Chistiane Oliveira Coura

Antinociceptive and Anti-Inflammatory Activities of Sulphated Polysaccharides from the Red Seaweed Gracilaria cornea

Seaweeds have attracted special interest as good sources of sulphated polysaccharides (SP) for use in pharmaceutical industries and biotechnology. In this study, we evaluated the effects of SP from the red seaweed Gracilaria cornea (Gc-TSP) in nociceptive and inflammatory models. In mice, Gc-TSP (3, 9 or 27 mg/kg) significantly reduced nociceptive responses, as measured by the number of writhes, at all tested doses. In a formalin test, Gc-TSP significantly reduced licking time in both phases of the test at a dose of 27 mg/kg. In a hot-plate test, the antinociceptive effect was observed only in animals treated with 27 mg/kg of Gc-TSP, suggesting that the analgesic effect occurs through a central action mechanism at the highest dose. Gc-TSP (3, 9 or 27 mg/kg) caused only a slight reduction in neutrophil migration in the rat peritoneal cavity. However, lower doses of Gc-TSP (3 and 9 mg/kg) significantly inhibited paw oedema induced by carrageenan, especially at 3 hr after treatment. Reduction in oedema was confirmed by myeloperoxidase activity in the affected paw tissue. In addition, treatment (s.c.) of animals with different doses of Gc-TSP inhibited paw oedema induced by dextran within the first hour in all doses tested. After 14 consecutive days of intraperitoneal administration of Gc-TSP (9 mg/kg), we measured the wet weight of the liver, kidney, heart, spleen and thymus and performed biochemical, haematological and histopathological evaluations. No systemic damage was found. These results indicate that Gc-TSP possesses analgesic and anti-inflammatory effects and is a potentially important tool worthy of further study.

Mechanisms involved in the anti-inflammatory action of a polysulfated fraction from Gracilaria cornea in rats.

The anti-inflammatory mechanisms of the sulfated polysaccharidic fraction obtained from red marine alga Gracilaria cornea (Gc-FI) were investigated using a paw edema model induced in rats by different inflammatory agents (carrageenan, dextran, serotonin, bradykinin, compound 48/80 or L-arginine). Gc-FI at the doses of 3, 9 or 27 mg/kg, subcutaneously - s.c., significantly inhibited rat paw edema induced by carrageenan and dextran, as confirmed by myeloperoxidase and Evans’ blue assessments, respectively. Gc-FI (9 mg/kg, s.c.) inhibited rat paw edema induced by histamine, compound 48/80 and L-arginine. Additionally, Gc-FI (9 mg/kg, s.c.) inhibited Cg-induced edema in animals with intact mast cells but did not inhibit that with degranulated mast cells by compound 48/80, revealing a protective role on mast cell membranes. Gc-FI down-regulated the IL-1β, TNF-α and COX-2 mRNA and protein levels compared with those of the carrageenan group, based on qRT-PCR and immunohistochemistry analyses. After inhibition with ZnPP IX, a specific heme oxygenase-1 (HO-1) inhibitor, the anti-inflammatory effect of Gc-FI was not observed in Cg-induced paw edema, suggesting that the anti-inflammatory effect of Gc-FI is, in part, dependent on the integrity of the HO-1 pathway. Gc-FI can target a combination of multiple points involved in inflammatory phenomena.

Peripheral antinociception and anti-inflammatory effects of sulphated polysaccharides from the alga Caulerpa mexicana.

Sulphated polysaccharides from marine algae are widely used in biotechnological and pharmaceutical areas. In this study, we evaluated the effects of sulphated polysaccharides from the green marine alga Caulerpa mexicana (Cm‐SPs) in nociceptive and inflammatory models in rodents. Cm‐SPs (10 or 20 mg/kg), administered i.v. in Swiss mice, significantly reduced nociceptive responses, as measured by the number of writhes in response to acetic acid. Cm‐SPs (10 or 20 mg/kg) also reduced second‐phase responses in the formalin test, but did not exhibit a significant antinociceptive effect in the hot plate test, suggesting that its antinociceptive action occurs through a peripheral mechanism. Cm‐SPs (5, 10 or 20 mg/kg), administered s.c. in wistar rats 1 hr before carrageenan, dextran, histamine or serotonin, were tested in paw oedema models. Cm‐SPs (10 or 20 mg/kg) reduced carrageenan‐induced paw oedema and myeloperoxidase activity in the paw. In addition, Cm‐SPs (20 mg/kg) inhibited dextran‐ or histamine‐induced paw oedema, but not serotonin‐induced oedema, suggesting that histamine is the major target of Cm‐SPs anti‐oedematogenic activity. Finally, Cm‐SPs (20 mg/kg) administered in mice did not show significant signs of toxicity. In conclusion, Cm‐SPs appear to be promising natural modulatory agents for pain and inflammatory conditions.

