N–O reduced metabolites (Cy1, Cy2, Cy10) had no genotoxicity in three mutation tests.
The maximum tolerated dose (MTD) of metabolites was above 6000 mg/kg b.w./day.
The high-dose groups of Cy1 and Cy-M showed pathological changes in the liver.
The NOAEL for subchronic study of the metabolites was 150 mg/kg diet for rats.