezil against AChE. The kinetic study revealed that compound 10c exhibited mixed-type inhibition against AChE. Protein-ligand docking study demonstrated that the target compounds have dual binding site interaction mode and these results are in agreement with kinetic study.

A facile route to flavone and neoflavone backbones via a regioselective palladium catalyzed oxidative Heck reaction.

A straightforward and atom-economical base-free palladium-catalyzed regioselective direct arylation of coumarins and chromenones is devised. This protocol is compatible with a wide variety of electron-donating and -withdrawing substituents and allows construction of various biologically important flavone and neoflavone backbones.