Stabilized rice bran extract: Acute and 28-day repeated dose oral toxicity with in vitro mutagenicity and genotoxicity study

The toxicity of Egyptian stabilized rice bran extract (RBE) has been evaluated for acute and repeated 28 day oral toxicity with the outcome of genotoxicity. The extract was administered to female white albino rats at 2000 mg kg-1 for acute testing and to male and female rats at concentrations of 1000, 500, and 100 mg kg-1 for 28 days. Mutagenic potential was evaluated. Chromosomal and DNA damage using standard karyotyping and alkaline comet assay were applied. Acute study showed neither deaths nor gross of pathological abnormalities. In 28 days study, no dose-related changes were observed in body weights, haematological as well as the majority of the serum biochemistry parameters. Results showed neither mutagenic nor genotoxic effects of the RBE. Histological findings showed significant changes in rat groups administering 1000 and 500 mg kg-1 doses. The extract proved to be non toxic acutely and the degree of toxicity was noticed to be dose dependent after chronic administration. Thus we suggest that RBE at dose of 100 mg kg-1 (equivalent to 1 g oil daily consumption) is safe to be administered as dietary supplement for long term use. Key words: Stabilized rice bran oil extract (RBE), ames test, alkaline comet assay, chromosomal aberrations, white albino rats.