Antioxidant and Anti-atherogenic Activities of Olive Oil Phenolics

Abstract

The aim of the current study was to investigate the antioxidant and cellular activity of the olive oil phenolics oleuropein, tyrosol, hydroxytyrosol, and homovanillic alcohol (which is also a major metabolite of hydroxytyrosol). Well-characterized chemical and biochemical assays were used to assess the antioxidant potential of the compounds. Further experiments investigated their influence in cell culture on cytotoxic effects of hydrogen peroxide and oxidized low-density lipoprotein (LDL), nitric oxide production by activated macrophages, and secretion of chemoattractant and cell adhesion molecules by the endothelium. Inhibitory influences on in vitro platelet aggregation were also measured. The antioxidant assays indicated that homovanillic alcohol was a significantly more potent antioxidant than the other phenolics, both in chemical assays and in prolonging the lag phase of LDL oxidation. Cell culture experiments suggested that the olive oil phenolics induce a significant reduction in the secretion of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 (and a trend towards a reduced secretion of monocyte chemoattractant protein-1), and protect against cytotoxic effects of hydrogen peroxide and oxidized LDL. However, no influence on nitric oxide production or platelet aggregation was evident. The data show that olive oil phenolics have biochemical and cellular actions, which, if also apparent in vivo, could exert cardioprotective effects.

Antioxidant Activities of Hydroxytyrosol Main Metabolites Do Not Contribute to Beneficial Health Effects after Olive Oil Ingestion

“…Both HOTYR and HVAlc expressed much stronger protective effects than Trolox against LDL oxidation by extending the lag time of dienes formation to almost twice the concentration of 1 M (Fig. 2A), which was in agreement with previously reported data (Turner et al, 2005;Rietjens et al, 2007). In contrast, TYR appeared to have very weak activity in this model even at the highest concentration (10 M) ( Fig.…”

Biological Properties of Hydroxytyrosol and Its Derivatives

“…Oxidation of low-density lipoproteins (LDLs) is a lipid peroxidation chain reaction, which is initiated by free radicals. It has been shown that hydroxytyrosol can inhibit LDL oxidation efficiently due to its capacity to scavenge peroxyl radicals (Arouma et al, 1998;Turner et al, 2005). Hydroxytyrosol reduces oxidation of the low-density lipoproteins carrying cholesterol (LDL-C), which is a critical step in the development of atherosclerosis and other cardiovascular diseases (Gonzalez-Santiago et al, 2010;Vázquez-Velasco et al, 2011); hydroxytyrosol has also a potential protective effect against oxidative stress induced by tertbutyl hydroperoxide (Goya et al, 2007).…”

The Plant Natural Products: Their Antioxidants, Free Radical Scavengers, DNA Protection and Antimicrobial Activities

“…Furthermore, The extracts from Geranium sanguineum L and Acacia species plants were also rich with polyphenol compounds and were found to exhibit a strong antioxidant, anti-mutagenic and radical scavenging capacities [43][44][45]. The antioxidant activities for each the Moldavian balm (Dracocephalum moldavica L), olive oil and A. chamaepitys essential oil were found to be as result of its contents of flavonoids and can be used in medicine and pharmacology for treatment of several diseases [46][47][48].…”