Funoran as a marine anti-biofilm polysaccharide for caries prevention: biological basis, current evidence, and translational challenges.

Dental caries is a chronic biofilm-mediated disease that is caused by the interplay of plaque dysbiosis, persistent acid generation by cariogenic bacteria and host-associated environmental influences. Accordingly, current anti-caries measures increasingly focus on broader interventions targeting bacterial adhesion and colonization, biofilm formation, extracellular polysaccharide (EPS) production, and the local oral microecological equilibrium. Funoran, a sulfated polysaccharide derived from red algae, has become a promising natural marine bioactive, because it has desirable biocompatibility, interfacial activity, and potential anti-adhesive and antibiofilm properties. Current evidence suggests that funoran can reduce the adhesion of oral streptococci to tooth-relevant surfaces and may improve biofilm inhibition when combined with agents such as xylitol. Studies on structurally related algal polysaccharides further support the potential of marine polysaccharides in antibacterial, antibiofilm, anti-inflammatory, and oral delivery applications. Nevertheless, the development of funoran for caries prevention is still constrained by limited direct evidence, unclear mechanisms, non-standardized evaluation systems, and insufficient clinical research. Future studies should emphasize structural characterization, mechanistic investigation, standardized biological evaluation, and local delivery design to accelerate its translation into precision caries prevention.