Identification of Tyrosyl Oleate as a Novel Olive Oil Lipophenol with Proliferative and Antioxidant Properties in Human Keratinocytes.

Cinzia Benincasa,Erika Cione,Pierluigi Plastina,Maria Cristina Caroleo,Alessia Fazio,Chiara La Torre,Enzo Perri

doi:10.3390/antiox10071051

Cinzia Benincasa, Erika Cione + Show 5 more

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https://doi.org/10.3390/antiox10071051

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Abstract

Lipophenols are an emerging subclass of phenolic compounds characterized by the presence of a lipid moiety. Recently, hydroxytyrosyl oleate (HtyOle), a derivative of hydroxytyrosol, has been identified in olive oil and by-products. Furthermore, HtyOle possesses anti-inflammatory, antioxidant, and tissue regenerating properties. In this work, the potential occurrence of tyrosyl oleate (TyOle) in olive oil was investigated based on the hypothesis that its precursors tyrosol and oleic acid, both present in relatively high amount can be coupled together. Moreover, TyOle effects have been investigated in human keratinocytes to verify its proliferative and antioxidant properties. The quantitative determination of TyOle was carried out by the external standard method in liquid chromatography coupled with mass spectrometry (LC/MS), in negative mode using multiple reaction monitoring (MRM). The proliferative properties of TyOle on immortalized human keratinocytes (HaCat) were evaluated by 3-(4,5-dimethylthiasol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Morphological changes were observed by fluorescent staining with phalloidin (for F-actin) or 4,6-diamidino-2-phenylindole (DAPI, for chromatin) dye. The antioxidant activity was assessed at the level of production of mitochondrial reactive oxygen species (ROS) induced with UV exposure. TyOle was identified in all the oil samples investigated. Interestingly, TyOle concentration was higher in defective or low-quality oils than in extra virgin oils. The formation of TyOle likely occurs during the crushing and kneading processes and its concentration is related to the increase of rancidity and of the concentration of free precursors. Herein we show that TyOle induced an increase in the viability of HaCat cells and cytoskeletal remodeling.

Highlights

IntroductionThe nutritional value and the health promoting effects of olive oil rely on its favorable nutrient composition, including oleic acid (OA) as the most abundant fatty acid and fat-soluble vitamins and the presence of phenolic compounds [2,3,4,5]
Despite these compounds having been mainly known as semi-synthetic phenolic derivatives characterized by enhanced antioxidant activities, hydroxytyrosyl oleate (HtyOle, Figure 2), a derivative of Hty containing an oleic acid residue, has been recently found in olive oil [13]
tyrosyl oleate (TyOle) was found in higher concentration in defective or low-quality oils than in extra virgin olive oil (EVOO)

Summary

Introduction

The nutritional value and the health promoting effects of olive oil rely on its favorable nutrient composition, including oleic acid (OA) as the most abundant fatty acid and fat-soluble vitamins and the presence of phenolic compounds [2,3,4,5]. The latter are recognized in contributing to the positive health effects related to the consumption of extra virgin olive oil (EVOO) [6,7].

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