Aldose reductase is a small, cytosolic, monomeric enzyme which belongs to the aldo-keto reductase superfamily. Aldose reductase catalyzes the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH)-dependent reduction of a wide variety of aromatic and aliphatic carbonyl compounds. It is implicated in the development of diabetic and galactosemic complications involving the lens, retina, nerves, and kidney.
Aldose reductase is both the key enzyme of the polyol pathway, whose activation under hyperglycemic conditions leads to the development of chronic diabetic complications, and the crucial promoter of inflammatory and cytotoxic conditions, even under a normoglycemic status. Aldose reductase represents an excellent drug target and a huge effort is being done to disclose novel compounds able to inhibit it.