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 x 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 alpha-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 mu M in comparison to L-ascorbic acid (14.21 mu M). 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 alpha-glucosidase inhibitory activity with IC50 values of 537.43-25.39 mu M than acarbose (619.94 mu M). (C) 2015 Elsevier Ltd. All rights reserved.