Nitro-fatty acids formation in Virgin Olive Oil during gastric digestion and its relationship to cultivar and fruit ripening
Virgin olive oil (VOO) represents the main source of unsaturated lipids in the Mediterranean diet associated with low mortality. Health benefits of VOO rely on its composition, mainly fatty acids and minor components such as polyphenols. In addition, VOO contains nitro-fatty acids (NO2-FA), novel signaling mediators exhibiting pleiotropic anti-inflammatory responses. Previous work from our group reported the presence of nitro-oleic acid (NO2-OA), nitro-linoleic acid (NO2-LA) and nitro-conjugated linoleic acid (NO2-cLA) in extra virgin olive oil under gastric conditions. Herein, we analyzed the fatty acid profile, phenol, pigment and NO2-FA formation in two contrasting Uruguayan olive cultivars, Arbequina and Coratina at two ripening conditions. We demonstrate that VOO fatty acid nitration is dependent on olive cultivar as well as fruit ripening. Under gastric nitration conditions, the presence of polyphenols in Arbequina VOO promoted fatty acid nitration. In contrast, the absence of polyphenols favor lipid oxidation, decreasing fatty acid nitration. In Coratina, where the content of polyphenolic compounds is higher than in Arbequina, their absence did not affect the formation of NO2-FA. Coratina contains other bioactive constituents such as pigments that could play an important role in protection of VOO from lipid oxidation. Overall, we postulate that unsaponifiable constituents of VOO, e.g. polyphenols and pigments, contribute to the formation of NO2-FA in gastric conditions, thus potentiating their health beneficial