EVALUATION OF THE ANTI-CARIES EFFECT OF LESPEDEZA CUNEATA EXTRACT AGAINST STREPTOCOCCUS MUTANS.

The purpose of this study was to identify the antimicrobial activity of Lespedeza cuneata extract, a natural medicine, against a main causative bacterium of dental caries, Streptococcus mutans (S. mutans). Lespedeza cuneata purchased from Hwalim Natural Drug Co., Ltd. (Busan, South Korea) was immersed in 70% ethanol for 12 h, and concentrated Lespedeza cuneata extract was applied to S. mutans diluted to 6×105 CFU/mL at the concentrations of 0, 1.25, 2.5, 5, 10, 20, and 40 mg/ml. Then the colony-forming units (CFUs) were checked at 6 and 24 h to evaluate the antimicrobial activity of the extract. The CFUs and survival rate of S. mutans according to the concentration showed a higher mortality rate as the concentration of Lespedeza cuneata extract increased. In the time-dependent changes, the minimal inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) were 1.25 and 40 mg/mL or more, respectively, at 6 h, but they were 1.25 and 5 mg/mL, respectively, at 24 h. Therefore, Lespedeza cuneata extract is considered an excellent natural antibiotic for the prevention and treatment of dental caries, a typical oral disease, because it has excellent dental caries development suppression and bacteria extermination effects.

Feasibility of nonthermal atmospheric pressure plasma for intracoronal bleaching.

AIM: To investigate the effect of nonthermal atmospheric pressure plasma on intracoronal tooth bleaching in blood stained human teeth. METHODOLOGY: Forty extracted single-root and blood stained human teeth were used. The teeth were randomly divided into two groups (n=20): group 1 received 30% HP activated by nonthermal atmospheric pressure plasma in the pulp chamber for 30 min, whilst group 2 received 30% HP alone in the pulp chamber for 30 min. The overall colour changes (ΔE) were assessed using the Commission Internationale de L'Eclairage (CIE) Lab Colour System. The data were analysed using Student's t-test to determine the significant differences. RESULTS: The temperature of all teeth was maintained at approximately 37 °C during plasma bleaching. The plasma treatment with 30% HP resulted in significantly higher bleaching efficacy compared to 30% HP alone in discoloured teeth (P<0.05). The average ΔE values of group 1 and group 2 were 9.24 (0.37) and 4.47 (1.62), respectively, at 30 min. CONCLUSIONS: The application of nonthermal atmospheric pressure plasma to intracoronal bleaching could be a novel and efficient therapy in the bleaching of haemorrhagically stained teeth.

Bran extracts from pigmented rice seeds inhibit tumor promotion in lymphoblastoid B cells by phorbol ester.

Using flow cytometry, we quantitatively evaluated anti-tumor-promoting activity of rice bran extracts by measuring inhibition of Epstein-Barr virus early-antigen activation (EBV-EA) induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). This assay measures anti-tumor-promoting activity and cytotoxicity of target substances using the same batch of cells. Using this short-term procedure, we have determined the anti-tumor-promoting activity of 70% ethanol-water extracts of bran (outer layer) from seeds of five pigmented rice cultivars: Jumlalocal-1, DZ 78, Elwee, LK1-3-6-12-1-1, and LK1A-2-12-1-1. The results show that, compared to an extract from the non-pigmented white cooking rice variety Chuchung, the extracts from the pigmented varieties strongly inhibited phorbol ester-induced tumor promotion in marmoset lymphoblastoid cells B95-8 in vitro. These findings may facilitate development and use of new health-promoting rice varieties.