α-Glucosidase inhibitory activities of constituents from leaves.

is a plant of the Myrtaceae with various pharmacological activity. In this study, the water extract and the isolated compounds from guava leaves were evaluated for α-glucosidase inhibition using spectrophotometric method. Ellagic acid, quercetin, quercetin-3-O-glucuronide, avicularin, isoquercitrin, and quercetin-3-galactoside showed α-glucosidase inhibitory activity, and their IC value were 25.0, 41.0, 53.5, 46.9, 60.0 and 72.1 μg/mL, respectively compared with the positive control acarbose (IC 49.2 μg/mL). This study could provide a theoretical basis for the application of in the treatment of hyperglycemia.