Anti-microbial activity and biofilm inhibition of Streptococcus mutans by Coriandrum sativum essential oil and isothiocyanates

Abstract

AbstractAims This study evaluated the antimicrobial effect of coriander oil (CO) and isothiocyanates (ITC; Allyl, Benzyl and Phenyl-A-, B-, P-ITC) on clinical oral isolateStreptococcus mutans. We evaluated inhibition of biofilm, metabolic activity and exopolysaccharide formation. Methods The composition of CO was determined by gas chromatography- mass spectrometry (GC-MS). CO and ITC were dissolved in 0.1% Tween 80. Different concentrations (0.0039-1%) of CO, ITC and CO-ITC were made in Tryptic soy broth (TSB) and with sucrose (TSBS). Broth dilution method was used to determine the minimum inhibitory concentration (MIC). Minimum biofilm inhibitory concentrations (MBIC) were established by staining biofilm with crystal violet. Checkerboard assay was used to evaluate combination effects. An XTT assay was used to determine the metabolic activity and a sulphuric acid-phenol assay for inhibition ofS. mutansexopolysaccharide production. Results CO was dominated by Linalool (65.5%) followed by 2-bornanone (6.16%) and Gamma-terpinene (4.31%). The least was Terpinen-4-ol (0.13%). The MIC of CO was 0.00195% and < 0.00195% for ITCs. MBIC for B-ITC was at < 0.0039%, while with CO-ITC at 0.00195% (p < 0.05). The MBC of CO was 0.125% and for CO-B-ITC MBIC was < 0.00195%. The B-ITC MBC was > 0.25%. StrongS. mutansexopolysaccharide inhibition was observed with ITC and CO at 0.0039%. CO reducedS. mutansmetabolic activity at 0.125% and ITC at 0.0078%. Conclusion and clinical relevance: CO and ITC are promising agents in prevention of both periodontal disease and dental caries. Further data is required to warrant development of products to help mitigate dental caries and periodontal disease.