J Nutr Biochem. 2008 Aug;19(8):514-23. Epub 2007 Sep 27.

Antiatherogenicity of extra virgin olive oil and its enrichment with green tea polyphenols in the atherosclerotic apolipoprotein-E-deficient mice: enhanced macrophage cholesterol efflux.

Rosenblat M, Volkova N, Coleman R, Almagor Y, Aviram M.

Source

The Lipid Research Laboratory, Technion Faculty of Medicine, The Rappaport Family Institute for Research in the Medical Sciences, Rambam Medical Center, Haifa 31096, Israel.

Abstract

The antiatherogenic properties of extra virgin olive oil (EVOO) enriched with green tea polyphenols (GTPPs; hereafter called EVOO-GTPP), in comparison to EVOO, were studied in the atherosclerotic apolipoprotein-E-deficient (E0) mice. E0 mice (eight mice in each group) consumed EVOO or EVOO-GTPP (7 microl/mouse/day, for 2 months) by gavage feeding. The placebo group received only water. At the end of the study, blood samples, peritoneal macrophages and aortas were collected. Consumption of EVOO or EVOO-GTPP resulted in a minimal increase in serum total and high-density lipoprotein (HDL) cholesterol levels (by 12%) and in serum paraoxonase 1 activity (by 6% and 10%). EVOO-GTPP (but not EVOO) decreased the susceptibility of the mouse serum to AAPH-induced lipid peroxidation (by 18%), as compared to the placebo-treated mice. The major effect of both EVOO and EVOO-GTPP consumption was on HDL-mediated macrophage cholesterol efflux. Consumption of EVOO stimulated cholesterol efflux rate from mouse peritoneal macrophages (MPMs) by 42%, while EVOO-GTPP increased it by as much as 139%, as compared to MPMs from placebo-treated mice. Finally, the atherosclerotic lesion size of mice was significantly reduced by 11% or 20%, after consumption of EVOO or EVOO-GTPP, respectively. We thus conclude that EVOO possesses beneficial antiatherogenic effects, and its enrichment with GTPPs further improved these effects, leading to the attenuation of atherosclerosis development.

PMID:

17904345

For more information please visit:

http://www.ncbi.nlm.nih.gov/pubmed/17904345

[PubMed - indexed for MEDLINE]

Olive Polyphenols and Age and Disease Memory Deficits

J Alzheimers Dis. 2011 Sep 28. [Epub ahead of print]

Extra Virgin Olive Oil Improves Learning and Memory in SAMP8 Mice.

Farr SA, Price TO, Dominguez LJ, Motisi A, Saiano F, Niehoff ML, Morley JE, Banks WA, Ercal N, Barbagallo M.

Source

Geriatric Research Educational and Clinical Center (GRECC), VA Medical Center, St. Louis, MO, USA Department of Internal Medicine, Division of Geriatric Medicine, St. Louis University School of Medicine, St. Louis, MO, USA.

Abstract

Polyphenols are potent antioxidants found in extra virgin olive oil (EVOO); antioxidants have been shown to reverse age- and disease-related learning and memory deficits. We examined the effects of EVOO on learning and memory in SAMP8 mice, an age-related learning/memory impairment model associated with increased amyloid-β protein and brain oxidative damage. We administered EVOO, coconut oil, or butter to 11 month old SAMP8 mice for 6 weeks. Mice were tested in T-maze foot shock avoidance and one-trial novel object recognition with a 24 h delay. Mice which received EVOO had improved acquisition in the T-maze and spent more time with the novel object in one-trial novel object recognition versus mice which received coconut oil or butter. Mice that received EVOO had improve T-maze retention compared to the mice that received butter. EVOO increased brain glutathione levels suggesting reduced oxidative stress as a possible mechanism. These effects plus increased glutathione reductase activity, superoxide dismutase activity, and decreased tissue levels of 4-hydroxynoneal and 3-nitrotyrosine were enhanced with enriched EVOO (3 × and 5 × polyphenols concentration). Our findings suggest that EVOO has beneficial effects on learning and memory deficits found in aging and diseases, such as those related to the overproduction of amyloid-β protein, by reversing oxidative damage in the brain, effects that are augmented with increasing concentrations of polyphenols in EVOO.

