In vitro study of chemical compositions and antibacterial activity of Lorestan endemic plant, Pistacia atlantica leaf hydroalcoholic extract against cariogenic bacteria

Background and objectivesThe use of medicinal plants has been considered as an adjunctive treatment to prevent and control dental caries, alongside the mechanical removal of microbial agents. The aim of this study was to evaluate the chemical compositions and antibacterial activity of Pistacia atlantica leaf hydroalcoholic extract against standard strains of Streptococcus mutans (SM) and Lactobacillus rhamnosus (LR). Materials and MethodsThe hydroalcoholic extract of Pistacia atlantica leaves was prepared using the maceration method, and the chemical compositions were identified by a GC-MS apparatus. The antibacterial activity was assessed on the standard strains of SM and LR by measuring the mean diameter of the inhibition zone at different concentrations using the agar well diffusion method, and determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using the broth microdilution method. Chlorhexidine (CHX) mouthwash at a concentration of 0.2% was used as the positive control group. The tests were repeated three times, and the results were analyzed using ANOVA, Tukeys Honestly Significant Difference (HSD) test, and T-test with SPSS. A significance level of P< 0.05 was considered. ResultsThe MIC of the Pistacia atlantica leaf hydroalcoholic extract for SM, LR, and CHX was 12.5, 25, and 6.25 mg/ml, respectively, and the MBC for SM, LR, and CHX was 25, 25, and 6.25 mg/ml, respectively. In the agar well diffusion method, the mean diameter of the inhibition zone at the concentration of 200 mg/ml for SM, LR, and CHX was 23.33{+/-}6.50, 19.0{+/-}1.0, and 17.33{+/-}0.57 mm, respectively. The major chemical compositions were -pinene, -bisabolene, 3-hexenol, pulegone, and {beta}-pinene, respectively. ConclusionThe leaf hydroalcoholic extract of Pistacia atlantica demonstrated antibacterial activity against SM and LR.