Streptococcus mutans와 Porphyromonas gingivalis에 대한 상백피(Morus alba root bark) 에탄올 추출물의 항균 효과

Abstract

This study aimed to analyze the antibacterial activity of the ethanol extract of Morus alba root bark (MAEE) against two critical oral pathogens, Streptococcus mutans and Porphyromonas gingivalis. The Griess reaction and WST-1 assays were used to analyze the nitric oxide (NO) inhibitory and cytotoxic effects of MAEE on lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. The antibacterial activity of MAEE was evaluated using a disk diffusion assay and a growth inhibition assay by determining minimum inhibition concentrations (MICs) and minimum bactericidal concentrations (MBCs). MAEE treatment dose-dependently inhibited NO production and had no cytotoxic effect on LPS-stimulated RAW 264.7 cells. Furthermore, MAEE exhibited potent antibacterial activity and more potently generated a clear zone in the presence of S. mutans than P. gingivalis. The MICs of MAEE for S.mutans and P. gingivalis were 0.4 and 0.4~0.8 mg/mL, and its MBCs were 0.4 and 0.8 mg/mL, respectively. In addition, MAEE significantly inhibited the growths of both pathogens, but no dose-dependency was observed. The OD600 of S. mutans treated with MAEE at 3.2 mg/mL for 24 h was 0.146 compared to a control OD600 of 0.509. Absorbance at 600 nm for P. gingivalis treated with MAEE at 3.2 mg/mL for 24 h was 0.154 compared to a control OD600 of 0.486. In conclusion, MAEE showed potent antibacterial activity against both oral pathogens but affected S.mutans stronger than P. gingivalis. The study indicates that MAEE might help prevent dental caries and periodontal diseases.