Discovery of Inhibitory Active Ingredients for α-Amylase and α-Glucosidase from Raspberry (Rubus idaeus L.) Stems and Leaves Guided by Affinity Ultrafiltration and UPLC-QTOF-MS/MS

Raspberry (Rubus idaeus L.) fruits have been widely used due to their abundance of diverse polyphenolic compounds, whereas research on the chemical composition and bioactivity of their stems and leaves remains limited. In this study, the ethyl acetate extract of raspberry stems and leaves was evaluated for inhibitory activity against α-glucosidase and α-amylase. Guided by affinity ultrafiltration–mass spectrometry, 16 potential active components were further isolated and characterized. Among these, 13 compounds exhibited binding affinity for α-amylase, while 5 compounds showed binding affinity for α-glucosidase. Quercetin-3-O-β-D-glucoside-7-O-β-D-gentiobioside was isolated from raspberry stems and leaves for the first time. Procyanidin C3 and quercetin exhibited significant inhibitory effects on the two enzymes. Molecular docking studies hinted at the interactions between these compounds and the key active sites of the two enzymes. These findings suggest that phenolic compounds in raspberry stems and leaves may possess potential as α-glucosidase and α-amylase inhibitors, providing a scientific basis for further research on their application as functional components for blood glucose control.