Dental plaque biofilms cause various dental diseases; therefore, inhibiting the growths of the dental plaque bacteria which produce biofilms can be a strategy for preventing dental disease. Certain sulfated polysaccharides from marine algae exert antimicrobial activities against human bacterial pathogens in addition to their physiological benefits. On the basis of these observations, the antimicrobial and antibiofilm activities of sulfated polysaccharides from different marine algae were evaluated against dental plaque bacteria. Among the sulfated polysaccharides, a fucoidan from Fucus vesiculosus showed notable antimicrobial activities against the selected dental plaque bacteria, including some foodborne pathogenic bacteria. The minimum inhibitory concentrations were of 125 to 1000 µg mL-1. Regarding the antibiofilm activity, the fucoidan at the concentrations of above 250 µg mL-1 completely suppressed the biofilm formations and planktonic cell growths of Streptococcus mutans and S. sobrinus. However, no eliminative effect on the completed biofilm was observed. The fucoidan consisted of almost fucose base polysaccharide containing approximately 14.0% sulfate content. The average molecular weight of the fucoidan was changed by heat treatment (121 °C for 15 min) and it affected the antimicrobial activity.
Keywords: antimicrobial activity; dental caries; dental plaque biofilm; marine alga; molecular weight; monosaccharide; sulfated polysaccharide.