title: Evaluation of biofilm removal activity of Quercus infectoria galls against Streptococcus mutans.
abstract: BACKGROUND
  Dental caries is one of the most prevalent infectious diseases affecting humans of all ages. Streptococcus mutans has an important role in the development of dental caries by acid production. The purpose of this study was to evaluate the antibacterial and biofilm disinfective effects of the oak tree Quercus infectoria galls against S. mutans.
  
  
  METHODS
  The bacterial strain used in this study was S. mutans (ATCC: 35668). Two kinds of galls, Mazouj and Ghalghaf were examined. Galls were extracted by methanol, ethanol and acetone by Soxhlet apparatus, separately. Extracts were dissolved in sterile distilled water to a final concentration of 10.00, 5.00, 2.50, 1.25, 0.63, 0.31, and 0.16 mg/ml. Microdilution determined antibacterial activities. The biofilm removal activities of the extracts were examined using crystal violet-stained microtiter plate method. One-way ANOVA was used to compare biofilm formation in the presence or absence of the extracts.
  
  
  RESULTS
  The methanolic, ethanolic, and acetonic extracts of Q. infectoria galls showed the strong inhibitory effects on S. mutans (P < 0.05). The minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values for the Mazouj and Ghalghaf gall extracts against S. mutans were identical. The MIC values ranged from 160 μg/ml to 320 μg/ml, whereas the MBC values ranged from 320 μg/ml to 640 μg/ml. All extracts of Q. infectoria galls significantly (P < 0.05) reduced biofilm biomass of S. mutans at the concentrations higher than 9.8 μg/ml.
  
  
  CONCLUSIONS
  Three different extracts of Q. infectoria galls were similar in their antibacterial activity against S. mutans. These extracts had the highest biofilm removal activities at 312.5 μg/ml concentration. The galls of Q. infectoria are potentially good sources of antibacterial and biofilm disinfection agent.
authors.affiliation: Department of Microbiology, Falavarjan Branch, Islamic Azad University, Isfahan, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Mohammadi-Sichani
authors.affiliation: Department of Microbiology, Falavarjan Branch, Islamic Azad University, Isfahan, Iran.
authors.forename: Vajihe
authors.initials: V
authors.lastname: Karbasizadeh
authors.affiliation: Young Researchers and Elite Club, Falavarjan Branch, Islamic Azad University, Isfahan, Iran.
authors.forename: Samaneh Chaharmiri
authors.initials: SC
authors.lastname: Dokhaharani
keywords: Biofilm removal activity; Streptococcus mutans; dental plaque; oak gall; plant extracts