Exploring the Isomeric Precursors of Olive Oil Major Secoiridoids: An Insight into Olive Leaves and Drupes by Liquid-Chromatography and Fourier-Transform Tandem Mass Spectrometry

Foods

Cosima Damiana Calvano¹  Ilario Losito²  Ramona Abbattista²  Tommaso R. I. Cataldi² 

[1] Centro Interdipartimentale SMART, Università degli Studi di Bari “Aldo Moro”, Via E. Orabona 4, 70125 Bari, Italy;Dipartimento di Chimica, Università degli Studi di Bari “Aldo Moro”, Via E. Orabona 4, 70125 Bari, Italy;

关键词: extra-virgin olive oil;    olive leaves and drupes;    secoiridoids;    oleuropein;    oleuroside;    ligstroside;   

DOI  :  10.3390/foods10092050

来源: DOAJ

【 摘 要 】

Secoiridoids play a key role in determining health benefits related to a regular consumption of extra-virgin olive oil (EVOO), in which they are generated from precursors of the same class naturally occurring in drupes and leaves of the olive (Olea europaea L.) plant. Here, reversed-phase liquid chromatography coupled to electrospray ionization and Fourier-transform single/tandem mass spectrometry (RPLC-ESI-FTMS and MS/MS) was employed for a structural elucidation of those precursors. The presence of three isoforms in both matrices was assessed for oleuropein ([M-H]⁻ ion with m/z 539.1770) and was emphasized, for the first time, also for ligstroside (m/z 523.1821) and for the demethylated counterparts of the two compounds (m/z 525.1614 and 509.1665, respectively). However, only the prevailing isoform included an exocyclic double bond between carbon atoms C⁸ and C⁹, typical of oleuropein and ligstroside; the remaining, less abundant, isoforms included a C=C bond between C⁸ and C¹⁰. The same structural difference was also observed between secoiridoids named elenolic acid glucoside and secoxyloganin (m/z 403.1246). This study strengthens the hypothesis that secoiridoids including a C⁸=C¹⁰ bond, recently recognized as relevant species in EVOO extracts, arise mainly from specific enzymatic/chemical transformations occurring on major oleuropein/ligstroside-like precursors during EVOO production, rather than from precursors having that structural feature.

【 授权许可】

Unknown