PMID:

21955812

 

For more information please visit:

http://www.ncbi.nlm.nih.gov/pubmed/21955812

[PubMed - as supplied by publisher]

Atherosclerosis. 1996 Feb;120(1-2):15-23.

Dietary non-tocopherol antioxidants present in extra virgin olive oil increase the resistance of low density lipoproteins to oxidation in rabbits.

Wiseman SA, Mathot JN, de Fouw NJ, Tijburg LB.

Source

Unilever Research Laboratory, Vlaardingen, The Netherlands.

Abstract

Consumption of a range of dietary antioxidants may be beneficial in protecting low density lipoprotein (LDL) against oxidative modification, as studies have demonstrated that antioxidants other than vitamin E may also function against oxidation of LDL in vitro. In the present study, the effect of polyphenol antioxidants on the susceptibility of LDL to copper-mediated oxidation was investigated after feeding semi-purified diets to 3 groups of New Zealand white (NZW) rabbits. All diets comprised 40% energy as fat with 17% energy as oleic acid. Dietary fatty acid compositions were identical. Oils with different polyphenol contents were used to provide the dietary source of oleic acid-refined olive oil, extra virgin olive oil and Trisun high oleic sunflower seed oil. Polyphenolic compounds (hydroxytyrosol and p-tyrosol) could only be detected in the extra virgin olive oil. Vitamin E was equalised in all diets. LDL oxidizability in vitro was determined by continuously monitoring the copper-induced formation of conjugated dienes after 6 weeks of experimental diet feeding. The lag phase before demonstrable oxidation occurred was significantly increased in the high polyphenol, extra virgin olive oil group (P < 0.05) when compared with combined results from the low polyphenol group (refined olive oil and Trisun), even though the LDL vitamin E concentration in the high polyphenol group was significantly lower. The rate of conjugated diene formation was not influenced by the presence of dietary polyphenols. Results demonstrate that antioxidants, possibly phenolic compounds which are present only in extra virgin olive oil, may contribute to the endogenous antioxidant capacity of LDL, resulting in an increased resistance to oxidation as determined in vitro.

PMID:

8645356

[PubMed - indexed for MEDLINE]

For more information please visit:
http://www.ncbi.nlm.nih.gov/pubmed/8645356

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Int J Vitam Nutr Res. 2009 May;79(3):152-65.

Antioxidant activity of olive polyphenols in humans: a review.

Raederstorff D.

Source

DSM Nutritional Products Ltd, Department of Human Nutrition and Health, Basel, Switzerland. Daniel.Raederstorff@dsm.com

Abstract

In vitro and animal studies show that polyphenols from olives have potent antioxidant activities; 50 % of the phenolic compounds contained in olives and virgin olive oil are hydroxytyrosol and derivatives thereof. Hydroxytyrosol is the major olive polyphenol consumed and well absorbed in humans. It is considered to have the highest antioxidant potency compared to the other olive polyphenols. Review of the human intervention studies showed that olive polyphenols decreased the levels of oxidized-LDL in plasma and positively affected several biomarkers of oxidative damage. The antioxidant effects of olive polyphenols on low-density lipoprotein (LDL) oxidation are observed after a dietary intake of about 10 mg per day. The overall evidence from in vitro assays, and animal and human studies support the antioxidant effect of olive polyphenols. However, further larger human studies are needed to clarify the effect of olive polyphenols on markers of oxidative stress, particularly DNA damage and plasma isoprostane levels.

PMID:

20209466

[PubMed - indexed for MEDLINE]

For more information please visit: http://www.ncbi.nlm.nih.gov/pubmed/20209466

Food Chem Toxicol. 2006 Jul;44(7):903-15. Epub 2006 Mar 13.

Safety assessment of aqueous olive pulp extract as an antioxidant or antimicrobial agent in foods.

Soni MG, Burdock GA, Christian MS, Bitler CM, Crea R.

Source

Burdock Group, 2001 9th Avenue, Suite 301, Vero Beach, FL 32960, USA.

