Differences in the Neuroprotective Effect of Orally Administered Virgin Olive Oil (Olea europaea) Polyphenols Tyrosol and Hydroxytyrosol in Rats

• Published in: Journal of agricultural and food chemistry Vol. 63; no. 25; pp. 5957 - 5963
• Main Authors: De La Cruz, José Pedro, Ruiz-Moreno, Maria Isabel, Guerrero, Ana, Reyes, José Julio, Benitez-Guerrero, Adela, Espartero, José Luis, González-Correa, José Antonio
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 01-07-2015; American Chemical Society, Books and Journals Division
• Subjects: Animals; antioxidant activity; antioxidants; Antioxidants - metabolism; brain; correlation; ethyl ether; interleukin-1beta; Lipid Peroxidation; Male; Neuroprotective Agents - metabolism; neuroprotective effect; Olea - metabolism; Olea europaea; Olive Oil - metabolism; oral administration; Oxidative Stress; Phenylethyl Alcohol - analogs & derivatives; Phenylethyl Alcohol - metabolism; Plant Oils - metabolism; polyphenols; Polyphenols - metabolism; prostaglandins; Rats; Rats, Wistar; virgin olive oil; virgin olive oil; tyrosol; hydroxytyrosol; neuroprotection; oxidative stress
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/acs.jafc.5b00627

The neuroprotective effect of virgin olive oil (VOO) polyphenols has been related to their antioxidant effect. The main objective was to analyze how tyrosol and hydroxytyrosol contribute to the antioxidant and neuroprotective effects of VOO in a model of hypoxia–reoxygenation in rat brain slices. Rats were treated per os (po) (10 or 20 mg/kg/day) with hydroxytyrosol ethyl ether (HTEE), tyrosol ethyl ether (TEE), or 3,4-di-o-methylidene-hydroxytyrosol ethyl ether (MHTEE), used as a negative control for antioxidant effects. Lipid peroxidation was inhibited with HTEE, TEE, and MHTEE (from 5.0 ± 1.5 to 2.6 ± 1.5, 4.5 ± 1.5, and 4.8 ± 1.5 nmol/mg protein, respectively). However, all three compounds had similar neuroprotective effects: from 2.8 ± 0.07 to 1.8 ± 0.02 arbitrary units for HTEE, 1.4 ± 0.09 arbitrary units for TEE, and 1.3 ± 0.2 arbitrary units for MHTEE. All three compounds inhibited 3-nitrotyrosine production (from 3.7 ± 0.3 to 1.2 ± 0.03 nmol/0.1 g tissue for HTEE, 1.0 ± 0.2 nmol/0.1 g tissue for TEE, and 1.3 ± 0.1 nmol/0.1 g tissue for MHTEE), prostaglandin E2 production (from 55.7 ± 2.2 to 46.4 ± 1.9 pg/0.1 g tissue for HTEE, 24.7 ± 1.3 pg/0.1 g tissue for TEE, and 27.6 ± 2.6 pg/0.1 g tissue for MHTEE), whereas only HTEE inhibited IL1β production (from 35.7 ± 1.5 to 21.6 ± 0.8 pg/0.1 g tissue). Pearson correlation coefficients related neuroprotective effect with an antioxidant effect for HTEE (R = 0.72, p < 0.001), and inhibition of nitrosative stress (R = 0.78, 0.67, and 0.66 for HTEE, TEE, and MHTEE, respectively, p < 0.001) and inflammatory mediators (R = 0.72, 0.79, and 0.64 for HTEE, TEE, and MHTEE, respectively, p < 0.001) with all three compounds.