Comparison of Antibacterial Effect of Hydroalcoholic Extract of Four Plants against Cariogenic Microorganisms by two in Vitro Methods

Caries is a multifactorial disease with a microbial nature. Thus, more concentration on its operative treatment will lead to failure in annihilating its origin. On the other hand, because of known side effects of antibiotics and world attraction to traditional treatment and importance of drug extraction of natural material and plants, this study was done to compare the antibacterial effect of hydroalcoholic extract of Salvia officinalis, Pimpinella anisum, Mentha longifolia and Achillea millefolium against Streptococcus mutans, Lactobacillus rhamnosus and Actinomyces viscosus with two in vitro methods. In this experimental study, hydroalcoholic extracts have been prepared from Salvia officinalis, Pimpinella anisum, Mentha longifolia and Achillea millefolium with maceration method. Their antibacterial activity against Streptococcus mutans, Lactobacillus rhamnosus and Actinomyces viscosus have been evaluated with Broth macrodilution (the method in which amounts of antimicrobial agents is diluted in broth environment serially) (0.18-200 µg/ml) and Agar diffusion (the method in which antimicrobial effect is assessed in solid environment) (0.78-400 µg/ml) methods. In Broth macrodilution method MIC (Minimum Inhibitory Concentration) for Pimpinella anisum, Salvia officinalis, Mentha longifolia and Achillea millefolium for Streptococcus mutans were respectively 12.5, 6.25, 12.5 and 50 µg/ml, for Lactobacillus rhamnosus 12.5,1.56, 3.12 and 12.5 µg/ml and for Actinomyces viscosus 50, 12.5, 100 and 50 µg/ml. In Agar diffusion method Pimpinella anisum and Salvia officinalis against Streptococcus mutans, Pimpinella anisum against Lactobacillus rhamnosus and Mentha longifolia against Actinomyces viscosus had antibacterial effect. According to the results of this study, four extracts had growth inhibitory effect on all three bacteria. Salvia officinalis had greater effect on inhibition of growth of all three bacteria. All of the extracts had bactericidal effect in the range of concentration