TXN and primary biliary cholangitis: The 3 and 7 phenolic hydroxyls endow ursodeoxycholic acid with antioxidant activity; this compound also enhances Nrf2 activation in hepatocytes of PBC patients and increases thioredoxin (TRX) and thioredoxin reductase 1 (TrxR1) proteins, thereby relieving PBC [181].