Anti-Thrombin, Anti-Adhesive, Anti-Migratory, and Anti-Proliferative Activities of Sulfated Galactans from the Tropical Green Seaweed, Udotea flabellum

Abstract

In this study, sulfated polysaccharide-rich extracts were isolated from 22 tropical seaweeds (4 red, 11 brown, and 7 green) found in northeastern Brazil, and evaluated for the role of anticoagulant agents. Fifteen of the extracts showed anticoagulant activity, including all the extracts from green seaweeds. Udotea flabellum (a green seaweed) extract was the most potent, requiring an amount of only 3 µg to double the plasma coagulation time in the activated partial thromboplastin time test. A similar result was obtained with 1 µg of heparin. Two sulfated homogalactans with anticoagulant activity, F-I (130 kDa) and F-II (75 kDa), were isolated from this extract using several bio-guided purification steps. Their anticoagulant activity, as well as properties related to antitumor activity (anti-proliferative, anti-adhesive, and anti-migratory), were accessed. Their anticoagulant activities were close to that of heparin. We found that F-I and F-II (0.5–10 μg/mL) were not able to directly inhibit thrombin. In the presence of anti-thrombin, F-I (0.5 μg/mL) was more effective than heparin (0.5 μg/mL) in inhibiting thrombin, while F-II showed similar effects as heparin. F-I and F-II also inhibited B16-F10 (murine melanoma cells) adhesion, migration, and proliferation on a fibronectin-coated surface, but not on laminin- or collagen I-coated surfaces. Except for the antiproliferative activity, the other effects of F-I and F-II were eliminated upon their desulfation (~50%), indicating that the degree of sulfation is not as important for F-I and F-II anti-proliferative activity as the sulfation position. Taken together, the results provide strong evidence for the potential utility of sulfated galactans from U. flabellum, making these compounds an interesting option for future investigations that aim to design new anticoagulant/antitumor agents.

The Potential of Sulfated Polysaccharides Isolated from the Brown Seaweed Ecklonia maxima in Cosmetics: Antioxidant, Anti-melanogenesis, and Photoprotective Activities

“…In particular, seaweeds possess a high amount of polysaccharides [13]. Sulfated polysaccharides isolated from seaweeds have been reported to produce numerous health benefits such as activating the immune system, antioxidant, anti-coagulant, UV protective, liver protective, anti-inflammatory, antimicrobial, and anti-cancer activities [14][15][16][17][18][19][20][21]. isolated sulfate polysaccharides (HFPS) from the brown seaweed Hizikia fusiforme and evaluated the UV protective effects of HFPS [15].…”

“…The results indicated that HFPS effective protects against UVB-induced photodamage in both in vitro and in vivo models [15]. Marques et al (2019) isolated sulfated polysaccharides (UFPS) from the greed seaweeds Udotea flabellum and evaluated anticoagulant and antitumor activities of UFPS [19]. The results indicated that UFPS possesses strong anticoagulant and antitumor effects [19].…”

In Vitro Studies Reveal Antiurolithic Effect of Antioxidant Sulfated Polysaccharides from the Green Seaweed Caulerpa cupressoides var flabellata

“…The electrophoretic mobility of C. cupressoides SPs was evaluated by gel electrophoresis in PDA buffer, according to the reported method [46]. Initially, glass slides were coated with 0.6% ( m / v ) agarose in PDA buffer (0.05 M, pH 9.0).…”

Marine Antithrombotics

“…Two SGs from Udotea flabellum were found to exert anticoagulant activity similar to heparin. These compounds were, however, incapable of inhibiting thrombin directly but could inhibit it via AT [ 82 ]. The SGs purified from red seaweed Spyridia hypnoides also showed promising anticoagulant activity, with an aPTT of 25.36 IU and a PT of 2.46 IU at a concentration of 25 µg/mL.…”