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Oral streptococci are the major group of bacteria in the oral cavity. Some of their species cause oral diseases that may lead to tooth loss and quality-of-life reduction, such as dental caries. One of prevention techniques to promote oral health is rinsing mouthwash after toothbrushing. This study aimed to determine the potential uses of local food, also remedy, plant in Thailand called Reaw-Horm or Etlingera pavieana for alternative herbal mouthwash. The essential oil from E. pavieana rhizome (Eo) is used for anti-streptococci including Streptococcus mutans and Streptococcus sobrinus and anti-biofilm activities. The main components of Eo are methyl chavicol (MC) and trans-anethole (TA). The disk diffusion method showed the inhibition zone of Eo in a dose-dependent manner. The minimum inhibitory concentration (MIC) of Eo and TA was >1.6 % v/v, and 0.4 % v/v of MC. Regarding anti-biofilm activities, MC showed nearly equal anti-biofilm formation of S. mutans and S. sobrinus, whereas Eo and TA acted toward S. sobrinus more than S. mutans biofilm. Sub-MIC killing effects on cells under biofilm were observed in Eo and MC. Therefore, MC was recommended as an active compound for anti-streptococci activities. Biocompatibility of Eo and MC were shown to be safe for epidermal cell lines. Herbal mouthwashes containing Eo were developed and had antioxidant and antimicrobial actions with established for 3 months. This study provides in vitro support on the use of herbal mouthwash with antioxidant and antimicrobial activities for dental caries prevention and well-being of individuals.

Abstract Bone cancer has traditionally been treated using surgery, radiotherapy, and/or chemotherapy. The nonspecific distribution of chemotherapy and implantable infections are significant risk factors for the failure of the bone to heal. Multifunctional zinc and silver co-doped bioactive glass nanoparticles (yAg–xZn-BGNPs) with a diameter of 150 ± 30 nm were successfully synthesized using modified sol–gel and two-step post-functionalization processes, tailored to provide antibacterial and anticancer activity whilst maintaining osteogenesis ability. Co-doped BGNPs with Zn and Ag did not significantly alter physicochemical properties, including size, morphology, glass network, and amorphous nature. Apatite-like layer was observed on the surface of yAg–xZn-BGNPs and resorbed in the simulated body fluid solution, which could increase their bioactivity. Human fetal osteoblast cell line (hFOB 1.19) treated with particles showed calcified tissue formation and alkaline phosphatase activity in the absence of osteogenic supplements in vitro, especially with 0.5Ag–1Zn-BGNPs. Moreover, these particles preferentially disrupted the metabolic activity of bone cancer cells (MG-63) and had an antibacterial effect against B. subtilis, E. coli, and S. aureus via the disc diffusion method. This novel 0.5Ag–1Zn-BGNP and 1Ag–1Zn-BGNPs, with wide-ranging ability to stimulate bone regeneration, to inhibit bone cancer cell proliferation, and to prevent bacterial growth properties, may provide a feasible strategy for bone cancer treatment. The 0.5Ag–1Zn-BGNPs and 1Ag–1Zn-BGNPs can be applied for the preparation of scaffolds or filler composites using in bone tissue engineering.

Streptococcus mutans is a well-known oral pathogen commonly associated with a normal dental problem and life-threatening infection. A bacteriocin nisin and the plant-derived compounds including gallic acid (GA) and Thai culinary essential oils (EOs) have been reported to have activity against oral pathogens. However, their synergistic interaction against S. mutans has not been explored. The purposes of this study were primarily to investigate anti-S. mutans properties and the antibiofilm formation of nisin, GA, and five EOs by using the broth microdilution method. Besides, the morphological change, killing rate, and antibacterial synergism were determined by scanning electron microscopy (SEM), time-kill assay, and checkerboard method, respectively. The results demonstrated that kaffir lime leaf (KLL) oil, lemongrass (LG) oil, and GA showed a potent anti-S. mutans activity and inhibited biofilm formation with the possible mechanism targeted on the cell membrane. Additionally, KLL oil revealed anti-S. mutans synergism with GA, LG oil, and chlorhexidine with the fractional inhibitory concentration (FIC) indexes ≤ 0.5. Interestingly, GA displayed a high potential to enhance anti-S. mutans activity of nisin by lowering the minimum inhibitory concentrations (MICs) to at least 8-fold in a bacteriostatic manner. These results suggest that GA and KLL oil may be potentially used as an adjunctive therapy along with nisin and chlorhexidine to control S. mutans infection.