An oral toxicity test in rats and a genotoxicity study of extracts from the stems of Opuntia ficus-indica var. saboten.

BACKGROUND: Opuntia ficus-indica var. saboten (OFIS) is used widely in Korea to treat constipation due to its diuretic effects and its enhancement of bowel function and appetite. However, its safety has not yet been established. The aim of this study was to evaluate the repeated oral toxicity and genotoxicity of OFIS extract (OE).

METHODS: White female and male Sprague Dawley rats (n = 6) were divided into 4 groups, and OE was administered to them orally (0, 500, 1000, and 2000 mg/kg/day, respectively) for one week. The Ames test, the chromosomal aberration assay, and the mammalian micronucleus test were performed to determine the OE genotoxicity. The Ames test was conducted using Salmonella typhimurium (S. typhimurium) strains TA100, TA1535, TA98, and TA153 and Escherichia coli (E. coli) WP2 urvA, and Chinese hamster lung (CHL) cells were used for the chromosomal aberration assay. The mammalian micronucleus test was performed using mouse bone marrow cells.

RESULTS: This study revealed that OE administration did not alter the normal rat behavior, body weight gain, and food and water consumption with respect to the normal controls. In addition, there were no toxic effects observed during the ophthalmological test. The biochemical hematological and serum values as well as urinalysis parameters and organ weights were all similar to those of the normal control group. In addition, no mutagenicity effects from the OE were found in S. typhimurium or E. coli with or without S9 activation according to the Ames test. The OE did not significantly alter the number of structural aberrations in the CHL cells in the presence or absence of S9 activation. The oral administration of OE also caused no significant increase in the number of micronucleated polychromatic erythrocytes or in the mean ratio of polychromatic to total erythrocytes.

CONCLUSIONS: In conclusion, OE could be considered as a reliable and safe herbal medicine or functional food since no toxicity was found under the conditions of this study.