Study of reactive metabolites of food additives and contaminant (bisphenol-A) using dansyl glutathione, and the correlation with their hepatotoxicity

OF THE DISSERTATION Study of Reactive Metabolites of Food Additives and Contaminant (Bisphenol-A) Using Dansyl Glutathione and the Correlation with Their Hepatotoxicity By Thitiwan Buranachokpaisan Dissertation Director: Dr. Paul E. Thomas Biologically reactive metabolites are known for their ability to bind to nucleophilic macromolecules (DNA, proteins, lipids) and their irreversible binding to hepatic proteins is known to lead to necrosis and liver damage. Dansyl glutathione (dGSH), a fluorescent surrogate of glutathione, was used to trap reactive metabolites formed during oxidative metabolism of food additives by rat liver microsomes. dGSH was not commercially available and had to be synthesized. Synthesis of dGSH was improved to achieve a higher yield by reaction in borate buffer. The method, using fluorescent-high performance liquid chromatography for detection/quantitation and mass spectrophotometer for identification, yielded dGSH adducts that are consistent with other studies. dGSH was also found to be a substrate of microsomal glutathione S-transferase enzymes. To correlate the extent of adduct formation with their toxicity, selected hepatotoxic food additives were studies at low (0.1 mM) and high (1 mM)