Deglycosylation Enhances the Toxicity of Plant-Derived Glycosyl Bisphenol A during Gastrointestinal Digestion

Bisphenol A (BPA) is one of the most used plasticizers and a known endocrine disrupting chemical. In plants, BPA is easily conjugated to form conjugates such as glycosyl BPA, and humans can be exposed to such conjugates when ingesting BPA-contaminated plant foods. This study considered the potential of deconjugation of glycosyl BPA in a simulated human gastrointestinal tract system and evaluated the subsequent changes in biological activity using the Caco-2 colon cell model. Glycosyl BPA was found in both soil and lettuce with concentrations ranging from not detected (ND) to 82.51 ng/g dry weight in edible plant tissues, and the level of glycosyl BPA was correlated significantly with that of BPA. Gastrointestinal digestion triggered progressive deglycosylation of glycosyl BPA with the deconjugation rate significantly higher in the intestinal phase (41.7-47.8%) than the gastric phase (13.4-23.3%). Deglycosylation of glycosyl BPA was associated with decreased Caco-2 cell activity and increased markers of oxidative stress and inflammatory responses in the cell. The re-released BPA may be key to the increased toxic effects. These findings highlight the underestimated health risks posed by plant-derived conjugated xenobiotics through transformation reactivation in the human digestive system.