Anticoagulant Activity of Rhamnan Sulfate Isolated from Commercially Cultured <i>Monostroma nitidum</i>

Abstract

Abstract:The green seaweed, Monostroma nitidum, is widespread in Japan. In Okinawa Prefecture, the production of seaweed is performed using culture-nets that are seeded artificially. Algae contain a soluble polysaccharide, rhamnan sulfate. To estimate its applicability, the anticoagulant activity of rhamnan sulfate was investigated. Rhamanan sulfate was fractionated by ion-exchange chromatography on a DEAE-sepharose column, and two fractions (A and B) were obtained. Partially hydrolyzed rhamnan sulfates with different molecular mass (C1, C2 and C3) were also prepared. The activated partial thromboplastin time (APTT) test, prothrombin time (PT) and thrombin time (TT) were applied using human plasma and compared with standard heparin (174 units/mg). The native rhamnan sulfate (molecular mass, 630 kDa; sulfuric acid content, 22.7%), fraction A (12.4%) and fraction B (27.8%) showed approximately 73% APTT activity in comparison with that of standard heparin, but fraction C2 (molecular mass, 450 kDa) had a higher activity than that of the standard (107%). On the other hand, in the PT assay, all fractions except fraction C2 and C3 (370 kDa) showed higher activity approximately 120-155% greater than that of standard heparin. The TT activity of rhamnan sulfate depended on the sulfate content, and that of fraction B, which has high sulfuric acid content (27.8%), was 135-173% greater than that of heparin. The sulfate groups of L-rhamnosyl residues and carboxyl group of D-glucuronosyl residue on the trisaccharide side chains of the rhamnan sulfate might interact strongly with the active site of thrombin molecules. The results and discussion suggested that rhamnan sulfate from commercially cultured Monostroma nitidum could be a potential anticoagulant polysaccharide.

Sulfated Glycans Inhibit the Interaction of MERS-CoV Receptor Binding Domain with Heparin

“…RS [ 18 , 32 ], discovered in a green seaweed M. nitidum , is a rhamnose-predominant, high-molecular-weight glycan fraction with high sulfation. The RS backbone is primarily composed of repeating units [→3)-α-L-Rhap-(1→, →2)-α-L-Rhap-(1→, and →2,3)-α-L-Rhap-(1→], with significant sulfation occurring at the C4 hydroxyl groups.…”

Rehashing Our Insight of Seaweeds as a Potential Source of Foods, Nutraceuticals, and Pharmaceuticals

“…Similarly, polycarboxyl ulvans prepared with the same species showed clotting times in the range of 101-227 s, which was 7.7 to 17.9 times higher than native ulvans [267]. In another study, 75 µg/mL of polysaccharide extracted from Monostroma nitidum showed 107%, 120-123%, and 167% higher inhibition activities for APPT, PT, and TT assays, respectively, compared to standard heparin [268]. Polysaccharide from Monostroma angicava was also found to be effective in increasing the clotting time in APPT and TT assays and exhibited good anticoagulant activity in in vitro and in vivo studies [269].…”

Anti-SARS-CoV-2 Activity of Rhamnan Sulfate from Monostroma nitidum

“…Different kinds of algae contain different types of sulfated glycans, such as fucoidan, a fucose-containing sulfated glycan found in brown algae, and agar and carrageenan found in red algae. In green algae, ulvans are the principal cell wall matrix polysaccharides of the genus Ulva [7], and rhamnan sulfates (RS) are found in the genus Monostroma [8].…”

“…Marine sulfated polysaccharides often show anticoagulant activity like that exhibited by heparin. Sulfated glycans from green algae, typically consisting of rhamnose, also show anticoagulant activity [8][9][10][11][12][13][14][15]. RS is also bioactive, exhibiting antioxidative, antihyaluronidase, antitumor, anti-obesity, anti-hypercholesterolemic, anti-hyperglycemic, and anti-diabetes activity [16][17][18].…”