Glycosaminoglycans with unique sulfation patterns have been identified in different species of ascidians (sea squirts), a group of marine invertebrates of the Phylum Chordata, sub-phylum Tunicata (or Urochordata). Oversulfated dermatan sulfate composed of [4-α-L-IdoA-(2-O-SO₃)⁻¹ → 3-β-D-GalNAc(4-OSO₃)⁻¹]_n repeating disaccharide units is found in the extracellular matrix of several organs, where it seems to interact with collagen fibers. This dermatan sulfate co-localizes with a decorin-like protein, as indicated by immunohistochemical analysis. Low sulfated heparin/heparan sulfate-like glycans composed mainly of [4-α-L-IdoA-(2-OSO₃)⁻¹ → 4-α-D-GlcN(SO₃)⁻¹ (6-O-SO₃)⁻¹]_n and [4-α-L-IdoA-(2-O-SO₃)⁻¹ → 4-α-D-GlcN(SO₃)⁻¹]_n have also been described in ascidians. These heparin-like glycans occur in intracellular granules of oocyte assessory cells, named test cells, in circulating basophil-like cells in the hemolymph, and at the basement membrane of different ascidian organs. In this review, we present an overview of the structure, distribution, extracellular and intracellular localization of the sulfated glycosaminoglycans in different species and tissues of ascidians. Considering the phylogenetic position of the subphylum Tunicata in the phylum Chordata, a careful analysis of these data can reveal important information about how these glycans evolved from invertebrate to vertebrate animals.

Macroalgae are valuable natural sources for bioprospection and the development of raw materials applicable to the nutrition, health, and agriculture industries. To build a basis for the sustainable use of marine organisms from the Colombian Caribbean, a preliminary study was conducted focusing on known functional compounds in two genera of macroalgae, including the species Acanthophora spicifera (Rhodophyta), Sargassum ramifolium, and Sargassum fluitans (Ochrophyta). This study included the extraction and identification of polysaccharides using ultrafiltration, nuclear magnetic resonance (¹H-NMR), Fourier-transform infrared spectroscopy (FT-IR), and size exclusion chromatography (SEC); fatty acids by gas chromatographic (GC) profiling; and phenolic composition and antioxidant activity by complementary semi-quantitative methods (ABTS, DPPH, FRAP, and ORAC assays). Carrageenan-type polysaccharides were detected in A. spicifera, while alginate and fucoidan types were found in S. ramifolium and S. fluitans; palmitic acid was the predominant fatty acid in A. spicifera and S. ramifolium, but it was not detected in S. fluitans. S. ramifolium showed the highest ABTS, DPPH, and ORAC activities and phenolic compounds, while S. fluitans exhibited the highest FRAP activity. This study contributes to the chemical knowledge on Colombian macroalgae to establish potential applications in various fields, including biomedicine, cosmetics, functional foods, and nutraceutical ingredients.

Objetivos: El efecto anticoagulante y la citotoxicidad de una fracción de polisacáridos de alto peso molecular (1000RS), obtenida de la túnica de la ascidia Microcosmus exasperatus, fueron evaluados. Métodos: La actividad anticoagulante de 1000RS fue evaluada mediante los ensayos de tiempo de tromboplastina parcial activado (TTPa), tiempo de trombina (TT), tiempo de protrombina (TP), anti factor Xa y anticoagulante lúpico (dRVVT). La citotoxicidad sobre las células hematopoyéticas murinas fue evaluada usando el método del MTT. Resultados: Esta fracción rica en galactosa mostró ser un anticoagulante potencial debido a su efecto inhibidor de la vía intrínseca de la coagulación. Así mismo, las dosis anticoagulantes de esta fracción no afectan la viabilidad celular, lo cual ratifica su potencial como agente terapéutico. Conclusión: El efecto anticoagulante in vitro de 1000RS ocurre a dosis inocuas, sin embargo, éste debe ser evaluado en modelos in vivo, así como su citotoxicidad sobre células humanas normales.