Antitumor potential of alginates isolated from the seaweed brown sargassum vulgare c. agardh (1820)

• Autor(a) principal: Alessandra de Paula Alves Sousa
• Data de Publicação: 2006
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFC
• Texto Completo: http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=8
• topic: Atividade Antitumoral; Sargassum Vulgare; Alga Marinha; Sargassum vulgare; Alginate; Seaweed; Antitumor; FARMACOLOGIA

Alginates are natural polysaccharides composed of linear polymers of 1-4 linked beta-D- mannuronic and alfa-L-guluronic acid residues in widely varying composition and sequential arrangements. The purpose of this study was to evaluate the anti cancer potential of two alginates âV (low viscosity) and +V (high viscosity), isolated from the seaweed Sargassum vulgare. Alginates were tested for cytotoxicity using the brine shrimp lethality assay, sea urchin development assay, hemolysis assay and MTT assay using HL-60, MCF-7, CEM, HCT-8 and B16 tumor cell lines. None of the compounds tested showed in vitro toxicity. On the other hand, alginates showed antitumor activity in vivo against Sarcoma 180 cells transplanted in mice. Both alginates inhibited the growth of solid tumor in mice implanted with 5 x 105 tumor cells after both oral and intraperitoneal administration at 50 and 100 mg/m2, as well as 25 mg/m2 after oral administration. Alginate +V presented higher inhibition effects after oral administration. The association of alginate +V (25 mg/m2) with 5-FU (15 mg/m2) showed an increasing activity against tumor compared to +V individually. Alginates antitumor activity at 50 and 100 mg/m2 was related to the tumor proliferation rate inhibition, as observed by reduction of Ki-67 staining in tumor of the treated-animals. The histopathological analysis revealed that both alginates administrated at 50 and 100 mg/m2 presented hepatotoxicity and nefrotoxicity, being -V was more toxic than +V. The kidney perfusion assay demonstrated that âV was more toxic than +V, corroborating date from histopathological analysis. The histopathological analysis of spleen showed that both alginates cause the enlargement of the white pulp of treated animals, suggesting that the observed antitumor activity could be related to alginates immunomodulatory properties. In fact, the alginates treatment (25 mg/m2) prevents the reduction number of leukocytes and lymphocytes, induced by 5-FU treatment as observed from the hematological analysis.