The aldose reductase inhibitory capacity of Sorbus domestica fruit extracts depends on their phenolic content and may be useful for the control of diabetic complications.

Aldose reductase (ALR2) is a rate-limiting enzyme in the polyol pathway associated with the conversion of glucose to sorbitol and whose activity is implicated in the development of the long-term diabetic complications. Upon previous years, several scientific efforts were focused towards the development of ALR2 inhibitors as effective secondary anti-diabetic drugs. To this regard and during our extensive phytochemical analysis of Sorbus domestica (fam. Rosaceae), twenty nine different extracts, fractions and residues of five different maturity stages of Sorbus domestica fruits were evaluated for their in vitro ALR2 inhibitory capacity. The data obtained thus far have indicated that the diethyl ether and ethyl acetate fractions possess high aldose reductase inhibitory activity. Furthermore, detailed phytochemical LC-DAD-MS (ESI+) analysis of such extracts has shown that this aldose reductase inhibitory activity could be attributed to the high content of flavonoids and hydroxycinnamoyl esters. These results suggest that Sorbus domestica fruit consumption may be a promising way for lowering the incidence of long-term complications of diabetes mellitus, especially at early stages, a possibility being discussed in this paper.