Oleacin and oleocanthal: Two olive oil bioactives in multiple chemical forms

Oleacin and oleocanthal are major secoiridoid derivatives of virgin olive oil. Although promising therapeutic agents, e.g. oleocanthal possess anti-inflammatory activities similar to ibuprofen [1], their analysis, detection and quantification in olive extracts and in biological fluids are still complicated. Indeed, their dialdehydic nature makes them extremely unstable, mainly due to their ability to form hemiacetals and to the keto-enolic tautomeric equilibrium that involves also ring-closing. Finally, in a single analysis there is always the question of which chemical form, bioactive compound or artefact, is really detected. To this aspect, this work involves (i) the determination of the basic derivatives of both molecules in protic and aprotic environment employing a hybrid ESI-(+/-)-LTQ-Orbitrap apparatus; (ii) the establishment of the best platform for the analysis and quantification using different stationary phases (e.g. C18, Normal Phase, Hilic, Chiral); (iii) the elucidation of their fragmentation mechanisms by HRMS/MS and (iv) the investigation of their reactivity with key biological agents such as amino acids and nucleosides. The overall will further contribute to the better conception of their chemical nature concerning biosynthesis and will result to new insides related to their pharmacological role. [1] Nature, 437 (2005), 45–46.