Background: Stevioside is a natural herbal sweetener extracted from Stevia rebaudiana. An in vitro study has proved the antibacterial efficacy of 0. 2% Stevia aqueous solution against Streptococcus mutans and Lactobacillus acidophilus, and the present study was conducted to clinically evaluate the efficacy of Stevia leaf extract and Stevia product on plaque pH, when compared with sucrose solution. Materials and Methods: A clinical trial was conducted among a sample of 22 undergraduate students who volunteered. After obtaining consent, students were instructed not to brush at night and not to use any mouth rinse during the course of the study. Baseline plaque pH was measured in situ using digital pH meter. Students were asked to rinse for 1 min with 0. 2% aqueous solution of Stevia leaf extract and plaque pH was measured in situ at 4 time points (5, 10, 15, and 30 min) after each rinse. After a washout period of 2 days, 10% sucrose and 1% Stevia product solutions were similarly tested. Statistical analysis was performed using analysis of variance (ANOVA) test and repeated measures ANOVA. Tukey’ s HSD test was used to obtain multiple comparisons. The level of significance was set to be at P < 0. 05. Results: At 5, 10, 15, and 30 min, a significant difference in mean plaque pH values was observed between three test solutions (P < 0. 000). Post hoc Tukey’ s HSD test showed that the difference in mean pH values between aqueous Stevia extract and sucrose and Stevia product and sucrose was highly significant (P < 0. 000). Conclusion: Stevia leaf extract and commercially available Stevia product did not significantly affect plaque pH values, implying that two solutions are non‑ fermentable and do not support bacterial survival.

Background: Dietary polyphenols, such as those found in green tea and red wine, are linked to antitumor activity. They are known to influence many signaling pathways epigenetically within the human body. In this regard, CPUK02 (15-Oxosteviol benzyl ester) is a new ent-kaurenoid derivative of Stevioside and exhibits strong anti-cancer activityin vitro and in vivo. Nowadays, the role of epigenetics in cancer has been the subject of intensive study and DNA methylation targeting represents a relevant strategy for cancer treatment. There are no reports regarding the effects of CPUK02 on epigenetic alterations in colorectal cancer cell line. This study was an attempt to compare CPUK02 with 5-AZA as DNMT inhibitor agent and evaluate whether it can induce its anti-cancer effects via altering the level of DNMT3b mRNA, MGMT and SFRP2 methylation pattern in HCT 116 cell line.Methods: To evaluate DNMT3b expression, DNMT3B mRNA levels in HCT116 CRC cell line were quantified by real-time reverse-transcriptase Polymerase Chain Reaction (PCR) assay after 24hr of incubation time with CPUK02 and 5-AZA. In addition, the methylation patterns of 2 CpG islands in this cell line were examined by methylationspecific PCR methods.Results: CPUK02 surprisingly, decreased the DNMT3b mRNA level. The average expression levels of DNMT3b in HCT116 treated with CPUK02 and 5-AZA relative to the GAPDH expression level in control were 0.16 and 0.5%, respectively. Furthermore, CPUK02 could decrease the methylated allele of MGMT and SFRP2 genes in HCT 116 after 24hr.Conclusion: In this study, positive correlation was found between mRNA expression of DNMT3b and gene promoter hypermethylation after treatment with CPUK02 and 5-AZA. Our data confirmed that CPUK02 like 5-AZA exhibits demethylating properties.