Bio-affinity ultra-filtration combined with HPLC-ESI-qTOF-MS/MS for screening potential α-glucosidase inhibitors from Cerasus humilis (Bge.) Sok. leaf-tea and in silico analysis

Cerasus humilis   (Bge.) Sok. leaf-tea (CLT) has a potential anti- α -glucosidase effect. However, its anti- α -glucosidase functional compositions remain unclear. Results showed that 70% methanol extract of CLT (IC 50  = 36.57 μg/mL) with the highest total phenolic/flavonoid contents exhibited significantly higher α -glucosidase inhibitory activity ( α -GIA) than acarbose (IC 50  = 189.57 μg/mL). Additionally, phenolic constituents of the CLT extract were analyzed for the first time in this work. Ten major potential α -glucosidase inhibitors ( α -GIs) with high bio-affinity degree in the CLT extract were recognized using a bio-affinity ultra-filtration and HPLC-ESI-qTOF-MS/MS method. In vitro α -GIA assay confirmed that myricetin (IC 50  = 36.17 μg/mL), avicularin (IC 50  = 69.84 μg/mL), quercitrin , isoquercitrin, prunin and guajavarin were responsible for the α -GIA of the CLT extract. More importantly, the interaction mechanism between α -GIs and α -glucosidase was investigated via in silico analysis. This study provides a high-throughput screening platform for identification of the potential α -GIs from natural products.