AKR1B1 and retinal disorder: Due to the key role of ALR2 in the glucose metabolism of persons with DM, in which ALR2 participates in converting the excess of glucose into sorbitol, particularly in insulin-independent tissues such as nerve, lens, retina, and kidney, the compound 1,3,5,8-tetrahydroxyxanthone appears to be a candidate as a therapeutic agent not only in the control of DM but also in the complications associated with DM, such as neuropathies, nephropathies, and retinopathies [101].