Isolamento, fracionamento e avaliação toxicológica in vivo de polissacarídeos sulfatados de Hypnea musciformis

ABSTRACT This study aimed to isolate, fractionate andevaluate the in vivo toxicity of sulfated polysaccharides (SPs)from Hypnea musciformis (Rhodophyta), when obtained bythree extraction methods (M I, M II and M III). SPs wereextracted with papain in 100mM sodium acetate (pH 5.0)containing cysteine and EDTA (5mM) (M I) or water (25-80°C(M II), 80°C (M III)), and then their chemical composition oftotal carbohydrates, free sulfate (FS) and contaminant proteins(CPs) was determined. SPs were submitted to ion-exchangechromatography (DEAE-celulose) using a sodium chloridegradient, being the degree of homogeneity and charge densityevaluated by agarose gel electrophoresis of the fractionsobtained and compared to heparin. The in vivo assay wasperformed using groups (n=6) of male and female Swiss mice(24-33g), which received: SPs (9mg kg -1 , i.p.) absence of CPs(M I) and 0.9% saline (0.1mL 10g -1 , i.p.), for 14 consecutivedays. On the 15 th day, collect blood and organs for biochemicaldosages and corporal mass correlation, respectively, from theanimals anesthetized and sacrificed were performed. The sulfatecontent of FS (31.05±0.53%) (P 0.05)

Neuroprotective Effects of Sulphated Agaran from Marine Alga Gracilaria cornea in Rat 6-Hydroxydopamine Parkinson's Disease Model: Behavioural, Neurochemical and Transcriptional Alterations.

Parkinsons disease (PD) is a multifactorial disease associated with the degeneration of dopaminergic neurons and behavioural alterations. Natural bioactive compounds may provide new therapeutic alternatives for neurodegenerative disorders, such as PD. The sulphated polysaccharides isolated from marine algae are heterogenic molecules that show different biological activities. The red marine alga Gracilaria cornea has a sulphated polysaccharide (SA‐Gc) with structure and anti‐inflammatory and antinociceptive activities reported in the literature. Therefore, this study aimed to evaluate the neuroprotective effects of SA‐Gc in rat model PD induced by 6‐hydroxydopamine (6‐OHDA). Firstly, we established the PD model in rats, induced by an intrastriatal injection (int.) of 6‐OHDA, followed by a single administration of SA‐Gc (15, 30 or 60 μg; int.). On the 14th day, behavioural tests were performed. After killing, brain areas were dissected and used for neurochemical and/or transcriptional analyses. The results showed that SA‐Gc (60 μg, int.) promoted neuroprotective effects in vivo through reducing the oxidative/nitroactive stress and through alterations in the monoamine contents induced by 6‐OHDA. Furthermore, SA‐Gc modulated the transcription of neuroprotective and inflammatory genes, as well as returning behavioural activities and weight gain to normal conditions. Thus, this study reports the neuroprotective effects of SA‐Gc against 6‐OHDA in rats.

Mechanisms involved in antinociception induced by a polysulfated fraction from seaweed Gracilaria cornea in the temporomandibular joint of rats

Temporomandibular disorder is a common clinical condition involving pain in the temporomandibular joint (TMJ) region. This study assessed the antinociceptive effects of a polysulfated fraction from the red seaweed Gracilaria cornea (Gc-FI) on the formalin-induced TMJ hypernociception in rats and investigated the involvement of different mechanisms. Male Wistar rats were pretreated with injection (sc) of saline or Gc-FI 1h before intra- TMJ injection of formalin to evaluate the nociception. The results showed that pretreatment with Gc-FI significantly reduced formalin-induced nociceptive behavior. Moreover, the antinociceptive effect of the Gc-FI was blocked by naloxone (a non-selective opioid antagonist), suggesting the involvement of opioids selective receptors. Thus, the pretreatment with selective opioids receptors antagonists, reversed the antinociceptive effect of the Gc-FI in the TMJ. The Gc-FI antinociceptive effect depends on the nitric oxide/cyclic GMP/protein kinase G/ATP-sensitive potassium channel (NO/cGMP/PKG/K+ATP) pathway because it was prevented by pretreatment with inhibitors of nitric oxide synthase, guanylate cyclase enzyme, PKG and a K+ATP blocker. In addition, after inhibition with a specific heme oxygenase-1 (HO-1) inhibitor, the antinociceptive effect of the Gc-FI was not observed. Collectively, these data suggest that the antinociceptive effect induced by Gc-FI is mediated by μ/δ/κ-opioid receptors and by activation NO/cGMP/PKG/K+ATP channel pathway, besides of HO-1.