Phenolic screening by HPLC–DAD–ESI/MSn and antioxidant capacity of leaves, flowers and berries of Rubus grandifolius Lowe

•Characterization of phenolic compounds from Rubus grandifolius Lowe berries, leaves and flowers by HPLC–DAD–ESI/MSn.•Characterization of flavonol O-glycosilated, quinic acid and caffeic acid conjugates.•Anthocyanins were identified using HPLC–DAD–ESI/MSn in positive mode.•Berries have a higher radical scavenger capacity and reducing properties than the leaves.

In Madeira Island (Macaronesia Island), Rubus grandifolius Lowe berries, locally known by amoras, are widely consumed fresh or processed as jam, juice or liquor. Folk medicine describes R. grandifolius Lowe fruits and leaves being used to treat diabetes, as depurative, diuretic and to relieve sore throat.The aim of this study was to investigate phenolic composition and antioxidant capacity of the different edible parts of the plant (berries, leaves and flowers). HPLC–DAD–ESI/MSn was used to establish the phenolic profile. Phenolic monomers such as flavonol O-glycosilated (quercetin and kaempferol), quinic acid and caffeic acid conjugates were characterized using the electrospray source in the negative mode; while positive mode was employed to detect glycosylated anthocyanins (cyanidin, delphinin and petunidin).The berries presented a higher radical scavenger capacity (DPPH and ABTS assays) and reducing properties (FRAP) than the leaves and the flowers. Ethanolic extracts showed highest antioxidant capacity when compared with water based extracts: DPPH values of 147.9 ± 0.7 μmol eq Trolox/g DM; ABTS value of 255.8 ± 1.9 μmol eq Trolox/g DM and FRAP value 9455 ± 29 mmol Fe(II)/mgDM).

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