Search

Polysaccharides from seaweed have been shown to present a variety of antitumor effects, however the understanding of which structural patterns are responsible for these biological effects are still unclear. This review aimed to gather and critically evaluate published data of seaweed polysaccharide's chemical structure elucidation and their relation with antimelanoma effects. Data were collected at the electronic article databases Science Direct, NCBI/Pubmed and Google Scholar, selecting papers with polysaccharide structural information and biological effects on melanoma models. Most of the papers referred to sulfated polysaccharides as fucans and fucoidans, and to a lesser extent galactans, rhamnans, alginates, and neutral one's glucans. Fine chemical features as presence and position of sulfate groups, monosaccharide composition, linear or branched backbones, and glycosidic linkage type are crucial to antimelanoma effects, as well as molecular weight and macromolecular conformation.

Polysaccharides α-D-galactan (GAL-Am) and β-D-glucan (GLC-Am) were obtained from Amanita muscaria fruiting bodies. They were purified using different methodologies, such as Fehling precipitation (for both fractions), freeze-thawing process and ultrafiltration (for GLC-Am). Results showed that the GAL-Am has (1 → 6)-linked Galp main chain branched at O-2 by terminal Galp units and has not been previously reported. Besides, GLC-Am has (1 → 3)-linked Glcp in the main chain, substituted at O-6 by (1 → 6)-linked β-Glcp units. Both are water-soluble, with 9.0 × 103 g/moL and 1.3 × 105 g/moL, respectively. GAL-Am and GLC-Am presented a selective proliferation reduction against B16-F10 melanoma cell line, not affecting non tumoral BALB/3T3 fibroblast cell line. Furthermore, both fractions reduced clonogenic capacity of melanoma cell line over an extended period of time. These results were obtained without modulations in B16-F10 cell adhesion, reinforcing the biological activities towards cell proliferation impairment and eliciting these polysaccharides as promising compounds to further exploration of their antimelanoma properties.

Melanoma is the most lethal form of skin cancer, with a worldwide increase in incidence. Despite the increased overall survival of metastatic melanoma patients given recent advances in targeted and immunotherapy, it still has a poor prognosis and available treatment options carry diverse severe side effects. Polysaccharides from seaweed have been shown to exert antitumor activities. Here we show in vitro and in vivo antitumor activities of a sulfated homogalactan (named 3G4S) from Codium isthmocladum seaweed in the B16-F10 murine melanoma cell line. 3G4S did not induce cytotoxicity or proliferation changes; however, it was able to reduce solid tumor growth and metastasis, while not inducing side effects in mice. B16-F10 cells traits related to the metastatic cascade were also impaired by 3G4S, reducing cell invasion, colony-forming capacity and membrane glycoconjugates. Therefore, 3G4S shows promising antitumor activities without the commonly associated drawbacks of cancer treatments and can be further explored.