Phenolics from strawberry cv. Falandi and their antioxidant and α-glucosidase inhibitory activities

Three new phenolic glucosides, falandiosides A (1), B (2), and C (6) were isolated from strawberry (Fragaria × ananassa Duch.) cv. Falandi fruit, together with three flavone glucuronides (3-5), eleven lignan glycosides (12-22), and five others. Their structures were determined by spectroscopic methods. All the known phenolics were reported from strawberry for the first time. They were evaluated for antioxidant and α-glucosidase inhibitory activities. Three new and fifteen known phenolics showed potent 2,2′-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical cation scavenging activity with IC50 values of 22.50-4.28 μM in comparison to l-ascorbic acid (14.21 μM). Quercetin 3-(6-methylglucuronide) (4), (+)-isolariciresinol 9′-glucoside (12), and (−)-isolariciresinol 9′-glucoside (13) were active in scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. Moreover, compounds 12 and 13 had moderate ferric reducing antioxidant power (FRAP) values. Further, two new and seven known phenolics exhibited more potent α-glucosidase inhibitory activity with IC50 values of 537.43-25.39 μM than acarbose (619.94 μM).