Phytotransformation and Metabolic Pathways of 14C-Carbamazepine in Carrot and Celery.

Carbamazepine (CBZ) is an anticonvulsant pharmaceutical compound of environmental concern due to its persistence, bioactive toxicity, and teratogenic effects. Studies on the kinetics and metabolic pathways of CBZ in plant tissues are still limited. In the present study, the phytotransformation of 14C-CBZ was explored. The 14C detected in bound residues was lower than in extractable residues (>85% of the uptaken 14C radioactivity) in plant tissues. CBZ underwent appreciable transformation in plants. A large portion of accumulated 14C radioactivity (80.3 ± 6.4%) in the cells was distributed in the cell water-soluble fraction. A total of nine radioactive transformation products of CBZ were identified, three of which were generated in vivo due to the contraction of the heterocycle ring. The proposed metabolic pathways revealed that conjugation with glutathione or phenylacetic acid was the major transformation pathway of CBZ in plants, with the contribution of epoxidation, hydroxylation, methoxylation, methylation, amination, and sulfonation.