Phenolic-extract from argan oil (Argania spinosa L.) inhibits human low-density lipoprotein (LDL) oxidation and enhances cholesterol efflux from human THP-1 macrophages

2006 ◽  
Vol 184 (2) ◽  
pp. 389-396 ◽  
Author(s):  
Hicham Berrougui ◽  
Martin Cloutier ◽  
Maxim Isabelle ◽  
Abdelouahed Khalil
2007 ◽  
Vol 77 (1) ◽  
pp. 66-72 ◽  
Author(s):  
McEneny ◽  
Couston ◽  
McKibben ◽  
Young ◽  
Woodside

Raised total homocysteine (tHcy) levels may be involved in the etiology of cardiovascular disease and can lead to damage of vascular endothelial cells and arterial wall matrix. Folic acid supplementation can help negate these detrimental effects by reducing tHcy. Recent evidence has suggested an additional anti-atherogenic property of folate in protecting lipoproteins against oxidation. This study utilized both an in vitro and in vivo approach. In vitro: Very-low-density lipoprotein (VLDL) and low density lipoprotein (LDL) were isolated by rapid ultracentrifugation and then oxidized in the presence of increasing concentrations (0→ μmol/L) of either folic acid or 5-methyltetrahydrofolate (5-MTHF). In vivo: Twelve female subjects were supplemented with folic acid (1 mg/day), and the pre- and post-VLDL and LDL isolates subjected to oxidation. In vitro: 5-MTHF, but not folic acid, significantly increased the resistance of VLDL and LDL to oxidation. In vivo: Following folic acid supplementation, tHcy decreased, serum folate increased, and both VLDL and LDL displayed a significant increase in their resistance to oxidation. These results indicated that in vitro, only the active form of folate, 5-MTHF, had antioxidant properties. In vivo results demonstrated that folic acid supplementation reduced tHcy and protected both VLDL and LDL against oxidation. These findings provide further support for the use of folic acid supplements to aid in the prevention of atherosclerosis.


2007 ◽  
Vol 55 (25) ◽  
pp. 10437-10445 ◽  
Author(s):  
Yih-Shou Hsieh ◽  
Wu-Hsien Kuo ◽  
Ta-Wei Lin ◽  
Horng-Rong Chang ◽  
Teseng-His Lin ◽  
...  

1993 ◽  
Vol 294 (3) ◽  
pp. 829-834 ◽  
Author(s):  
M I Mackness ◽  
C Abbott ◽  
S Arrol ◽  
P N Durrington

1. The oxidation of low-density lipoprotein (LDL) is believed to play a central role in atherogenesis. We have compared the effect of antioxidant vitamins and high-density lipoprotein (HDL) on the Cu(2+)-catalysed oxidation of LDL. 2. Antioxidant vitamin supplementation significantly reduced conjugated diene formation but did not affect the formation of lipid peroxides. 3. Conversely, HDL did not affect conjugated diene formation but inhibited the formation of lipid peroxides by up to 90%. 4. The inhibition by HDL of lipid peroxide formation in oxidized LDL was dependent on the concentration of HDL and was not due to HDL chelating Cu2+. 5. Large interindividual variations in the inhibition of lipid peroxide formation by autologous HDL were evident, which were related to the rate of lipid peroxide generation in the LDL. 6. We conclude that HDL is a powerful antioxidant or more probably inhibitor of LDL oxidation in vitro and may play an important role in vivo in preventing atherosclerosis by inhibiting LDL oxidation in the artery wall.


2005 ◽  
Vol 109 (2) ◽  
pp. 189-197 ◽  
Author(s):  
Mike J. Sampson ◽  
Simon Braschi ◽  
Gavin Willis ◽  
Sian B. Astley

The HDL (high-density lipoprotein)-associated enzyme PON (paraoxonase)-1 protects LDL (low-density lipoprotein) from oxidative modification in vitro, although it is unknown if this anti-atherogenic action occurs in vivo. In a cross-sectional study of 58 Type II diabetic subjects and 50 controls, we examined the fasting plasma LDL basal conjugated diene concentration [a direct measurement of circulating oxLDL (oxidatively modified LDL)], lipoprotein particle size by NMR spectroscopy, PON-1 polymorphisms (coding region polymorphisms Q192R and L55M, and gene promoter polymorphisms −108C/T and −162G/A), PON activity (with paraoxon or phenyl acetate as the substrates) and dietary antioxidant intake. Plasma oxLDL concentrations were higher in Type II diabetic patients (males, P=0.048; females, P=0.009) and unrelated to NMR lipoprotein size, PON-1 polymorphisms or PON activity (with paraoxon as the substrate) in any group. In men with Type II diabetes, however, there was a direct relationship between oxLDL concentrations and PON activity (with phenyl acetate as the substrate; r=0.611, P=0.0001) and an atherogenic NMR lipid profile in those who were PON-1 55LL homozygotes. Circulating oxLDL concentrations in vivo were unrelated to PON-1 genotypes or activity, except in male Type II diabetics where there was a direct association between PON activity (with phenyl acetate as the substrate) and oxLDL levels. These in vivo data contrast with in vitro data, and may be due to confounding by dietary fat intake. Male Type II diabetic subjects with PON-1 55LL homozygosity have an atherogenic NMR lipid profile independent of LDL oxidation. These data do not support an in vivo action of PON on LDL oxidation.


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