LC–MS guided isolation of phenolic glycosides from Viburnum luzonicum Rolfe leaves and their α‑amylase and α-glucosidase inhibitory activities

Abstract

Viburnum luzonicum Rolfe is widely used in China as folk medicine. The bioactivity evaluation indicated that the n-BuOH fraction of V. luzonicum leaves (VLLB) could significantly inhibit α‑amylase and α-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 (1–3), along with seven known analogues (4–10) were isolated through preparative HPLC. The undescribed compounds were determined by extensive spectroscopic analyses (¹H and ¹³C NMR, HSQC, HMBC, HRESIMS, and ORD) and enzymatic hydrolysis. In the in vitro enzyme assays, compounds 1–8 showed potent α‑amylase and α-glucosidase inhibitory activities. The enzymatic kinetics and molecular docking of the strongest inhibitors 2 and 3 against the corresponding target enzyme were also performed.

Graphical Abstract

Keywords:

• Viburnum luzonicum Rolfe leaves
• LC-MS analysis
• chemical constituents
• α‑amylase inhibition
• α-glucosidase inhibition

Acknowledgements

We are grateful to the Analytical Detective Center in Yangzhou University for recording spectroscopic spectra.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

NMR, MS and IR spectra, as well as LC-MS and bioactivity-related data were available in Figures S1−S23 and Tables S1−S4, respectively.

Additional information

Funding

This work was supported by the Open Foundation of Green Pesticides and Biotechnology Key Laboratory of Guizhou University of Ministry of Education (2021GDGP0103/2021GDGP0104).