5 resultados para Time Dependent Effects

em Universidade Federal do Rio Grande do Norte(UFRN)


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Sulfated polysaccharides comprise a complex group of macromolecules with a range of several biological activities, including antiviral activity, anticoagulant, antiproliferative, antiherpética, antitumor, anti-inflammatory and antioxidant. These anionic polymers are widely distributed in tissues of vertebrates, invertebrates and algae. Seaweeds are the most abundant sources of sulfated polysaccharides in nature. The green algal sulfated polysaccharides are homo or heteropolysaccharides comprised of galactose, glucose, arabinose and/or glucuronic acid. They are described as anticoagulant, anti-inflammatory, antiviral, anti-angiogenic, antitumor compounds. However, there are few studies about elucidation and evaluation of biological/pharmacological effects of sulfated polysaccharides obtained from green algae, for example, there is only one paper reporting the antinociceptive activity of sulfated polysaccharides of these algae. Therefore this study aimed to obtain sulfated polysaccharides of green seaweed Codium isthmocladum and evaluates them as potential antinociceptive agents. Thus, in this study, the total extract of polysaccharides of green alga C. isthmocladum was obtained by proteolytic digestion, followed by fractionation resulting in five fractions (F0.3, F0.5, F0.7, F0.9 and F1.2) by sequential precipitation with acetone. Using the test of abdominal contractions we observed that the fraction F0.9 was the most potent antinociceptive aompound. F0.9 consists mainly of a sulfated heterogalactana. More specific tests showed that Fo.9 effect is dose and time dependent, reaching a maximum at 90 after administration (10 mg / kg of animal). F0.9 is associated with TRPV1 and TRPA1 receptors and inhibits painful sensation in animals. Furthermore, F0.9 inhibits the migration of lymphocytes induced peritonitis test. On the other hand, stimulates the release of NO and TNF-α. These results suggest that F0.9 has the potential to be used as a source of sulfated galactan antinociceptive and anti-inflammatory

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Sulfated polysaccharides comprise a complex group of macromolecules with a range of several biological activities, including antiviral activity, anticoagulant, antiproliferative, antiherpética, antitumor, anti-inflammatory and antioxidant. These anionic polymers are widely distributed in tissues of vertebrates, invertebrates and algae. Seaweeds are the most abundant sources of sulfated polysaccharides in nature. The green algal sulfated polysaccharides are homo or heteropolysaccharides comprised of galactose, glucose, arabinose and/or glucuronic acid. They are described as anticoagulant, anti-inflammatory, antiviral, anti-angiogenic, antitumor compounds. However, there are few studies about elucidation and evaluation of biological/pharmacological effects of sulfated polysaccharides obtained from green algae, for example, there is only one paper reporting the antinociceptive activity of sulfated polysaccharides of these algae. Therefore this study aimed to obtain sulfated polysaccharides of green seaweed Codium isthmocladum and evaluates them as potential antinociceptive agents. Thus, in this study, the total extract of polysaccharides of green alga C. isthmocladum was obtained by proteolytic digestion, followed by fractionation resulting in five fractions (F0.3, F0.5, F0.7, F0.9 and F1.2) by sequential precipitation with acetone. Using the test of abdominal contractions we observed that the fraction F0.9 was the most potent antinociceptive aompound. F0.9 consists mainly of a sulfated heterogalactana. More specific tests showed that Fo.9 effect is dose and time dependent, reaching a maximum at 90 after administration (10 mg / kg of animal). F0.9 is associated with TRPV1 and TRPA1 receptors and inhibits painful sensation in animals. Furthermore, F0.9 inhibits the migration of lymphocytes induced peritonitis test. On the other hand, stimulates the release of NO and TNF-α. These results suggest that F0.9 has the potential to be used as a source of sulfated galactan antinociceptive and anti-inflammatory

