A Fucan Sulfate with Pentasaccharide Repeating Units from the Sea Cucumber Holothuriafloridana and Its Anticoagulant Activity

Abstract

A fucan sulfate (HfFS) was isolated from the sea cucumber Holothuriafloridana after proteolysis-alkaline treatment and purified with anion-exchange chromatography. The molecular weight (Mw) of HfFS was determined to be 443.4 kDa, and the sulfate content of HfFS was 30.4%. The structural analysis of the peroxidative depolymerized product (dHfFS-1) showed that the primary structure of HfFS was mainly composed of a distinct pentasaccharide repeating unit -[l-Fuc2S4S-α(1,3)-l-Fuc-α(1,3)-Fuc-α(1,3)-l-Fuc2S-α(1,3)-l-Fuc2S-α(1,3)-]n-. Then, the “bottom-up” strategy was employed to confirm the structure of HfFS, and a series of fucooligosaccharides (disaccharides, trisaccharides, and tetrasaccharides) were purified from the mild acid-hydrolyzed HfFS. The structures identified through 1D/2D NMR spectra showed that these fucooligosaccharides could be derivates from the pentasaccharide units, while the irregular sulfate substituent also exists in the units. Anticoagulant activity assays of native HfFS and its depolymerized products (dHf-1~dHf-6) in vitro suggested that HfFS exhibits potent APTT-prolonging activity and the potencies decreased with the reduction in molecular weights, and HfFS fragments (dHf-4~dHf-6) with Mw less than 11.5 kDa showed no significant anticoagulant effect. Overall, our study enriched the knowledge about the structural diversity of FSs in different sea cucumber species and their biological activities.

Bioactive secondary metabolites in sea cucumbers and their potential to use in the functional food industry

“…According to the authors, fucan sulfates isolated from P. mollis had strong and dose-dependent anticoagulant activities under the tested conditions. In another study, fucan sulfate isolated from H. floridana was also found to possess strong APTT-prolonging activity (Ning et al, 2022). Interestingly in this study authors pointed out a positive relationship between molecular weight and APTT-prolonging activity.…”

Purification and Structural Analyses of Sulfated Polysaccharides from Low-Value Sea Cucumber Stichopus naso and Anticoagulant Activities of Its Oligosaccharides

“…The sulfate content of each sample was determined via ion chromatography (IC) using a Dionex ICS2100 ion chromatography system (Thermo Fisher Scientific, USA) [ 10 , 41 ]. A series of sulfate standard solutions (10, 30, 50, 70, and 90 mg/L) was recorded to establish the standard curve.…”