The antimicrobial and antibiofilm effects of three herbal extracts on Streptococcus mutans compared with Chlorhexidine 0.2% (in vitro study)

Abstract

There is a special focus on using natural materials and herbal plants to prevent dental caries. Previous studies showed that some herbal plants have antimicrobial effects on oral pathogens. Thus we investigated the antimicrobial effects of three herbal extracts (Carum copticum, Phlomis bruguieri, and Marrubium parviflorum) on the growth of Streptococcus mutans, as the most important bacteria causing dental caries. First, plant methanolic extracts were prepared. Then, to evaluate the antimicrobial activity of the three herbal extracts, the agar well diffusion method and MIC were performed. The biofilm formation was carried out using a broth dilution method with 2% glucose-supplemented BHIS in sterile 96-well microplates. Serial dilutions (50, 25, 12.5, 6.25, 3.12 mg/ml) of extracts were prepared. Next, a 0.5 McFarland Suspension of S. mutans was added to wells. The inhibitory effect on biofilm formation was measured by the ELISA reader apparatus. The assay was repeated three times, and the average was calculated as 3. The results were compared with those of Chlorhexidine 0.2%. Carum copticum showed a better effect in the agar well diffusion method than others. MIC of the extracts of Carum coptimum, Phlomis bruguieri, and Marrubium parviflorum were 3.12, 6.25, and 12.5 mg/ml, respectively. Overall, the highest activity belonged to Carum copticum extract. For the anti-biofilm effect, the OD values of Carum copticum and Marrubium parviflorum were significantly different from that of Phlomis bruguieri. Although all of the methanolic herbal extracts can inhibit S. mutans growth and remove the biofilm, the effect of Carum copticum was better than Phlomis bruguieri and Marrubium parviflorum. Further studies are recommended to indicate how these extracts perform against the bacteria.

The effect of mindfulness-based stress reduction (MBSR) training on serum cortisol levels, depression, stress, and anxiety in type 2 diabetic older adults during the COVID-19 outbreak

“…Moreover, Anderson et al examined the impact of mindfulness on depression, reducing anger rumination, and increasing concentration and attention in life in 68 adults. Contrary to the present work, the researchers reported insignificant differences between the intervention and the control groups [ 37 – 39 ].…”

Plant-Derived Compounds: A Promising Tool for Dental Caries Prevention

“…Based on the inclusion and exclusion criteria, a total of 31 studies are presented and analyzed in this comprehensive review. Table 1 records the in vitro studies conducted from 2019 until 2024 [ 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 ], and Table 2 analyzes the in vivo, in situ, and ex vivo clinical studies available in the literature [ 74 , 75 , 76 , 77 , 78 , 79 ]. In both tables, extensive descriptive information on the aim of the study (objectives), the type of experimental and control groups used, the methodological pattern followed, the bacterial strains chosen, and the results that emerged is present.…”

Antagonistic, synergistic, and additive antibacterial interaction between ciprofloxacin and amoxicillin against Staphylococcus aureus

“…This in vitro study evaluated the antibacterial interaction of the ciprofloxacin-amoxicillin combination versus S. aureus using the agar well diffusion technique, isobolographic statistical method, and the interaction index. The agar well diffusion method is widely used and accepted to determine the antimicrobial effect of drugs and natural extracts [12,13,[19][20][21][22]. S. aureus showed high susceptibility to ciprofloxacin.…”