Caracterização química, atividade antioxidante e gastroprotetora de polissacarídeos sulfatados da alga marinha vermelha Gracilaria cearensis

Abstract

The red seaweed of the genus Gracilaria have in their chemical composition sulphated polysaccharides and are widely used in the food area as stabilizing and emulsifiers. In the industrial area as a base for shampoos and cosmetics. Recently in the pharmaceutical area the polysaccharides of marine algae have been studied due to their biological activities, presenting antioxidant, gastroprotective, antiviral activities, among others. The objective of this work was to collect, extract, characterize and evaluate the antioxidant and gastroprotective potential of a sulphated polysaccharides obtained from the red algae Gracilaria cearensis (PSGC). The sulphated polysaccharides was obtained from enzymatic extraction with papain from dried and macerated samples of the red algae Gracilaria cearensis. The amount of total carbohydrates and protein residues were evaluated by colorimetric tests. It was observed yield in the extraction of 17.32%, characterizing a good yield in comparison with other algae of the genus Gracilaria. The amount of protein in the sample was irrelevant, demonstrating the efficiency in the extraction. The chemical characterization was performed using infrared spectroscopy (IR) and nuclear magnetic resonance of carbon and hydrogen (MNR-C13, MNR-H1) and single heteronuclear quantum coherence (HSQC) tests. The average molar mass was determined by gel permeation chromatography (GPC). The PSGC was shown to be a furanan type agarane having a molecular weight of 246.34 KDa. Gastroprotection tests were performed by oral ingestion of ethyl alcohol in swiss female observing the action of PSGC. Gastric protection rates were observed around 60 to 80% against ethanol, resulting in a maximum protection of 82.4% in concentrations of 10 mg/mL of the PSGC. Antioxidant tests were performed (antioxidant activity by ferrous ion chelation, formation of the phosphomolybdenum complex and sequestration of the diphenyl-picrylhydrazyl-DPPH radical) in order to understand the mechanism of gastric protection. About 78% of the antioxidant activity of ferrous ion chelation was observed, possibly indicating that the gastroprotective action of Gracilaria cearensis polysaccharide (PSGC) is related to the chelation of hydroxyl groups of the reactive oxygen species (ROS) molecules. Thus, PSGC can be considered an antioxidant biomolecule and presents an gastroprotective action, and may be used as a possible auxiliary drug in gastroprotective treatments in the future.