Globally, colon cancer is increased gradually and known as one of the major causes of cancer death. Stevia, a substitute of sugar, is known to have many components including alpha-tocopherol and anthocyanin etc, as antioxidants. This study's purpose is to investigate whether stevia plant extract can have a protective effect against colon carcinogenesis induced by azoxymethane (AOM) and dextran sodium sulfate (DSS) in mice. Total 30 male ICR mice were divided into 2 groups; AOM/DSS treatment (control group), AOM/DSS + stevia extract (0.5%, in drinking water). After acclimation for 1 week, five weeks old mice received three intraperitoneal AOM (10 mg/kg b.w.) injections weekly for 3 weeks (0–2nd weeks of the experiment) and 2% DSS as drinking water for the next one week. AIN-76A purified rodent diet and 0.5% stevia extract water were supplied to the animals for 6 weeks. The colons of mice were collected and the number of aberrant crypt foci (ACF) and aberrant crypts (ACs) in colonic mucosa were counted after staining with methylene blue. Malondialdehyde (MDA) concentration in feces were determined. The numbers of ACF and ACs were significantly (p<0.01) decreased in stevia-treated group compared with the control group. The MDA concentration in feces was also significantly (p<0.01) decreased in stevia-treated group compared with the control group. In histopathology of colonic epithelium, hyperplasia of colonic epithelium was less observed in steviatreated group. These results indicate that stevia has a protective effect against colon carcinogenesis induced by AOM/DSS in mice and further study needs to illustrate the protective mechanisms.

Introduction
Materials and Methods
    Materials
    Animals and experimental diets
    Experimental design
    Assay of aberrant crypt foci (ACF)
    Thiobarbituric acid reactive substances (TBARS) assay
    Histopathological examination
    Statistical analysis
Results
    Changes in body weight
    TBARS value in feces
    Histopathology
Discussion
References

• Hang min Jo(College of Veterinary Medicine and Research Institute of Veterinary Medicine, Chungbuk National University)
• Eun Young Kim(Korea Food Culture Promotion Association)
• Wang Young Rhee(Globalstevia)
• Jae-Hwang Jeong(Department of Biotechnology and Biomedicine, Chungbuk Province College)
• Sang Yoon Nam(College of Veterinary Medicine and Research Institute of Veterinary Medicine, Chungbuk National University)
• Beom Jun Lee(College of Veterinary Medicine and Research Institute of Veterinary Medicine, Chungbuk National University) Corresponding author