Low Molecular Weight, 4-O-Sulfation, and Sulfation at Meta-Fucose Positively Promote the Activities of Sea Cucumber Fucoidans on Improving Insulin Resistance in HFD-Fed Mice

Abstract

Fucoidans from sea cucumber (SC-FUC) have been proven to alleviate insulin resistance in several species. However, there are few studies that clarify the relationship between their structure and bioactivity. The present study evaluated the influence of molecular weight (Mw), sulfation concentrations (Cs), and sulfation position on improving insulin resistance using SC-FUC. Results showed that fucoidans with lower Mw exerted stronger effects. Having a similar Mw, Acaudina molpadioides fucoidans (Am-FUC) with lower Cs and Holothuria tubulosa fucoidans with higher Cs showed similar activities. However, Isostichopus badionotus fucoidans (higher Cs) activity was superior to that of low-Mw Thelenota ananas fucoidans (Ta-LFUC, lower Cs). Eliminating the effects of Mw and Cs, the bioactivity of Am-FUC with sulfation at meta-fucose exceeded that of Ta-FUC with sulfation at ortho-position. Moreover, the effects of Pearsonothuria graeffei fucoidans with 4-O-sulfation were superior to those of Am-LFUC with 2-O-sulfation. These data indicate that low Mw, 4-O-sulfation, and sulfation at meta-fucose contributed considerably to insulin resistance alleviation by SC-FUC, which could accelerate the development of SC-FUC as a potential food supplement to alleviate insulin resistance.

Prospects of sea buckthorn ( Hippophae rhamnoides L.) polysaccharides: preparation, structural characterization, and bioactivities diversity

“…However, if the Mw is too low, the polysaccharide will not be able to form an active structure, thus reducing its biological activity [101] . Zhu et al [33] isolated two fractions, HRP-1 and HRP-2, from sea buckthorn polysaccharides, but the smaller Mw HRP-2 exhibited more significant antioxidant and immune-enhancing effects than the larger Mw HRP-1.…”

Potential Application of Marine Fucosyl-Polysaccharides in Regulating Blood Glucose and Hyperglycemic Complications

“…The same results were found in a study on SC-FUC. Hu et al found that degraded Am-FUC was more effective at relieving insulin resistance [ 85 ]. In recent years, marine oligosaccharides or low-molecular-weight polysaccharides have been shown to have hypoglycemic effects, the advantages of which are expressed in the stimulation of insulin secretion [ 107 ].…”

“…Hu et al studied the effects of sulfation position on improving insulin resistance from five SC-FUC from different sources. It is inferred that meso-fucose is better at alleviating IR, and 4- O -sulphate substitution in SC-FUC is more beneficial than 2- O -sulphate substitution is at alleviating IR [ 85 ]. Studies have also shown that the 4- O -sulfated structure is vital in treating metabolic syndrome functional groups [ 77 , 120 ].…”