Nine new neolignan glycosides (1-9), viburfordosides A-I, two new neolignans, fordianes A and B (10, 11), and seven known analogues (12-18) have been isolated and identified from the fruits of Viburnum fordiae Hance. The structures and absolute configurations of undescribed neolignan constituents were identified by chemical methods and spectroscopic analyses. The α-glucosidase inhibitory, ABTS•+ and DPPH• scavenging, and anti-inflammatory activities of these secondary metabolites were evaluated. Some of them exhibited significant potency in inhibiting α-glucosidase and scavenging free radicals. Among the 14 metabolites that were found to have the capacity to inhibit NO production in LPS-stimulated RAW264.7 macrophage cells, compounds 2, 4, 6, 10, 11, 14, 17, and 18 were potent with IC50 values of 10.88-41.10 μM. These results support that V. fordiae fruits possessing the neolignan compounds may serve as both a functional food and a medicinal resource to prevent and treat type 2 diabetes (T2D).
Keywords: Adoxaceae; Viburnum fordiae Hance; anti-inflammatory; berry fruits; neolignans; radical scavenging; α-glucosidase inhibition.