alpha-Glucosidase inhibitory antihyperglycemic activity of substituted chromenone derivatives

Series of 3,4- and 3,6-disubstituted chromenones including new chromenone derivatives were synthesized applying various synthetic strategies including Pechmann condensation, Knoevenagel condensation, Reimer-Tiemann reaction and Suzuki coupling in very good yields. Synthesized compounds (4a-z) were screened for in vitro alpha-glucosidase inhibitory and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activities. Majority of compounds displayed varying degrees of alpha-glucosidase inhibitory and DPPH scavenging activity. Compound 4x emerged as the most potent alpha-glucosidase inhibitor in present series of compounds owing to the presence of 3-acetyl-6-(6-methoxy-3-pyridyl) group on chromenone; however, it could not display DPPH scavenging activity and was found to be mixed noncompetitive type inhibitor of rat intestinal alpha-glucosidase. When tested in vivo for antihyperglycemic activity in starch loaded Wistar rats, it displayed significant antihyperglycemic property. This is the first report assigning rat intestinal alpha-glucosidase inhibitory property for this class of new chromenones and presents new family of compounds possessing alpha-glucosidase inhibitory activities and antihyperglycemic property. Compound 4x may serve as an interesting new compound for the development of therapeutics targeted against diet-induced hyperglycemia in diabetes. (C) 2009 Elsevier Ltd. All rights reserved.