Screening inhibitory effects of selected flavonoids on human recombinant aldose reductase enzyme: in vitro and in silico study

Aldose reductase (AR) is the first enzyme of the polyol pathway that has physiological importance under hyperglycaemic conditions. The article has been focussed on AR enzyme inhibition by selected compounds. For this purpose, the in vitro inhibitory effects of various compounds on commercially available recombinant human AR (rAR) enzyme activity were investigated. The IC₅₀ values of compounds on rAR inhibition effect were found for 6-hydroxy flavone, syringic acid, diosmetin, 6-fluoroflavone, 7-hydroxy-4'-nitroisoflavone, myricetin as 2.05, 2.97, 15.75, 16.1, 49.5, and 63 µM, respectively. 6-Hydroxy flavone and syringic acid competitively inhibited rAR with respect to the NADPH with K_i values 0.509 ± 0.036 and 0.842 ± 0.012 µM. In addition, docking studies were performed to evaluate the potential enzyme binding positions of the compounds. Our in vitro and in silico results indicated that the 6-hydroxy flavone may be a good lead compound in the development of AR inhibitors to prevent diabetic complications.