title: A study of the precursors of the natural antioxidant phenol 3,4-dihydroxyphenylglycol in olive oil waste.
abstract: 3,4-Dihydroxyphenylglycol (DHPG) is a potent antioxidant recently found in the free form in olive oil and table olives. DHPG can be recovered from olive oil solid waste by a hydrothermal treatment. It was observed that an increase in the concentration of DHPG occurred when alperujo aqueous extracts were subjected to mild thermal conditions (post-treatment). This fact indicates that certain solubilized compounds or precursors containing DHPG which is released with the post-treatment. In the present study, the precursors of DHPG were identified and characterized after extraction from alperujo using thermal treatment and purification by fractionation on Amberlite® XAD16 polyamide and semi-preparative reverse-phase HPLC columns. Their structures were elucidated using HPLC coupled to diode array detector (DAD) and electrospray ionization mass spectrometry (ESI-MS). The results identified three compounds as precursors, and their structures can be attributed to the diastereoisomeric forms of the two β-hydroxy derivatives of verbascoside and isoverbascoside (β-hydroxyacteoside and β-hydroxyisoacteoside), and 2″-hydroxyoleuropein, all of which contain a DHPG moiety, potentially explaining the increases in the concentration of this phenolic compound in olive oil waste.
authors.affiliation: Departamento de Biotecnología de Alimentos, Instituto de la Grasa (Consejo Superior de Investigaciones Científicas, CSIC), Avda. Padre García Tejero, 4, 41012 Seville, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Lama-Muñoz
authors.forename: Guillermo
authors.initials: G
authors.lastname: Rodríguez-Gutiérrez
authors.forename: Fátima
authors.initials: F
authors.lastname: Rubio-Senent
authors.forename: Rafael
authors.initials: R
authors.lastname: Palacios-Díaz
authors.forename: Juan
authors.initials: J
authors.lastname: Fernández-Bolaños
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D008734:Methoxyhydroxyphenylglycol / Q000031:analogs & derivatives* / Q000737:chemistry; D015394:Molecular Structure; D000069463:Olive Oil; D010636:Phenols / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry*; D010938:Plant Oils / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D014866:Waste Products / Q000032:analysis*
chemical_list: D000975:Antioxidants; D000069463:Olive Oil; D010636:Phenols; D010936:Plant Extracts; D010938:Plant Oils; D014866:Waste Products; D008734:Methoxyhydroxyphenylglycol; C010117:3,4-dihydroxyphenylglycol