Chemical structure, anti-inflammatory and antinociceptive activities of a sulfated polysaccharide from Gracilaria intermedia algae.

The present work aimed at carrying out the isolation and biochemical characterization of a sulfated polysaccharide fraction (PLS) from the marine algae Gracilaria intermedia and investigating its anti-inflammatory and antinociceptive potential. PLS was obtained through enzymatic digestion with papain and analyzed by means of gel permeation chromatography and Nuclear Magnetic Resonance to 1H and 13C. In order to evaluate the potential of anti-inflammatory action of PLS, we performed paw edema induced by carrageenan, dextran, compound 48/80, histamine and serotonin. In addition, we also measured the concentration of myeloperoxidase, cytokines, the count of inflammatory cells and performed tests of the nociception. The PLS isolated was of high purity and free of contaminants such as proteins, and had molecular weight of 410 kDa. The same macromolecule was able to decrease the paw edema induced by all inflammatory agents (P < 0.05), myeloperoxidase (MPO) activity, neutrophil migration and IL-1ß levels. It also decreased acetic acid-induced writhing (P < 0.05) and formalin-induced paw licking time (P < 0.05), but no in hot plate test. In summary, the PLS decreased the inflammatory response by reducing neutrophil migration and modulating IL-1ß production and antinociceptive effects by a peripheral mechanism dependent on the down-modulation of the inflammatory mediators.

Anti-diarrhoeal therapeutic potential and safety assessment of sulphated polysaccharide fraction from Gracilaria intermedia seaweed in mice.

Sulphated polysaccharides extracted from algae have been extensively studied for their diverse biological activities. Thus, the purpose of this study was to evaluate the chemical composition, the anti-diarrhoeal effect and acute toxicity of a sulphated polysaccharide fraction obtained from Gracilaria intermedia (SP-Gi). Initially, the FT-IR of SP-Gi revealed to be an agaran with sulphation at C-6 of the l-galactosyl residues. The anti-diarrhoeal activity of SP-Gi was evaluated in a castor oil-induced diarrhoea model. The effects of SP-Gi on enteropooling, Na +-K +-ATPase activity, gastrointestinal transit, and gastric emptying were then examined. Subsequently, the effect of SP-Gi on diarrhoea induced by cholera toxin (CT) and Escherichia coli was examined. In addition, an acute toxicity test was conducted in accordance with OECD guideline 423. Pre-treatment with SP-Gi reduces the total faeces, total diarrhoeal faeces, and enteropooling. SP-Gi (30mg/kg p.o.) increased Na+/K+-ATPase activity and reduced gastrointestinal transit through anticholinergic mechanisms. ELISA demonstrated that SP-Gi can interact with GM1 receptors and CT. SP-Gi reduced diarrhoea induced by E. coli and prevented weight loss in the animals. Moreover, SP-Gi did not induce any toxicity signs. These results suggest that SP-Gi is a possible candidate for the treatment of diarrhoeal illnesses.

Sulfated polysaccharide fraction from marine algae Solieria filiformis: Structural characterization, gastroprotective and antioxidant effects.

A sulfated polysaccharide (SFP) fraction from the marine alga Solieria filiformis was extracted and submitted to microanalysis, molar mass estimation and spectroscopic analysis. We evaluated its gastroprotective potential in vivo in an ethanol-induced gastric damage model and its in vitro antioxidant properties (DPPH, chelating ferrous ability and total antioxidant capacity). Its chemical composition revealed to be essentially an iota-carrageenan with a molar mass of 210.9kDa and high degree of substitution for sulfate groups (1.08). In vivo, SFP significantly (P<0.05) reduced, in a dose dependent manner, the ethanol-induced gastric damage. SFP prevents glutathione consume and increase of malondialdehyde and hemoglobin levels. SFP presented an IC50 of 1.77mg/mL in scavenging DPPH. The chelating ferrous ability was 38.98%, and the total antioxidant capacity was 2.01mg/mL. Thus, SFP prevents the development of ethanol-induced gastric damage by reducing oxidative stress in vivo and possesses relevant antioxidant activity in vitro.

The efficacy of a sulphated polysaccharide fraction from Hypnea musciformis against diarrhea in rodents.

