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

• Autor(a) principal: Gouveia-Figueira, Sandra C.
• Data de Publicação: 2015
• Outros Autores: Castilho, Paula C.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.13/3216
• topic: Rubus; Berries; Phenolic compounds; HPLC–DAD–ESI/MSn; Antioxidan; .; Faculdade de Ciências Exatas e da Engenharia

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 phe nolic 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 prop erties (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 mol eq Trolox/g DM; ABTS value of 255.8 ± 1.9 mol eq Trolox/g DM and FRAP value 9455 ± 29 mmol Fe(II)/mgDM).