Effect of the olive oil phenol hydroxytyrosol on human hepatoma HepG2 cells
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Scientific evidence suggests that olive oil’s beneficial effects are related to the high level of antioxidants, including phenolic compounds such as hydroxytyrosol. In vivo studies have shown that olive oil HTy is bioavailable and its biological activities, similar to those reported for other natural antioxidants such as quercetin, include prevention of LDL oxidation. Previous studies from our laboratory have shown that HTy and other phenolics in olive oil are absorbed and metabolized by cultured human hepatoma HepG2 cells where glucuronidated and methylated conjugates were the main derivatives formed, resembling the metabolic profile of olive oil phenols observed in human plasma and urine.
Aim of the study
The effect of olive oil phenol (HTy) on cell viability and redox status of cultured HepG2 cells, and the protective effect of HTy against an oxidative stress induced by tert-butylhydroperoxide (t-BOOH) were investigated.
Lactate dehydrogenase activity as marker for cell integrity, concentration of reduced glutathione (GSH), generation of reactive oxygen species (ROS) and activity of the antioxidant enzyme glutathione peroxidase (GPx) as markers of redox status and determination of malondialdehyde (MDA) as marker of lipid peroxidation were measured.
No changes in cell integrity or intrinsic antioxidant status resulted from a direct treatment with 10–40 μM HTy. Pre-treatment of HepG2 with 10–40 μM HTy for 2 or 20 h completely prevented cell damage as well as the decrease of reduced glutathione and increase of malondialdehyde evoked by t-BOOH in HepG2 cells. Reactive oxygen species generation and the significant increase of glutathione peroxidase activity induced by t-BOOH were greatly reduced when cells were pretreated with HTy.
The results clearly show that treatment of HepG2 cells with the olive oil phenolic HTy may positively affect their antioxidant defense system, favoring cell integrity and resistance to cope with a stressful situation.
Keywordsbioactive compounds dietary antioxidants olive oil phenolics liver cell culture antioxidant defenses biomarkers for oxidative stress
R. Mateos was a postdoctoral fellow from the Ministerio de Educación y Ciencia. We thank Dr. J.L. Espartero (University of Seville, Spain) for kindly providing hydroxytyrosol.
- 3.Mateos R, Espartero JL, Trujillo M, Ríos JJ, León-Camacho M, Alcudia F, Cert A (2001) Determination of phenols, flavones, and lignans in virgin olive oils by solid-phase extraction and high-performance liquid chromatography with diode array ultraviolet detection. J Agric Food Chem 49:2185–2192CrossRefGoogle Scholar
- 4.Owen R, Mier W, Giacosa A, Hull WE, Spiegelhalder B, Bartsch H (2000) Identification of lignans as major components in the phenolic fraction of olive oil. Clin Chem 46:976–988Google Scholar
- 6.Caruso D, Visioli F, Patelli R, Galli C, Galli G (2001) Urinary excretion of olive oil phenols and their metabolites in humans. Metab Clin Exp 50:1426–1428Google Scholar
- 7.Vissers MH, Zock PL, Roodenburg AJ, Leenen R, Katan MB (2002) Olive oil phenols are absorbed in humans. J Nutr 132:409–417Google Scholar
- 9.D’Angelo S, Manna C, Migliardi V, Mazzoni O, Morrica P, Capasso G, Pontoni G, Galletti P, Zappia V (2001) Pharmacokinetics and metabolism of hydroxytyrosol, a natural antioxidant from olive oil. Drug Metab Dispos 29:1492–1498Google Scholar
- 10.Tuck KL, Freeman MP, Hayball PJ, Stretch GL, Stupans I (2001) The in vivo fate of hydroxytyrosol and tyrosol, antioxidant phenolic constituents of olive oil, following intravenous and oral dosing of labelled compounds to rats. J Nutr 131:1993–1996Google Scholar
- 15.Manna C, Galletti P, Cucciolla V, Moltedo O, Leone A, Zappia V (1997) The protective effect of the olive oil polyphenols (3,4-dihydroxyphenyl)-ethanol counteracts reactive oxygen metabolite-induced cytotoxicity in Caco-2 cells. J Nutr 127:286–292Google Scholar
- 18.Caruso D, Berra B, Giavarini F, Cortesi N, Fedeli E, Galli G (1999) Effect of virgin olive oil phenolic compounds on in vitro oxidation of human low density lipoproteins. Nutr Metab Cardiovasc Dis 9:102–107Google Scholar
- 19.Scaccini C, Nardini M, D’Aquino M, Gentili V, Di Felice M, Tomassi G (1992) Effect of dietary oils on lipid peroxidation and on antioxidant parameters of rat plasma and lipoprotein fractions. J Lipid Res 33:627–633Google Scholar
- 23.Baraldi PG, Simoni D, Manfredini S, Menziani E (1983) Preparation of 3,4-dihydroxy-1-benzeneethanol: a reinvestigation. Liebigs Ann Chem 684–686Google Scholar
- 26.Vasault A (1987) Lactate dehydrogenase. UV-method with pyruvate and NADH. In: Bergmeyer HV (ed) Methods of enzymatic analysis. Weinheim, Verlag-Chemie, pp. 118–133Google Scholar
- 27.Welder AA, Acosta D (1994) Enzyme leakage as an indicator of cytotoxicity in culture cells. In: Tyson CA, Franzier JM (eds) In vitro toxicity indicators: methods in toxicology. Academic press, New York, pp. 46–49Google Scholar
- 32.Gunzler WA, Kremers H, Flohe L (1974) An improved coupled test procedure for glutathione peroxidase. Klin Chem Klin Biochem 12:444–448Google Scholar
- 37.Murakami C, Hirakawa Y, Inui H, Nakano Y, Yoshida H (2002) Effects of epigallocatechin 3-O-gallate on cellular antioxidative system in HepG2 cells. J Nutr Sci Vitaminol 48:89–94Google Scholar
- 39.Scharf G, Prustomersky S, Knasmuller S, Schulte-Hermann R, Huber WW (2003) Enhancement of glutathione and g-glutamylcysteine synthetase, the rate limiting enzyme of glutathione synthesis, by chemoprotective plant-derived food and beverage components in the human hepatoma cell line HepG2. Nutr Cancer 45:74–83CrossRefGoogle Scholar
- 41.Viña J (1990) Glutathione: metabolism and physiological functions. CRC Press, BostonGoogle Scholar
- 43.Pilz J, Meineke I, Gleiter CH (2000) Measurement of free and bound malondialdehyde in plasma by high-performance liquid chromatography as the 2,4-dinitrophenylhydrazine derivative. J Chromatogr B 742:315–325Google Scholar
- 45.Suttnar J, Masova L, Dyr E (2001) Influence of citrate and EDTA anticoagulants on plasma malondialdehyde concentrations estimated by high-performance liquid chromatography. J Chromatogr B 751:193–119Google Scholar
- 46.Courtois F, Delvin E, Ledoux M, Seidman E, Lavoie JC, Levy E (2002) The antioxidant BHT normalizes some oxidative effects of iron + ascorbate on lipid metabolism in Caco-2 cells. J Nutr 132:1289–1292Google Scholar
- 50.Röhrdanz E, Ohler S, Tran-Thi Q-H, Kahl R (2002) The phytoestrogen daidzein affects the antioxidant enzyme system of rat hepatoma H4IIE cells. J Nutr 132:370–375Google Scholar