[Olive oil and inhibition of low density lipoprotein oxidation. Role of phenolic compounds].
BACKGROUND
To investigate the protective effect of several olive oils with different phenolic composition on low density lipoprotein susceptibility to oxidation.


METHODS
Refined olive oil (phenolic content: 0 mg/l caffeic acid equivalents [CAE]), common olive oil (0.1 and 0.3 mg/l CAE), and virgin olive oil diluted with refined olive oil (0.1 y 0.3 mg/l CAE), were added to isolated low density lipoprotein. Conjugated dienes formation was monitored after copper-mediated low density lipoprotein oxidation.


RESULTS
An increase in the lag time of conjugated dienes formation after copper-mediated low density lipoprotein oxidation was observed linked to olive oil phenolic content (p < 0.0001, ANOVA). Multiple regression analysis showed that phenolics were the most significant antioxidants with 0.1 mg/l--increase in phenolic concentration, adjusted for alpha-tocopherol and beta-carotene, was 72 minutes (95% confidence interval [CI] 64 to 80 min) for common olive oil, and 111 min (CI 95%: 100-123 min) for virgin olive oil. In common olive oil alpha-tocopherol levels were significatively associated with the increase in the lag time (p = 0.003), reaching in virgin olive oil a borderline significant (p = 0.084).


CONCLUSIONS
Olive oil containing phenolics showed more antioxidant effect on low density lipoprotein oxidation than refined olive in relation to its phenolic content. The nature of the phenolic content influences the antioxidant capacity of an olive oil.
Fitó
M
M
Unidad de Lípidos y Epidemiología Cardiovascular, Institut Municipal d'Investigació Mèdica (IMIM), Barcelona.
Covas
M I
MI
Lamuela-Raventós
R M
RM
Vila
J
J
de la Torre
C
C
Marrugat
J
J
D000975:Antioxidants / Q000494:pharmacology*; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D016001:Confidence Intervals; D003300:Copper / Q000494:pharmacology; D004042:Dietary Fats, Unsaturated / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D008077:Lipoproteins, LDL / Q000378:metabolism*; D000069463:Olive Oil; D010084:Oxidation-Reduction; D010636:Phenols / Q000494:pharmacology*; D010938:Plant Oils / Q000494:pharmacology*; D012044:Regression Analysis; D013997:Time Factors; D014810:Vitamin E / Q000494:pharmacology; D019207:beta Carotene / Q000494:pharmacology
D000975:Antioxidants; D004042:Dietary Fats, Unsaturated; D008077:Lipoproteins, LDL; D000069463:Olive Oil; D010636:Phenols; D010938:Plant Oils; D019207:beta Carotene; D014810:Vitamin E; D003300:Copper