Developments in the analytical methodologies and structure-activity relationships of low molecular weight fucoidans:...

Fucoidan is an acidic polysaccharide associated with a variety of biological functions, including anticoagulant, antithrombotic, immunomodulatory, and antitumor activities. It has been extensively utilized in both the pharmaceutical and food industries. However, the high intra- and intermolecular diversity of fucoidan poses challenges in correlating specific structures with biological functions and in developing practical applications. Low molecular weight fucoidan (LMWF), derived from fucoidan, reduces this complexity, facilitating structural refinement, characterization, and the assignment of structure to function. Additionally, LMWF offers several advantages, such as enhanced solubility, reduced viscosity, and improved absorption, which lead to increased bioavailability and promising potential for application. Nonetheless, a critical gap persists in the literature regarding the ongoing challenges associated with the structural elucidation of LMWF and its impact on bioactivity. Therefore, this review highlights recent advancements in structural characterization methodologies, with a particular emphasis on oligosaccharide mapping and the structure-activity relationship (SAR) of LMWF in relation to its biological functions. Additionally, it presents various techniques for preparing LMWF, including degradation and synthesis techniques. This review aims to serve as a comprehensive and timely reference for the rational design and application of LMWF-based biofunctional systems.