Obtenção de glicosaminoglicanos de escamas de tilápia (Oreochromis niloticus)

Abstract

Glycosaminoglycans (GAGs) are anionic polysaccharide composed of repetitive disaccharide units of hexosamine, uronic acid or galactose. Its selected and biological properties are associated with the density of negative charges in the molecule. There are reports of these structures present in the most varied species, including fish. The production of fish has reached increasingly expressive numbers and Brazil stands out on the international scene. A species with the highest production volume in the country is tilapia, and Paraná is the state with the highest national production volume. Linked to this increase in production and consumption, it is the generation of by-products. The scales represent the part of this material when considering the volume of inclination that was processed. The alternatives for the effective use of the scales represent today, one of the biggest challenges for the processing plants. The work aimed to use tilapia scales as raw carried out by enzymatic hydrolysis with papain, at a temperature of 60 °C, for 14 days. After extraction, the ion exchange column was purified. The fractions obtained with the purification were grouped according to the profiles obtained by the electrical conductivity analyzes and by the determinations of uronic acid and sulfated GAGs. Of all fractions obtained chromatographically, six new fractions were grouped, of these those that showed major peaks in the determinations previously mentioned, were characterized by electrophoresis in agarose gel. The results of electrophoresis and nuclear magnetic resonance (NMR) indicated the presence of sulfated GAG´s in the sample. Based on the NMR spectra, the V fraction (F – V) showed a higher degree of purity, thus enabling the identification of characteristic signals for sulphated GAGs. A mixture of chondroitin sulfate 4 (SC4) and chondroitin sulfate 6 (SC6) was found. This fraction was tested for the degree of substitution (GS) by sulphate groups and presented as GS of 0,146. F –V showed anticoagulant activity, being the most effective actions in higher concentrations. When tested in the presence of protamine, F- V a had a pro-anticoagulant effect. The fraction showed a cytotoxic/antitumor effect against metabolizing cells, derived from Rattus norvegicus hepatoma, thus demonstrating its potential for application for this purpose. The extraction of chondroitin sulfate from tilapia scales can be an alternative for the destination of this by-product, generation economic, social and environmental benefits.