Abstract

The olive fruit, its oil and the leaves of the olive tree have a rich history of nutritional, medicinal and ceremonial uses. Olive oil, table olives and olive products are an important part of the Mediterranean diet, the greatest value of which may be due to olive polyphenols that contribute to the modulation of the oxidative balance in vivo. The objective of this review is to examine the available safety/toxicity literature on olive polyphenols, particularly hydroxytyrosol, to determine the safety-in-use of a standardized aqueous olive pulp extract (HIDROX). Among the polyphenols found in the extract, the major constituent of biological significance is hydroxytyrosol (50-70%). In oral bioavailability studies, urinary excretion of hydroxytyrosol and its glucuronide was found to be associated with the intake of hydroxytyrosol. Oral bioavailability of hydroxytyrosol in olive oil and in an aqueous solution was reported as 99% and 75%, respectively. In comparative studies, urinary excretion of hydroxytyrosol was greater in humans than in rats. The LD(50) of the extract and hydroxytyrosol was reported to be greater than 2000 mg/kg. In a subchronic study, the no observed adverse effect level (NOAEL) of the extract in rats was found to be 2000 mg/kg/day. In developmental and reproductive toxicity studies, HIDROX did not cause toxicity at levels up to 2000 mg/kg/day. In an in vivo micronucleus assay, oral exposure of rats to HIDROX at dose levels up to 5000 mg/kg/day for 29 days did not induce increases in polychromatic erythrocytes in bone marrow. Based on the available studies of the extract and polyphenols, and a history of exposure and use of components of the extract through table olives, olive products and olive oil, the consumption of HIDROX is considered safe at levels up to 20 mg/kg/day.


For more Information  please visit: http://www.ncbi.nlm.nih.gov/pubmed

Scientific Publication of Olive Polyphenols and Hydroxytyrosol

Genes Nutr. 2011 Sep 28. [Epub ahead of print]

Investigation into the biological properties of the olive polyphenol, hydroxytyrosol: mechanistic insights by genome-wide mRNA-Seq analysis.

Rafehi H, Smith AJ, Balcerczyk A, Ziemann M, Ooi J, Loveridge SJ, Baker EK, El-Osta A, Karagiannis TC.

Source

Epigenomic Medicine, Baker IDI Heart and Diabetes Institute, The Alfred Medical Research and Education Precinct, 75 Commercial Road, Melbourne, VIC, Australia.

Abstract

The medicinal properties of the leaves and fruit of Olea Europaea (olive tree) have been known since antiquity. Numerous contemporary studies have linked the Mediterranean diet with increased health. In particular, consumption of olive oil has been associated with a decreased risk of cardiovascular disease and certain cancers. Increasingly, there has been an interest in the biological properties of polyphenols, which are minor constituents of olive oil. For example, hydroxytyrosol has been shown to be a potent antioxidant and has anti-atherogenic and anti-cancer properties. The overall aim of this study was to provide insights into the molecular mechanisms of action of hydroxytyrosol using genome-wide mRNA-Seq. Initial experiments were aimed at assessing cytotoxicity, apoptosis and cell cycle effects of hydroxytyrosol in various cell lines. The findings indicated a dose-dependent reduction in cell viability in human erythroleukemic K562 and human keratinocytes. When comparing the viability in parental CEM-CCRF and R100 cells (which overexpress the P-glycoprotein pump), it was determined that the R100 cells were more resistant to effects of hydroxytyrosol suggesting efflux by the multi-drug resistance pump. By comparing the uptake of Hoechst 33342 in the two cell lines that had been pretreated with hydroxytyrosol, it was determined that the polyphenol may have P-glycoprotein-modulating activity. Further, initial studies indicated modest radioprotective effects of relatively low doses of hydroxytyrosol in human keratinocytes. Analysis of mRNA sequencing data identified that treatment of keratinocytes with 20 μM hydroxytyrosol results in the upregulation of numerous antioxidant proteins and enzymes, including heme oxygenase-1 (15.46-fold upregulation), glutaredoxin (1.65) and glutathione peroxidase (1.53). This may account for the radioprotective activity of the compound, and reduction in oxidative stress suggests a mechanism for chemoprevention of cancer by hydroxytyrosol. Alteration in the expression of transcription factors may also contribute to the anti-cancer effects described in numerous studies. These include changes in the expression of STAT3, STAT6, SMAD7 and ETS-1. The telomerase subunit TERT was also found to be downregulated in K562 cells. Overall, our findings provide insights into the mechanisms of action of hydroxytyrosol, and more generally, we identify potential gene candidates for further exploration.

PMID:

21953375

[PubMed - as supplied by publisher]

For more information please visit: http://www.ncbi.nlm.nih.gov/pubmed/21953375