Antimicrobial inhibitory activity of aqueous, hydroalcoholic and alcoholic extracts of leaves and stem of Daphne mucronata on growth of oral bacteria

Background: Plants are a source of potential anti-infective agents. Daphne mucronata is a shrub in the family Thymelaeaceae, which has therapeutic effects. The aim of the present study was to evaluate the antimicrobial activity of aqueous, hydroalcoholic and alcoholic extracts of the leaves and stem of Daphne mucronata on the growth of oral bacteria. Materials and methods: Leaves and stem of Daphne mucronata were collected from the Zagros Mountains, Lorestan, Iran. They were air dried in the shade. Aqueous, hydroalcoholic and alcoholic extracts of Daphne mucronata were made by using classic techniques for solvent extraction of plant material. The antimicrobial effects of the Daphne mucronata extracts were evaluated using the agar disk diffusion method (ADDM) and the minimum inhibitory concentration (MIC). The data were analyzed using Duncan's test and ANOVA. Results: The results showed that the antimicrobial activity depended on the type of extract. The alcoholic extract of Daphne mucronata had the highest antibacterial activity and the highest effect on Streptococcus mutans. The aqueous extract of the plant had no effect on bacterial growth. Conclusion: On the basis of the current results, the alcoholic extract of Daphne mucronata might be promising as a natural antimicrobial agent and as a medicine for the prevention and control of the growth of Streptococcus mutans.