Isolation and characterization of a new hydroxytyrosol derivative from olive (Olea europaea) leaves.
A new secoiridoid compound was isolated from the leaves of Olea europaea. This compound, not previously identified, is the bis methylacetal of oleuropein aglycone, the 3,4-dihydroxyphenylethyl [(2,6-dimethoxy-3-ethylidene)-tetrahydropyran-4-yl]acetate (3,4-DHPEA-DETA), and was found in different olive cultivar phenolic extracts as one of the major secoiridoid components. This compound was shown to be easily transformed in acidic aqueous media into 3,4-DHPEA-EDA, the major polyphenolic compound found in olive oil, and permitted us to increase the yield of 3,4-DHPEA-EDA isolation from the olive leaf extract. The antiradical activity of this new compound, evaluated by scavenging of 2,2-diphenyl-1-picrylhydrazyl radicals, was much higher than the one found for 3,4-DHPEA-EDA or alpha-tocopherol. Results also call to attention the need for a careful identification of compounds by HPLC-MS, usually performed in acidic conditions.
Paiva-Martins
Fátima
F
Centro de Investigacao em Quimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, n degrees 687, 4169-007 Porto, Portugal. mpmartin@fc.up.pt
Pinto
Marisa
M
D000085:Acetates / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification*; D002851:Chromatography, High Pressure Liquid; D016166:Free Radical Scavengers / Q000737:chemistry; D013058:Mass Spectrometry; D031658:Olea / Q000737:chemistry*; D010636:Phenols; D018515:Plant Leaves / Q000737:chemistry*; D011714:Pyrans / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification*
C531025:3,4-dihydroxyphenyl ((2,6-dimethoxy-3-ethylidene)tetrahydropyran-4-yl)acetate; D000085:Acetates; D016166:Free Radical Scavengers; D010636:Phenols; D011714:Pyrans