Antibacterial activity of ethanolic extract of Myrtus communis. L leaves against salivary Mutans streptococci

The aim of this study was to evaluate the efficacy of ethanolic extract of Myrtus communis (myrtle) leaves in the selective reduction of Mutans streptococci count in saliva compared to chlorhexidine through in vitro and in vivo experiments. Ethanolic extract (2%) was prepared and screened by UV-visible spectrophotometer to detect peaks of active compounds. The minimum inhibitory concentrations (MICs) of myrtle extract as well as chlorhexidine (0.12%) were determined against Mutans streptococci isolated from human saliva and identified bacteriologically in vivo experiments, the effect of single mouth rinse of myrtle extract or chlorhexidine was investigated against the number of colony forming unit (CFU) of Mutans streptococci for two hours after rinse. The results showed the presence of one large peak at λ266.5 nm and a small one at λ672 of the extract in UV-visible spectra suggesting the presence of flavanoid. The MIC of myrtle was 106.6 μg/mL compared with 3.3 μg/mL of chlorhexidine. Single mouth rinse of myrtle extract significantly reduced the number of CFU of salivary Mutans streptococci but its effect was significantly less than that of chlorhexidine. It was concluded that the antibacterial effect of myrtle on Mutans streptococci was due to its flavanoid content. Therefore, ethanolic extract of myrtle could be a potential remedy for the prevention of colonization by Mutans streptococci thereby preventing or retarding development of dental caries. (author)