For instance, Salvianolic acid B was shown to attenuate paraquat-induced pulmonary fibrosis by restoring the Nrf2/NOX4 redox balance, where Nrf2 activation suppressed NOX4 expression and downstream TGF-β1/Smad3 signaling (Liu et al., 2016). Here, SMAD3 is linked to pulmonary fibrosis.