Preliminary chemical study of the polysaccharides of the alga gracilariopsis hommersandii (rhodophyta)

Abstract

Marine organisms are an important source of substance of great interest, with marine algae producing large amounts of polysaccharides of different types. Algae are considered a useful renewable resource, given that, among other components, sulphated polysaccharides possess biological activity such as antiviral, antitumor, anticoagulant activity, among many others, in addition to having multiple industrial applications. This research aims to present the results of the preliminary chemical analysis of the water soluble polysaccharides present in the cell wall of the seaweed Gracilariopsis hommersandii (Gracilariales) Rhodophyta. It is known that most red algae produce galactans with different degrees of sulphation. Those of the order Gracilariales biosintetizan agaranos, family of polysaccharides to which it belongs, among others, agar-agar (constituted mainly by agarose). The dry algal material was extracted with methanol and the residue from the methanolic extraction was extracted twice, with water at room temperature, and once, with hot water. It was determined that the hot extract was the most important, being the most interesting from the point of view of possible industrial applications of these algae; however, the interest of the extracts obtained at room temperature could come from an important biological activity, which may be different from that of the main product.The quantitative determination of total carbohydrates was carried out by means of the colorimetric method of phenol-sulfuric acid without prior hydrolysis of the polysaccharide and using galactose as standard for each of the extracts. Also, the determination of sulphate was carried out, which was done using the turbidimetric method. The results showed that the extracts are composed of carbohydrates between 52-71%, the sulfate content was 1116%, and that of proteins 2-5%. The study is expected to continue with the chemical and spectroscopic characterization of these polysaccharides.