In vitro study of the effects of honeysuckle on Streptococcus mutans UA159 / 口腔疾病防治

Objective@# To investigate the inhibitory effect of honeysuckle on Streptococcus mutans UA159 in vitro.@*Methods@# We used a double-dilution method to measure the minimum inhibitory concentration (MIC) of honeysuckle against Streptococcus mutans UA159. Lonicerae lonicerae powder was dissolved in the solvent DMSO, different concentrations of liquid medicine were prepared, and bacterial liquid was added. The solution control group and bacterial liquid control group were set at the same time. The growth and acid production of UA159 were determined using antibacterial experiments. A growth curve and acid production curves were drawn, and the adhesion rate and adhesion inhibition rate were calculated. The effect of honeysuckle on the formation of Streptococcus mutans UA159 was determined by crystal violet quantification, and a microscope and a scanning electron microscope were used to observe biofilm formation and structural changes.@* Results @# The MIC of honeysuckle against Streptococcus mutans UA159 was 12.5 mg/mL. The bacteriostatic experiments showed a difference in the growth, acid production and adhesion of UA159 after honeysuckle treatment (P<0.05) compared with the controls, and the inhibitory effect increased as the drug liquid concentration increased. Crystal violet quantification showed a significant difference in biofilm formation between the pharmaceutical liquid group and the control group (P<0.05). Meanwhile, the forward microscope showed a significant decrease in biofilm formation. Under SEM, the number of bacteria decreased significantly at 0, 6 and 12 h after honeysuckle addition. @*Conclusion @# Honeysuckle inhibits the growth and acid production of UA159 and inhibits adhesion and the formation of biofilms.

Inhibitory effect of baicalin on Streptococcus mutans UA159 in vitro / 口腔疾病防治

Objective @# To investigate the inhibitory effect of baicalin on Streptococcus mutans UA159 in vitro.@*Methods @#The minimum inhibitory concentration (MIC) of baicalin on Streptococcus mutans UA159 was determined by the liquid multiple dilution method combined with the OD600 value measured by microplate. The OD600 value of Streptococcus mutans UA159 in different concentrations of baicalin was measured by an enzyme mapping instrument. A growth curve was drawn, and the adhesion rate and adhesion inhibition rate were calculated. The effect of baicalin on the formation of Streptococcus mutans UA159 biofilms was observed by the crystal violet quantitative method and scanning electron microscopy. The effect of baicalin on the total number of Streptococcus mutans UA159 bacteria was observed by scanning electron microscopy.@*Results@#The MIC of baicalin on Streptococcus mutans UA159 was 12 mg/mL. With increasing baicalin concentration, the growth rate of Streptococcus mutans UA159 was slowed, the adhesion rate of Streptococcus mutans UA159 decreased and the adhesion inhibition rate increased（P < 0.05）. The results of crystal violet quantitative method showed that compared with the bacterial control group, the biofilm formation of Streptococcus mutans UA159 was significantly reduced after adding baicalin at 0 h, 6 h and 12 h (P < 0.001). Under a scanning electron microscope, the total number of bacteria decreased significantly after adding baicalin at 0 h, 6 h and 12 h.@*Conclusion@# baicalin ; natural medicine ; Streptococcus mutans UA159 ; caries ; minimum inhibitory concentration ; growth curve ; adhesion rate ; adhesion inhibition rate ; biofilm formation ; in vitro study

Oleanolic acid and ursolic acid inhibit peptidoglycan biosynthesis in Streptococcus mutans UA159

In this study, we revealed that OA and UA significantly inhibited the expression of most genes related to peptidoglycan biosynthesis in S. mutans UA159. To the best of our knowledge, this is the first report to introduce the antimicrobial mechanism of OA and UA against S. mutans.

Estudo in vitro da atividade do extrato etanólico de sementes de bacupari (Rheedia gardneriana Planch. & Triana) e das frações no crescimento de Streptococcus mutans / In vitro study of the activity of ethanol extract from bacupari (Rheedia gardneriana Planch. & Triana) seeds and its fractions on Streptococcus mutans growth

Streptococcus mutans, principal microrganismo da cavidade oral, desempenha papel preponderante na formação de placas dentárias, sendo considerado o agente etiológico primário da cárie. Rheedia gardneriana, conhecida popularmente como bacupari, é uma planta utilizada com fins medicinais para o tratamento de diversas patologias, e por apresentar atividade antimicrobiana de compostos das folhas contra bactérias Gram-positivas e Gram-negativas. O objetivo do presente trabalho foi avaliar o efeito de extrato de semente de R. gardneriana sobre a cepa S. mutans UA159. Os testes foram conduzidos com o extrato etanólico bruto e as frações obtidas com os solventes diclorometano, etanol-água, metanol e hexano, em ensaios de inibição in vitro. O extrato bruto (100 por cento) apresentou halos de inibição com diâmetro similar ao obtido com solução de digluconato de clorexidina 0,12 por cento, usada como controle. Os ensaios com a fração diclorometano exibiram atividade inibitória 35 por cento menor comparado com o controle, enquanto nenhum efeito antimicrobiano foi observado com a fração etanol-água. Contrariamente, os resultados obtidos com as frações hexânica e metanólica demonstraram claramente a atividade antimicrobiana por inibição do crescimento bacteriano. Na fração metanólica a formação de halos de inibição foi similar ao do controle. Estes dados apresentam atividade antimicrobiana de R. gardneriana contra S. mutans.

Streptococcus mutans, which is the main microorganism of the oral cavity, plays a preponderant role in dental plaque formation and is considered the primary etiologic agent regarding caries. Commonly known as "bacupari", Rheedia gardneriana is a plant used for medicinal purposes in the treatment of several pathologies; besides, its leaves have compounds that present antimicrobial activity against Gram-positive and Gram-negative bacteria. The aim of this work was to evaluate the effect of R. gardneriana seed extract on S. mutans strain UA159. The tests were carried out with crude ethanol extract and the fractions obtained with the solvents dichloromethane, ethanol-water, methanol, and hexane in in vitro inhibition assays. The crude extract (100 percent) presented inhibition halos with diameter similar to that obtained by using 0.12 percent chlorhexidine digluconate solution as control. Assays with the fraction dichloromethane showed an inhibitory activity 35 percent lower than that of the control, whereas no antimicrobial effect was observed with the ethanol-water fraction. Conversely, the results obtained with the fractions hexane and methanol clearly demonstrated antimicrobial activity by inhibiting the bacterial growth. In the methanol fraction, the formation of inhibition halos was similar to that in the control. These data present antimicrobial activity of R. gardneriana against S. mutans.