ascorbic-acid and 7-hydroxycoumarin

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.

Topics: Acetylcholinesterase; Animals; Butyrylcholinesterase; Cell Death; Cholinesterase Inhibitors; Dose-Response Relationship, Drug; Electrophorus; Horses; Hydrogen Peroxide; Models, Molecular; Molecular Structure; PC12 Cells; Rats; Structure-Activity Relationship; Umbelliferones

The antigenotoxic effects of umbelliferone (UMB), herniarin (HER) and 7-isopentenyloxy coumarin (7-IP), common natural dietary coumarins, were evaluated on the human lymphocyte DNA damage using single-cell gel electrophoresis. H(2)O(2)-induced DNA break was measured based on the percentage of DNA in tail, and the antigenotoxic effects of the tested compounds were compared with that of ascorbic acid (10, 25, 50, 100 and 200 μM). UMB, HER and 7-IP did not show any genotoxicity, as compared to phosphate-buffered saline. Treatment with UMB, HER and 7-IP led to a significant reduction in the percentage of DNA in tail induced by H(2)O(2) (p < 0.001) at all concentrations. The presence of prenyl moiety in the chemical structure of 7-IP may contribute to its better antigenotoxic property, compared to UMB. The results of this study showed that 7-IP possessed the best antigenotoxic activity among the tested compounds.

Topics: Adult; Antimutagenic Agents; Ascorbic Acid; Comet Assay; Coumarins; DNA Damage; Dose-Response Relationship, Drug; Humans; Hydrogen Peroxide; Lymphocytes; Oxidative Stress; Umbelliferones

In this study, we systematically investigate the mechanism of single-layer MnO2 nanosheets suppressing fluorescence of 7-hydroxycoumarin and, based on this, demonstrate a new fluorescent method for in vivo sensing of ascorbic acid (AA) in rat brain. The mechanism for the fluorescence suppression is attributed to a combination of inner filter effect (IFE) and static quenching effect (SQE), which is different from those reported for the traditional two-dimensional nanosheets, and Förster resonant energy transfer (FRET) mechanism reported for MnO2 nanosheets. The combination of IFE and SQE leads to an exponential decay in fluorescence intensity of 7-hydroxycoumarin with increasing concentration of MnO2 nanosheets in solution. Such a property allows optimization of the concentration of MnO2 nanosheets in such a way that the addition of reductive analyte (e.g., AA) will to the greatest extent restore the MnO2 nanosheets-suppressed fluorescence of 7-hydroxycoumarin through the redox reaction between AA and MnO2 nanosheets. On the basis of this feature, we demonstrate a fluorescent method for in vivo sensing of AA in the cerebral systems with an improved sensitivity. Compared with the turn-on fluorescent method through first decreasing the fluorescence to the lowest level by adding concentrated MnO2 nanosheets, the method demonstrated here possesses a higher sensitivity, lower limit of detection, and wider linear range. Upon the use of ascorbate oxidase to achieve the selectivity for AA, the turn-on fluorescence method demonstrated here can be used for in vivo sensing of AA in a simple but reliable way.

Topics: Animals; Ascorbic Acid; Brain; Limit of Detection; Male; Manganese Compounds; Nanostructures; Oxides; Rats; Rats, Sprague-Dawley; Spectrometry, Fluorescence; Umbelliferones

The objective of the study was to investigate the role of Umbelliferone (UMB) on lipid peroxidation, nonenzymic and enzymic antioxidants in the plasma and liver of streptozotocin (STZ)-induced diabetic rats. Adult male albino rats of Wistar strain, weighing 180-200 g, were induced diabetes by administration of STZ (40 mg/kg b.wt.) intraperitoneally. The normal and diabetic rats were treated with UMB (30 mg/kg b.wt.) dissolved in 10% dimethyl sulfoxide (DMSO) for 45 days. Diabetic rats had an elevation in the levels of lipid peroxidation markers (thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides (HP) and conjugated dienes (CD)), and a reduction in nonenzymic antioxidants (vitamin C and reduced glutathione (GSH) except vitamin E in the plasma and liver, and enzymic antioxidants (superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in the liver. Decreased level of beta-carotene and increased level of ceruloplasmin (Cp) were observed in the plasma of diabetic rats. Treatment with UMB and glibenclamide brought back lipid peroxidation markers, nonenzymic and enzymic antioxidants to near normalcy. Since UMB treatment decreases lipid peroxidation markers and enhances antioxidants' status it can be considered as a potent antioxidant.

Topics: Animals; Antioxidants; Ascorbic Acid; Catalase; Diabetes Mellitus, Experimental; Glutathione; Glutathione Peroxidase; Lipid Peroxidation; Lipid Peroxides; Liver; Male; Rats; Rats, Wistar; Streptozocin; Superoxide Dismutase; Thiobarbituric Acid Reactive Substances; Umbelliferones; Vitamin E