Hamadan University of Medical Sciences Avicenna Journal of Dental Research 2423-7582 7 1 2015 06 01 An in Vitro Study on the Antibacterial Effect of Ferula Assa-Foetida L. and Quercus Infectoria Olivier Extracts on Streptococcus Mutans and Streptococcus Sanguis 4 4 10.17795/ajdr-22656 EN Mohammad Mehdi Fani Abdollah Bazargani Mohammad Ali Farboodniay Jahromi Zahra Hasanpour Khosrow Zamani Ehsan Yousefi Manesh Journal Article 10.17795/ajdr-22656 2014 08 09 2015 01 01 Background: From the ancient times, medicinal herbs have been regarded as efficient resources for the treatment of diseases. Among the diseases that can be treated by medicinal herbs, infectious diseases like oral ones are of notable importance. Objectives: The aim of this study was to evaluate the antibacterial effects of Ferula assa-foetida L (F. assa-foetida L.) and Quercus infectoria Olivier (Q. infectoria Olivier) aqueous and ethanolic extracts on Streptococcus mutans (S. mutans) and Streptococcus sanguis (S. sanguis). Materials and Methods: The studied plants were F. assa-foetida L. and Q infectoria Olivier. Their extracts with different concentrations of 100, 50, 25, 12.5, 6.25, and 3.125 mg/mL were prepared in culture medium, with well diffusion method, and, for control, their antibacterial effects were compared with chlorhexidine. For each extract, the antibacterial ability was determined based on the created inhibition zone diameter in the microbial culture medium. Results: The aqueous and ethanolic extract of F. assa-foetida L. lacked the inhibitory effect against the growth of S. mutans and S. sanguis bacteria. There was a significant difference among the inhibitory zones created by dissimilar concentrations of Q. infectoria (P = 0.025). Also, the aqueous and ethanolic extracts’ minimum inhibitory concentration (MIC) for S. mutans bacterium was calculated to be 12.5 mg/ mL, while its value for S. sanguis bacterium was 6.25 mg/mL. Conclusions: The results of our study, regarding the observed effects based on differences in concentrations, suggest that further and more comprehensive studies should be undertaken to determine the appropriate concentration for obtaining the effect of the extract of F. assa-foetida L. and Q infectoria Olivier on S. mutans and S. sanguis