SMAD2 and diabetes mellitus: Zhang et al. [116] found that ginsenoside Rb1 can reduce ROS production, inhibit the expression of NOX subtypes NOX1 and NOX4, and downregulate the expression of NADPH oxidase induced by diabetes mellitus (DM), and the mechanism is related to the inhibition of the TGFβ1/Smad2/3 pathway.