Inhibitory Effect of Ethanol Extract of <i>Angelica gigas</i> Nakai on Biofilm Formation and Metabolic Activity of <i>Streptococcus mutans</i> according to Xylitol and Sucrose

Background: Angelica gigas Nakai Root (AGN) is a medicinal plant with various therapeutic effects.The purpose of this study was to determine the effect of a 70% ethanol extract of AGN (EAGN) on biofilm formation and metabolic activities of Streptococcus mutans according to exposure to xylitol and sucrose, and to confirm the possibility of using EAGN as an effective medicinal plant-derived anti-cariogenic substance.Methods: Bacterial growth and disk diffusion test were performed to confirm the antibacterial effects of EAGN against S. mutans in a brain-heart infusion (BHI) medium containing 1% xylitol and 1% sucrose, measurement of.Biofilm formation was confirmed using a biofilm formation assay and glycosyltransferase (GTF) activity.Metabolic activity was evaluated using a calcium assay, acid production assay and buffering capacity measurements.Results: EAGN showed antibacterial activity against S. mutans in a BHI medium containing 1% xylitol and sucrose.At 3.75 and 5.0 mg/ml EAGN in S. mutans-inoculated medium containing 1% sucrose, the antibacterial effect was greater than those of BHI only and 1% xylitol BHI media.In S. mutans-inoculated medium containing 1% sucrose, cariogenic biofilm formation, GTF activity, released Ca 2+ levels, and acidogenicity were significantly increased, but the buffering capacity was significantly decreased.According to EAGN treatment, cariogenic biofilm formation, GTF activity, measured released Ca 2+ levels, and acidogenicity were significantly decreased and buffering capacity was significantly increased.An EAGN over 3.75 mg/ml significantly reduced biofilm formation and Ca 2+. Regardless of the concentration of EAGN, acidogenicity was reduced, and the buffering capacity was increased.Conclusion: EAGN is a safe natural anti-cariogenic substance that inhibits biofilm formation by directly inhibiting GTF activity and adjusts the microenvironment for tooth remineralization by reducing Ca 2+ and acidogenicity and increasing the buffering capacity according to exposure to sucrose in S. mutans.