Seaweeds are sources of diverse bioactive compounds, such as sulphated polysaccharides. This study was designed to evaluate the chemical composition and anti-diarrheal activity of a fraction of sulphated polysaccharide (PLS) obtained from the red seaweed Hypnea musciformis in different animal models, and to elucidate the underlying mechanisms. PLS was obtained by aqueous extraction, with a yield of 31.8% of the seaweed dry weight. The total carbohydrate content accounted for 99% of the sample. The sulfate content of the polysaccharide was 5.08% and the percentage of carbon was 25.98%. Pretreatment with all doses of PLS inhibited castor oil-induced diarrhea, with reduction of the total amount of stool, diarrheal stools, and the severity of diarrhea. PLS (90 mg/Kg) decreased castor oil- and PGE2-induced enteropooling. In addition, PLS (90 mg/Kg) increased the Na(+)/K(+)-ATPase activity in the small intestine and reduced gastrointestinal transit, possibly via activation of cholinergic receptors. Interestingly, the cholera toxin-induced fluid secretion and Cl(-) ion levels decreased in the intestinal contents of the animals pretreated with PLS (90 mg/kg), probably via reduction of toxin-GM1 receptor binding. In conclusion, PLS exerts anti-diarrheal activity by increasing Na(+)/K(+)-ATPase activity, inhibiting gastrointestinal motility, and blocking the toxin-GM1 receptor binding.

Sulphated Polysaccharide Isolated from the Seaweed Gracilaria caudata Exerts an Antidiarrhoeal Effect in Rodents.

Diarrhoea is a significant health problem for children in developing countries that causes more than 1 million deaths annually. This study aimed to evaluate the antidiarrhoeal effect of sulphated polysaccharide (PLS) from the alga Gracilaria caudata in rodents. For the evaluation, acute diarrhoea was induced in Wistar rats (150-200 g) by administration of castor oil (10 mg/kg). Then, different parameters, including enteropooling and gastrointestinal transit and its pharmacological modulation by opioid and cholinergic pathways, were assessed using activated charcoal in Swiss Mice (25-30 g). Secretory diarrhoea was examined using cholera toxin (CT) (1 mg/loop)-treated, isolated intestinal loops from Swiss mice (25-30 g), which were also used to examine fluid secretion, loss of chloride ions into the intestinal lumen and absorption. In addition, a GM1-dependent ELISA was used to evaluate the interaction between PLS, CT and the GM1 receptor. Pre-treatment with PLS (10, 30 and 90 mg/kg) reduced faecal mass, diarrhoeal faeces and enteropooling. However, 90 mg/kg more effectively reduced these symptoms; therefore, it was used as the standard dose in subsequent experiments. Gastrointestinal transit was also reduced by PLS treatment via a cholinergic mechanism. Regarding the diarrhoea caused by CT, PLS reduced all study parameters, and the ELISA showed that PLS can interact with both the GM1 receptor and CT. These results show that PLS from G. caudata effectively improved the parameters observed in acute and secretory diarrhoea, which affects millions of people, and may lead to the development of a new alternative therapy for this disease.

Polysaccharide isolated from Passiflora edulis: Characterization and antitumor properties.

A hot water-extracted polysaccharide fraction (PFCM) of Passiflora edulis was characterized by microanalysis, infrared spectroscopy, NMR and high performance size-exclusion chromatography. The major component in PFCM is (1→4) linked galacturonic acid (esterified and unesterified). Neutral sugars such as arabinose, glucose, rhamnose, mannose, and fucose were also present. Traces of xylose and ribose were detected. The PFCM sample had a similar molar mass to that of pectin extracted from P. edulis under acidic conditions. Sarcoma 180 tumors treated with PFCM showed a growth inhibition ratio ranging from 40.59% to 48.73% depending on the dosage and type of PFCM administration (oral or intraperitoneal). Toxicological analysis shows that PFCM increases the cell types involved in primary defense mechanisms and no significant changes in the biochemical parameters and organs (e.g., kidney and liver) were observed. However, the use of PFCM treatment increased the spleen weight when compared with the use of 5-fluorouracil.