The preparation and anti-atherosclerotic effects of different low-molecular weights fucoidan

Fucoidan, a marine-derived sulfated polysaccharide, exhibits a broad spectrum of biological activities. However, its high molecular weight and viscosity often restrict these benefits. In this study, a new fucoidanase-producing microbial strain Kosakonia oryzendophytica LH-58 was isolated from freshwater for the first time. Three low-molecular-weight fucoidans were synthesized through enzymatic hydrolysis, and their antioxidant, hypoglycemic, hypolipidemic, and anticoagulant properties were evaluated in vitro. With the hydrolysis of fucoidan by fucoidanase, there was no significant change in the composition of monosaccharides, and the sulfate content decreased slightly. Interestingly, reduced molecular weight enhanced antioxidant activity, though anticoagulant efficacy diminished. In vitro experiments demonstrated that a higher molecular weight of fucoidan significantly prolonged activated partial thromboplastin and thrombin times. The fraction F1, with a weight-average molecular weight exceeding 10 kDa, displayed superior hypoglycemic and lipid-lowering effects compared to its counterparts. The IC50 values for F1's inhibition of α-amylase and α-glucosidase were 0.81 mg/mL and 0.94 mg/mL, respectively, while its binding rates to sodium taurocholate and sodium glycocholate were 50.11% ± 2.32% and 54.58% ± 2.71%, respectively. This study also offers a methodological reference for the swift identification of functional polysaccharides to prevent atherosclerosis.