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The objective of present investigation was to determine antimicrobial activity of Thymus vulgaris oil on some oral pathogens. Thymus vulgaris oil was prepared by hydrodistillation and tested against 30 clinical isolates of each of Streptococcus pyogenes, Streptococcus mutans, Candida albicans, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans, prepared from related oral infections using agar disk diffusion and broth microdilution methods. Thymus vulgaris oil at concentrations of 16 to 256 μg/mL exhibited strong inhibitory activity on all clinical isolates producing inhibition zones of 7.5 to 42 mm as measured by agar disk diffusion method. Streptococcus pyogenes and Streptococcus mutans were the most sensitive isolates with minimum inhibitory concentrations of 1.9 and 3.6 μg/mL, respectively. The minimum inhibitory concentration values for C albicans, A actinomycetemcomitans, and P gingivalis were 16.3, 32, and 32 μg/mL, respectively.

Garlic (Allium sativum) extract has been known to have inhibitory activity on various pathogenic bacteria, viruses and fungi. The objective of present investigation was to study in vitro inhibitory activity of garlic extract on multidrug-resistant (MDR) strains of Streptococcus mutans isolated from human carious teeth. Filter sterilized aqueous extract of garlic was prepared and used in the present study. For isolation of S. mutans, extracted human carious teeth were cultured in Todd-Hewit broth and Mitis-Salivarius-Bacitracin agar. S. mutans was characterized by colony morphology, biochemical tests and other conventional bacteriological procedures. Disk sensitivity tests and broth dilution methods were used to determine antibiotic sensitivity profile and inhibitory activity of garlic extract on S. mutans isolated from carious teeth. Of 105 carious teeth tested, 92 (87.6%) isolates of S. mutans were recovered, among which 28 (30.4%) were MDR since they were resistant to four or more antibiotics. The highest rate of resistance was observed for tetracycline (30.4%) and least resistance (0%) to teichoplanin and vancomycin while 22.8% and 23.9% of the isolates were resistant to penicillin and amoxicillin, respectively. Chlorhexidine minimum inhibitory concentration (MIC) for MDR and non-MDR S. mutans varied from 2 to 16 microg ml(-1) and from 0.25 to 1 microg ml(-1), respectively (P<0.05). All isolates, MDR and non-MDR of S. mutans were sensitive to garlic extract with the MIC ranging from 4 to 32 microg ml(-1). Considering in vitro data obtained in the present study, mouthwashes or toothpaste containing optimum concentration of garlic extract could be used for prevention of dental caries.

Objective: To determine the in vitro inhibitory activity of green tea extract on some clinically isolated cariogenic and periodontopathic bacteria. Materials and Methods: Twenty strains of each of Streptococcusmutans, Aggregatibacteractinomycetemcomitans, Porphyromonasgingivalis, and Prevotellaintermedia were isolated from carious teeth and periodontal pockets of patients with dental caries and periodontal diseases. Green tea extract was prepared by aqueous extraction method and diluted from 50 to 1.56 mg/ml. Standard techniques of agar disk diffusion and broth microdilution assays were applied for qualitative and quantitative determinations of antibacterial activity of green tea extract on each isolates. Results: All clinical isolates of S. mutans (100%) were sensitive to green tea extract at concentrations 6.25, 12.5, 25, and 50 mg/ml producing inhibition zones ranging from 10 to 38 mm. All periodontopathic isolates (A. actinomycetemcomitans, n = 20, P. intermedia, n = 20, and P. gingivalis, n = 20) (100%) tested were sensitive to 12.5, 25, and 50 mg/ml of this extract. The minimal inhibitory concentration of green tea extract for S. mutans was 3.28 ± 0.7 mg/ml and for A. actinomycetemcomitans 6.25, for P. gingivalis and P. intermedia 12.5 mg/ml. Conclusions: Our findings showed that green tea extract exhibited strong antibacterial activity on S. mutans,A. actinomycetemcomitans,P. gingivalis and P. intermedia and therefore may be used in mouthwashes or dentifrices for prevention of dental caries and periodontal diseases.

Background:Over the past two decades, there has been a growing trend in using oral hygienic products originating from natural resources such as essential oils (EOs) and plant extracts. Seven aromatic plants used in this study are among popular traditional Iranian medicinal plants with potential application in modern medicine as anti-oral infectious diseases.Objectives:This study was conducted to determine the chemical composition and antimicrobial activities of essential oils from seven medicinal plants against pathogens causing oral infections.Materials and Methods:The chemical compositions of EOs distilled from seven plants were analyzed by gas chromatography/mass spectrometry (GC/MS). These plants included Satureja khuzestanica, S. bachtiarica, Ocimum sanctum, Artemisia sieberi, Zataria multiflora, Carum copticum and Oliveria decumbens. The antimicrobial activity of the essential oils was evaluated by broth micro-dilution in 96 well plates as recommended by the Clinical and Laboratory Standards Institute (CLSI) methods.Results:The tested EOs inhibited the growth of examined oral pathogens at concentrations of 0.015-16 µL/mL. Among the examined oral pathogens, Enterococcus faecalis had the highest Minimum Inhibitory Concentrations (MICs) and Minimum Microbicidal Concentrations (MMCs). Of the examined EOs, S. khuzestanica, Z. multiflora and S. bachtiarica, showed the highest antimicrobial activities, respectively, while Artemisia sieberi exhibited the lowest antimicrobial activity.Conclusions:The excellent antimicrobial activities of the tested EOs might be due to their major phenolic or alcoholic monoterpenes with known antimicrobial activities. Hence, these EOs can be possibly used as an antimicrobial agent in treatment and control of oral pathogens.