abstract
Phenolic composition, antioxidant and breast cancer antiproliferative activities of water and methanol/water derived extracts from olive pomace (OP) and dry olive mill residue (DOR), from Portuguese industries, were studied. DOR water (DORW) extracts showed the highest extraction yield; as well as the highest total phenolic content (TPC) and hydroxytyrosol (HT) (similar to 25 mg/g extract). HPLC-ESI-MS analysis identified HT in both OP and DOR, whereas HT-1-glucoside, tyrosol, oleuropein aglycone isomers, verbascoside and oleuropein were only detected in DOR. Additionally, a de(carboxymethyl)oleuropein aglycone isomer, in aldehyde form, was reported for the first time in DOR. DOR water extract also presented the most effective DPPH scavenging capacity and antiproliferative activity, comparatively to OP water (OPW) extract. Moreover, antioxidant potential of phenolic compounds present in DORW extract was comparable to HT, and to butylated hydroxyanisole (BHA), a widely used food industry antioxidant. Phenolic compounds present in DORW extract also showed comparable tumor antiproliferative activity on MDA-MB-231, relatively to HT and 5-fluorouracil (5-FU), a well-known cytostatic agent. MDA-MB-231 cell growth inhibition, upon 5-FU incubation was even incremented in the presence of DORW extract. These results demonstrate DOR extracts potential as source of phenolic compounds for nutraceutical applications, as food supplements, opening new strategies for its olive mill residues valorization. (C) 2013 Elsevier B.V. All rights reserved.
keywords
PHENOLIC-COMPOUNDS; LIQUID-CHROMATOGRAPHY; MASS-SPECTROMETRY; OLEA-EUROPAEA; WASTE; COMPONENTS; CULTIVAR; ALPERUJO; POMACE; PULP
subject category
Agriculture
authors
Ramos, P; Santos, SAO; Guerra, AR; Guerreiro, O; Felicio, L; Jeronimo, E; Silvestre, AJD; Neto, CP; Duarte, M
our authors
Ângela Guerra
PhD Student
Armando Jorge Domingues Silvestre
Full professor
Carlos Pascoal Neto
Raiz Director
Maria de Fátima Pereira Duarte
Principal Researcher
Patrícia Alexandra Bogango Ramos Portela
Post-Doc Fellowship
Sónia Andreia Oliveira Santos
Assistant Researcheracknowledgements
The authors want to thank COMPETE (Competitivity Factors Operation Program), QREN (National Strategy Reference, Portugal, 2007-2013), ADI (Agency of Innovation) and Regional Development European Foundation for their financial support to RefinOlea Project (FCOMP-01-0202-FEDER-005450), the Associate Lab CICECO funding (Pest-C/CTM/LA0011/2011) and Mariano Lopes & Filhos, Lda. for kindly supply olive oil by-products.