In vitro Cariostatic effects of cinnamon water extract on nicotine-induced Streptococcus mutans biofilm

Abstract Background Dental caries is one of the most prevalent chronic oral diseases worldwide. Dental caries is mainly associated withStreptococcus mutansand theLactobacillusspecies. A specific relationship was found between nicotine andS. mutansgrowth as the presence of nicotine increasedS. mutansbiofilm formation. Nicotine is able to increase the number ofS. mutansand extracellular polysaccharide (EPS) synthesis. Among the widely used herbs and spices is cinnamon which demonstrated a strong antibacterial activity against a wide variety of bacteria includingS. mutansand showed the ability to inhibitS. mutansbiofilm formation. Cinnamon essential oil, obtained from the leaves ofC. zeylanicum, has been demonstrated to be effective againstS. mutansandLactobacillus acidophilus, which are partially responsible for dental plaque formation and caries development. The aim of this study was to identify the effects of nicotine exposure on the inhibitory effects of cinnamon water extract onS. mutansbiofilm formation. Materials and methods A 24-h culture ofS. mutansUA159 in microtiter plates was treated with varying nicotine concentrations (0–32 mg/ml) in Tryptic Soy broth supplemented with 1% sucrose (TSBS) with or without a standardized concentration (2.5 mg/ml) of cinnamon water extract. A spectrophotometer was used to determine total growth absorbance and planktonic growth. The microtiter plate wells were washed, fixed and stained with crystal violet dye and the absorbance measured to determine biofilm formation. Results The presence of 2.5 mg/ml cinnamon water extract inhibits nicotine-inducedS. mutansbiofilm formation from 34 to 98% at different concentrations of nicotine (0–32 mg/ml). Conclusion The results demonstrated nicotine-inducedS. mutansbiofilm formation is decreased from 34 to 98% in the presence of 2.5 mg/ml cinnamon water extract. This provides further evidence about the biofilm inhibitory properties of cinnamon water extract and reconfirms the harmful effects of nicotine.