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The exopolysaccharides are extracellular compounds produced by some species of fungi and bacteria. It is suggested that these molecules, even when in the form of complex polysaccharide-peptide, are the main bioactive molecules of many fungus. Some of the biological activities displayed by these compounds can be accentuated and others may arise when you add chemically polar or nonpolar groups to polysaccharides. The fruiting body of Pleurotus sajor-caju produces a heteropolysaccharide with antineoplastic and antimicrobial activity, but other biological activities of this polymer have not been evaluated. In this work the exopolysaccharide of Pleurotus sajor-caju was sulfated chemically and structurally characterized. We also evaluated the antiproliferative, antioxidant and anticoagulant activities from native exopolysaccharide (PN) and its sulfated derivated (PS). Polyacrylamide gel electrophoresis, infrared spectroscopy and nuclear magnetic resonance (¹³C) proved successful in sulfation of PN to obtain PS. Analysis by gas chromatography-mass spectroscopy showed that PN and PS are composed of mannose, galactose, 3-O-methyl-galactose and glucose in proportion percentage of 44,9:16,3:19,8:19 and 49, 7:14,4:17,7:18,2, respectively. The percentage of sulfate found in PS was 22.5%. Antioxidants assays revealed that the sulfation procedure affects differently the activities of exopolysaccharides, while the total antioxidant capacity, the scavenging activity of superoxide radical and ferric chelating were not affected by sulfation, on the other hand the chemical modification of PN enhanced the scavenging activity of hydroxyl radical and reducing power. PS also showed anticoagulant activity in a dose-dependent manner and clotting time was 3.0 times higher than the baseline value in APTT at 2 mg/mL. The exopolysaccharide not presented antiproliferative activity against HeLa tumor cells, but PS affects the cellular proliferation in a time-dependent manner. After 72 h, the inhibition rate of PS (2.0 mg/mL) on HeLa cells was about 60%. The results showed that PN sulfation increase some of their activities.

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Fucan is a term used to denominate a family of sulfated L-fucose-rich polysaccharides. The brown alga Spatoglossum schröederi (Dictyotaceae) has three heterofucans namely fucan A, B and C. The 21 kDa fucan A is composed of a core of β (1-3) glucuronic acid-containing oligosaccharide of 4.5 kDa with branches at C4 of fucose chains α (1-3) linked. The fucose is mostly substituted at C4 with a sulfate group and at C2 with chains of β (1-4) xylose. This fucan has neither anticoagulant (from from 0.1 to 100µg) nor hemorrhagic activities (from 50 to 800 µg/mL). The antithrombotic test in vivo showed the fucan A has no activity in any of the concentrations (from 0.2 to 20µg/g/day) tested 1h after polysaccharide administration. However, when fucan A was injected endovenously 24h before the ligature of the venae cavae, we observed a dose-dependent effect, reaching saturation at around 20g/g of rat weight. In addition, this effect is also time-dependent, reaching saturation around 16h after fucan administration. In addition, regardless of administration pathway, fucan A displayed antithrombotic action. The exception was the oral pathway. Of particular importance was the finding that fucan A stimulates the synthesis of an antithrombotic heparan sulfate from endothelial cells like heparin. The hypothesis has been raised that in vivo antithrombotic activity of fucan A is related to the increased production this heparan. Taken together with the fact that the compound is practically devoid of anticoagulant and hemorrhagic activity suggests that it may be an ideal antithrombotic agent in vivo

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Aim: The aim of this work was to investigate the hypothesis that catechol and 3MC inhibit FADH2-linked basal respiration in mitochondria isolated from rat liver and brain homogenates. Moreover, catechol ability to induce DNA damage in rat brain cells through the comet assay (alkaline single-cell gel electrophoresis assay) was also observed. Methods: Two different catechols were evaluated: pirocatechol (derived from benzene) and 3-methylcatechol (derived from toluene); rat liver and brain homogenates were incubated with 1mM catechol at pH 7.4 for up to 30 minutes. After that, mitochondrial fractions were isolated by differential centrifugation. Basal oxygen uptake was measured using a Clark-type electrode after the addition of 10 mM sodium succinate for a period of 12 minutes. In additional experiments, rat brain cells were treated with 1, 5 and 10mM pirocatechol for up to 20 minutes at 37º C, and submitted to electrophoresis. Results: Catechols (pirocatechol and 3methylcatechol) induced a time-dependent partial inhibition of FADH2-linked basal mitochondrial respiration. Indeed, pirocatechol was able to produce a dosedependent DNA oxidative damage in rat brain cells by 2 and 4 injury levels. These results suggest that reactive oxygen species generated by the oxidation of catechols, induced an impairment on mitochondrial respiration and a DNA damage, which might be related to their citotoxicity. Conclusion: Catechols produced an inhibition of basal respiration associated to FADH2 in isolated liver and brain mitochondria; 3-methylcatechol, at the same concentration, produced similar toxicity in the mitochondrial model. Indeed, pirocatechol induced a DNA damage in rat brain cells, mainly observed in comets formation and consequent DNA degradation