Biochemical and transcriptomic characterization of low-molecular-weight fucoidan with potential applications in oral biomaterials.

Fucoidan is a sulfated polysaccharide from brown algae with potential as a marine-derived biomaterial for oral healthcare. This study compared crude fucoidan, purified fucoidan, and low-molecular-weight fucoidan (LMF) to clarify the relationship between physicochemical properties and biological activity. Iodine content was quantified by mass spectrometry, collagenase inhibition against MMP-8 and MMP-13 and antioxidant capacity were evaluated using biochemical assays, and cellular responses were assessed in oral squamous carcinoma (SAS) cells and normal fibroblasts. Among the preparations, LMF showed the highest iodine content and the strongest inhibition of collagenases and reactive oxygen species. Fucoidan selectively reduced the viability of SAS cells while sparing fibroblasts. RNA sequencing revealed activation of apoptosis-related pathways and suppression of survival signaling in SAS cells, whereas fibroblasts exhibited stress-adaptive transcriptional profiles. These results indicate that LMF exerts selective cytotoxic and tissue-protective effects, supporting its application as a functional dental biomaterial.