Aldose reductase inhibitors in the functional foods: Regulation of diabetic complications

Abstract

Aldose reductase (AR) is implicated in the precipitation of diabetic complications including the microangiopathy such as nephropathy, neuropathy, retinopathy as well as macroangiopathy such as cardiovascular disease in diabetes patients. A number of synthetic inhibitors of AR have been tested in laboratories as well as in the clinical settings but with limited success due to their low bioavailability and safety concerns. Since the epidemiological studies suggest the enormous increase in incidence of diabetes globally, there is urgent need for potent yet safe AR inhibitors. The molecules derived from plants usually show greater biocompatibility and lack toxicity and other harmful side effects due to their coevolution with human and also because they have been the part of the local diet regimen for the millennia. Several researchers have reported that crude extracts as well as pure molecules derived from natural sources such as plants and various plant parts possess excellent AR inhibitory activity. Such compounds have shown remarkable inhibition of elevated AR activity during diabetic condition. Although the chemical nature of the plant extracts is of mixed type, the pure molecules isolated from plants are of varied chemical nature such as flavonoids, alkaloids, phenolics, tannins, coumarins, terpenoids, etc. In this chapter the different plant-derived extracts and compounds have been discussed that have been shown to have potential AR inhibition activity and may qualify to be considered as the functional food for prevention of diabetes and diabetic complications.