Coleus blumei extract as a potential antibacterial oral rinse

Abstract

Commercially available oral rinses, containing chlorhexidine are effective in treating and preventing oral infections but they can cause unpleasant taste and staining of teeth and are not advocated for long- term oral care. Hence comes the need for an alternative remedy with reduced side effects that is suitable for daily regime. Coleus blumei has been reported to contain phytochemicals that are active against oral bacteria. The objective of this study is to determine the phytochemicals content of C. blumei leaves extract and its potential as an antibacterial agent to treat oral infection as alternative to chlorhexidine. C. blumei extract was first screened for its phytochemicals content and was later screened for its antibacterial activity against Staphylococcus aureus and Streptococcus mitis using disc diffusion method. The extract was tested to find the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) for both bacteria. The phytochemicals screenings showed that the extract contains flavonoid, terpenoid, tannin and saponin. At a concentration of 100 mg/ml, the extract showed antibacterial activity against both bacteria, S. aureus (14.56 mm) and S. mitis (13 mm), with Percentage of Relative Inhibition Zone Diameter (% RIZD) of 35% (S. aureus) and 65% (S. mitis). The extract was shown to have similar effects as Oradex oral rinse (0.12% chlorhexidine), with 15.67 mm inhibition zone and % RIZD of 38% for S. aureus, and 15mm with % RIZD of 75% for S. mitis. The MIC results shows that the extract was most effective against S. aureus, as the MIC was determined at the lowest concentration of 1.5625 mg/ml and the MBC was determine at the concentration of 100 mg, 50 mg/ml, 25 mg/ml, 12.5 mg/ml, 6.25 mg/ml and 3.125 mg/ml. For S. mitis, the MIC was determined at the concentration of 25 mg/ml, with MBC value at the highest concentration of 100 mg/ml. These results suggest that C. blumei extract possesses antibacterial effects against oral bacteria similar to Oradex and therefore has the potential to be used as an oral rinse in the future.