EFFECT OF OCIMUM BASILICUM OIL EXTRACT ON STREPTOCOCCUS MUTANS AND STREPTOCOCCUS SOBRINUS BIOFILM FORMATION

Kemthong Mitrakul1, Ratchapin Srisatjaluk2, Pattamapan Lomarat3 and Theerachai Kosanwat4

Abstract

Streptococcus mutans and Streptococcus sobrinus are associated with plaque formation and caries development. The aims of this study were to evaluate the ability of the extract of Ocimum basilicum oil to inhibit the growth and biofilm for-mation produced by Streptococcus mutans (ATCC 25175) and Streptococcus sobrinus (ATCC 6715) and 3 S. mutans isolates obtained clinically from Thai children in order to determine its potential usefulness for future clinical studies. Three concentra-tions of O. basilicum extract were used for the study (6%, 8%, and 10%). Bacterial inhibition was tested by an agar inhibition assay. Biofilm inhibition was tested by a biofilm formation assay in a 96-well polystyrene plate. The positive and nega-tive controls were 0.12% chlorhexidine mouthrinse and 95% ethanol, respectively. Oil extract penetration was determined by fluorencent staining and visualization under confocal laser scanning electron microscopy (CLSM). All tested extracts had greater inhibition of tested bacterial isolates than controls. All extract concentrations inhibited biofilm formation of all isolates examined. The CLSM examination of S. mutans (ATCC 25175) showed the 6% extract had the greatest biofilm penetration and inhibition, followed by the 8% and 10% concentrations. The CLSM examination of S. sobrinus (ATCC 6715) showed the 8% extract had the greatest biofilm penetration and inhibition, followed by the 10% and 6% concentrations. All extract concentra-tions caused significantly (p=0.005) greater inhibition of S. mutans, S. sobrinus and other tested clinical isolates than the control group. O. basilicum essential oil appears to be a good candidate for future clinical studies.