Chalcones and their pyrazine analogs: synthesis, inhibition of aldose reductase, antioxidant activity, and molecular docking study

Abstract

Chalcones and their pyrazine analogs synthesized by Claisen–Schmidt condensation were tested for inhibition of aldose reductase, which is the key enzyme in the development of secondary diabetic complications. The most active compounds exerted IC50 values within the micromolar scale, and their interactions with the enzyme were described in a molecular docking study. Antioxidant activity of several representative compounds was explored in DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, revealing significant scavenging for 4-hydroxy-substituted derivatives endowed with electron-donating methoxy substituent in position 3 of the ring B. To conclude, the novel chalcones hydroxylated and methoxylated in the B-ring and their pyrazine analogs exhibited significant aldose reductase inhibition activity, albeit lower in comparison with the reference epalrestat. Medium antioxidant activity (not exceeding the antioxidant efficacy of the standard Trolox) was shown by the representative compounds tested.