Effect of hydroalcoholic extracts leaves Myracrodruon urundeuva all. and Qualea Grandiflora Mart. on viability of Streptococcus mutans biofilm and prevention of enamel demineralization in vitro

• Grant number: 16/20212-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): February 01, 2017
• Effective date (End): December 31, 2017
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Ana Carolina Magalhães
• Grantee: Sara Salustiano Zabini
• Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil

Abstract

Dental caries is a disease related to the presence of a biofilm rich in cariogenic bacteria, as well as to the high consumption of carbohydrates, mainly sucrose. Streptococcus mutans is considered the most important bacteria related to tooth decay. Therefore, the inhibition of S. mutans growth by alternative antimicrobial agents has been investigated in an attempt to obtain an agent with a wide effectiveness and without side-effects. Taking into account the phytotherapy studies and the high prevalence and impact of dental caries, it may be interesting to test the effect of Myracrodruon urundeuva and Qualea grandiflora on S. mutans. Therefore, the present study aims to: 1) determine the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), minimum biofilm inhibitory concentration (MBIC) and minimum biofilm eradicating concentration (MBEC) of these two isolated or combined natural agents, 2) test the effect of the concentrations (MIC, MBC, MBIC and MBEC) on the viability of S. mutans biofilm and 3) test the effect of the concentrations on the prevention of enamel demineralization. Strain of S. mutans (ATCC 21175) will be reactivated in agar mitis salivarius. The MIC and MBIC will be determined by seriate dilution method using microplates and the extracts will be evaluated at concentrations ranging from 0.00195 to 1.00 mg/ml. As positive control, we will apply 0.12% chlorhexidine and as negative controls, PBS and 35% alcohol. The MIC and MBIC will be defined as the lowest concentration of the antimicrobial agent capable of inhibiting 50 to 90% the microbial growth and viability compared to the negative controls, respectively. For MBC determination, aliquots of the MIC will be removed from wells that don't show any absorbance (growth) and plated on BHI agar plates supplemented with 1% sucrose and incubated for 24h, at 37° C and 5% CO2. Viable cells will be counted and the MBC determined considering the lowest concentration of the extracts able to prevent the visible bacterial growth. For the MBEC experiment, the bacteria will be cultivated for 24 h and, then, expose directly to the extracts for further 24 h. The viability will be determined similarly to MBIC. For the formation of biofilm, bovine enamel samples will be prepared and S. mutans colonies will be diluted in artificial saliva McBain (1:50) and used for the colonization. The medium exchange and the treatments (at the concentrations specified above, 1x60s/day) will be done daily for a period of 7 or 14 days according to a pilot study. The live and dead bacteria (%) will be evidenced by fluorescence using confocal microscopy. Enamel demineralization will be measured using transversal microradiography. The data will be submitted to the statistical analysis (p <0.05). (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

PIRES, JULIANA GONCALVES; ZABINI, SARA SALUSTIANO; BRAGA, ALINE SILVA; FABRIS, RITA DE CASSIA; DE ANDRADE, FLAVIANA BOMBARDA; DE OLIVEIRA, RODRIGO CARDOSO; MAGALHAES, ANA CAROLINA. Hydroalcoholic extracts of Myracrodruon urundeuva All. and Qualea grandiflora Mart. leaves on Streptococcus mutans biofilm and tooth demineralization. ARCHIVES OF ORAL BIOLOGY, v. 91, p. 17-22, JUL 2018. (17/00556-0, 16/20212-0)