Bio-Elimination of Conjugated Metabolites of 3-Bromobenzanthrone in Urine of Rats and Guinea Pigs

The profile of urinary metabolites of 3-bromobenzanthrone (3-BBA), an extensively used anthraquinone dye intermediate, in rats and guinea pigs was investigated using HPTLC system. A total of 10 fluorescent metabolites were detected in the urine of guinea pigs as compared to 8 in rats including the parent compound 3-BBA. The elimination of metabolites increased in a dose dependent manner in rats. The Rf values of metabolites in rats were 0.14, 0.29, 0.42, 0.52, 0.58, 0.64, 0.77 and 0.91 while that in guinea pigs were 0.23, 0.26, 0.34, 0.37, 0.44, 0.54, 0.56, 0.68, 0.76 and 0.95. The urine of 3-BBA (50 mg/kg b.wt) treated guinea pigs when digested with acid showed the disappearance of metabolite 1, 2, 5 and 7 indicating these to be the conjugated metabolites. Further, digestion of urine of 3-BBA treated guinea pigs with glucuronidase showed disappearance of metabolite 5 and 7 suggesting these as glucuronide conjugates. Digestion of urine with sulfatase enzyme resulted in disappearance of metabolite 1 which could be a sulfate conjugate. Urinary metabolite 2 which was found to be present even after digestion with glucuronidase or sulfatase but disappeared following acid treatment appears to be glutathione conjugate(s) which resulted in formation of metabolite 3 and 6. These results suggest that conjugated fluorescent metabolites of 3-BBA are excreted in urine of rats and guinea pigs.