The occurrence in olive oil of a new class of phenolic compounds: hydroxy-isochromans

A new class of phenolic compounds, hydroxy-isochromans, was found in different samples of extra-virgin olive oil. In particular, the presence of l-phenyl-6,7-dihydroxy-isochroman, 10 and 1-(3′-methoxy-4′-hydroxy)phenyl-6,7-dihydroxy-isochroman, 11 was demonstrated by comparison of the high performance liquid chromatography–mass/mass (HPLC–MS/MS) spectra of biophenolic samples from extra-virgin olive oils with those of compounds obtained by a reaction between hydroxytyrosol and the aromatic aldehydes, benzaldehyde and vanillin, respectively.