A new method for screening aldose reductase inhibitors using ultrahigh performance liquid chromatography-tandem mass spectrometry

In this study, an ultrahigh performance liquid chromatography and tandem mass spectrometry (UPLC-MS/MS) method was developed for the detection of aldose reductase (AR) activity and the screening of AR inhibitors in vitro. Glucose was chosen as the substrate of the enzymatic reaction system according to the polyol pathway. In the polyol pathway, glucose could be converted into sorbitol. The multiple reaction monitoring (MRM) mode was used to directly detect the level of sorbitol from each analyte and the amount of sorbitol could be reduced via the addition of an inhibitor. The proposed approach had been successfully applied to determine the AR inhibitory activities of epalrestat, flavonoids and natural product extracts. Additionally, we proposed a detailed discussion of the structure-activity relationships of flavonoids according to the inhibitory activities of thirty-two flavonoids. The screening method proposed in our study was similar to the metabolic pathway in diabetic patients and could eliminate the interference of other substances. We could envision that our method could be used for the screening of AR inhibitors as drugs for the treatment of related diabetic complications.