Deglycosylation of Two Typical Plant-Generated Glycoconjugates of Tetrabromobisphenol A Through in Vitro Digestion Processes

Tetrabromobisphenol A (TBBPA) is extensively detected in various environmental media. Its typical glycosylation products in plants, TBBPA mono-beta- D-glucopyranoside (TBBPA MG) and TBBPA di-beta-D-glucopyranoside (TBBPA DG), are likely to enter the human body through the oral route. The deglycosylation processes of TBBPA MG and TBBPA DG in both simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) were studied. Results showed that 68% of TBBPA MG was transformed to TBBPA after 6 h incubation in gastrointestinal fluid, about 31% and 7% of TBBPA DG were transformed to TBBPA MG and TBBPA, respectively. In SGF, strong acid hydrolysis mainly contributed to the deglycosylation of TBBPA MG and TBBPA DG. In SIF, the bacteria, the synergistic effect of bacteria and pancreatin, and the bile led to the deglycosylation of TBBPA MG and TBBPA DG. The results indicated glycosylation products of TBBPA formed in vegetables or crops will be partially transformed into TBBPA and partially retained in the forms of glycosylation products in the human digestion system and may enter into the circulation system. These TBBPA glycoconjugates and the released TBBPA will cause health risks. This finding improved our understanding on the environmental fates, exposures, and health risks of TBBPA and its important phytometabolites.