LC-MS guided isolation of phenolic glycosides from Rolfe leaves and their ‑amylase and -glucosidase inhibitory activities.

Rolfe is widely used in China as folk medicine. The bioactivity evaluation indicated that the -BuOH fraction of leaves (VLLB) could significantly inhibit ‑amylase and -glucosidase. In order to clarify its active constituents, the phytochemical analysis on VLLB was first performed using HPLC-QTOF-MS/MS, and three new phenolic compounds, viburosides A-C (-), along with seven known analogues (-) were isolated through preparative HPLC. The undescribed compounds were determined by extensive spectroscopic analyses (H and C NMR, HSQC, HMBC, HRESIMS, and ORD) and enzymatic hydrolysis. In the enzyme assays, compounds - showed potent ‑amylase and -glucosidase inhibitory activities. The enzymatic kinetics and molecular docking of the strongest inhibitors and against the corresponding target enzyme were also performed.