Antidiabetic properties of dietary phenolic compounds: Inhibition effects on alpha-amylase, aldose reductase, and alpha-glycosidase

Aldose reductase (AR), alpha-amylase, and alpha-glycosidase are vital enzymes to prevent diabetic complications. Here, AR was purified from sheep kidney using elementary methods with 111.11-purification fold and with 0.85% purification yield. The interactions between some phenolic compounds and the AR, alpha-glycosidase, and alpha-amylase enzyme were determined. It was found that phenolic compounds exhibit potential inhibitor properties for these enzymes. For alpha-amylase, studied phenolic compounds showed IC50 values in the range of 601.56-2,067.78 nM. For alpha-glycosidase, K-i values were found in the range of 169.25 +/- 27.22-572.88 +/- 106.76 nM. For AR, K-i values in the range of 8.48 +/- 0.56-43.26 +/- 7.63 mu M. However, genistein showed the best inhibition effect toward AR and alpha-glycosidase, but delphinidin chloride exhibited the best inhibition effect against alpha-amylase enzyme. We determined that all compounds showed noncompetitive inhibition effect against AR and alpha-glycosidase. Also, studied phenolic compounds may be useful in the prevention or treatment of diabetic complications.