Low molecular weight fucoidan: Production methods and their therapeutic applications

Low molecular weight fucoidan (LMWF), a depolymerized form, is known to possess superior bioactivities compared to its high molecular weight counterparts. This review critically examines the current strategies for the depolymerization of fucoidan and discusses the therapeutic applications of LMWF. Common methods for fucoidan depolymerization include enzymatic degradation, photocatalytic degradation, radical degradation, acid hydrolysis, ultrasound-assisted degradation, hydrogen peroxide-mediated hydrolysis, and hydrothermal degradation. Among these methods, enzymatic degradation stands out, allowing controlled molecular weight reduction while preserving its structural integrity. The LMWF was found to have wide therapeutic applications owing to its bioactivities such as anti-inflammatory, antioxidant, antidiabetic, anticancer, hypolipidemic, antiobesity, liver protective and nephroprotective activities. The molecular weight significantly influences the bioactivities of LMWF, along with the degree of sulfation, monosaccharide composition, ratio and uronic acid content. LMWF has excellent potential for use in nutraceutical and pharmaceutical applications owing to its therapeutic value. Given that the depolymerization method influences the characteristics and bioactivities of LMWF, careful selection and optimization of these depolymerization techniques can help to produce LMWF with enhanced therapeutic efficacy. This review offers insights to guide future research, both in developing advanced depolymerization strategies and in conducting in-depth studies on the therapeutic applications of LMWF.