Nine new compounds (1-9), including four dihydrochalcone glycosides, two dibenzofuran glycosides, and two biphenyl glycosides, were isolated from the leaves of the medicinal plant Malus hupehensis collected in Shennongjia Forestry District (Hubei, China). Their structures were elucidated by comprehensive spectroscopic techniques, including HRESIMS and NMR spectra. All compounds were tested by preliminary biological evaluation for their α-glucosidase inhibitory and NO production activities. Compound 4 was found to show significant inhibitory activity against NO production in LPS-activated RAW 264.7 macrophage cells with an IC50 value of 29.60 μM, and compounds 3 and 4 were found to exhibit potent α-glucosidase inhibition with IC50 values of 44.17 and 60.15 μM, respectively. This work represents the first report of the diverse glycosides from the plant Malus hupehensis. It expands our understanding of the secondary metabolites of this medicinal plant and lays the foundation for the study of the bioactive principles of the ethnic hypoglycemic medicinal plant.
Keywords: Malus hupehensis (Pamp.) Rehd.; NO production activity; dihydrochalcone glycosides; rosaceae; α-glucosidase inhibitor.