Influence on hazelnut oil administration on peroxidation status of erythrocytes and apolipoprotein B 100-containing lipoproteins in rabbits fed on a high cholesterol diet

Monitoring of Hazelnut oil quality during thermal processing in comparison with extra virgin olive oil by using ATR-FTIR spectroscopy combined with chemometrics

Hazelnut oil (HO), which is not widely used because its healthy properties are not fully known yet, is an excellent nutrient due to its high content of monounsaturated fatty acids and antioxidants. In this study, the effects of thermal processing on the quality of HO in comparison to extra virgin olive oil (EVOO), which is one of the healthiest and heat-resistant oils, were investigated using Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy. Oil samples were heated at a frying temperature (180 °C) for 24 h in periods of 8 h per day and alterations in the spectra of these oils sampled every 2 h were evaluated. The heating process caused decreases in the areas of the bands at 3007 and 722 cm^-1 and the area ratios of 3007/2854 and 722/2854 cm^-1 and increases in the areas of the bands at 987 and 965 cm^-1 and the area ratio of 965/2854 cm^-1 in both oils suggesting the conjugation and cis-trans isomerization of unsaturated fatty acids. In addition, heating caused increases in the areas of the bands at 3475 and 1744 cm^-1 and the ratios of 3475/2854 cm^-1 and 1744/2854 cm^-1, a shift to a lower value in the wavenumber and a broadening of the 1744 cm^-1 band indicating the formation of primary and secondary oxidation products in the heated oils, which were also supported by chemical studies. Most of these changes began earlier in EVOO and all occurred to a higher extent, revealing that HO has a higher thermal stability than EVOO. Principal component analysis and hierarchical cluster analysis confirmed that HO is more resistant to heat than EVOO. These results showed that HO is superior to EVOO and it could be used for frying as a healthier and cheaper oil alternative. This study also indicated that oil oxidation could be monitored easily and rapidly via ATR-FTIR spectroscopy.

Artichoke leaf extract reduces oxidative stress and lipoprotein dyshomeostasis in rats fed on high cholesterol diet

Hypercholesterolemia and lipid peroxidation play complementary role in atherosclerosis. Artichoke leaf extract (ALE) is rich in natural antioxidants and has a cholesterol-reducing effect. However, there is no study investigating the effect of ALE on lipid levels and lipid peroxidation in experimental hypercholesterolemic conditions. Rats were fed on 4% (w/w) cholesterol and 1% (w/w) cholic acid supplemented diet for 1 month. ALE (1.5 g/kg/day) was given by gavage during the last 2 weeks. Serum lipid composition, malondialdehyde (MDA) and diene conjugate (DC) levels and plasma antioxidant activity (AOA) were measured. In addition, endogenous DC and copper-induced MDA levels were determined in apo B-containing lipoproteins (LDL+VLDL fraction). Serum cholesterol and triglyceride levels and the ratio of cholesterol to HDL-cholesterol decreased due to ALE treatment in rats fed on HC diet. Significant decreases in serum MDA and DC levels and increases in plasma AOA were detected in serum in ALE-treated hypercholesterolemic rats. Endogenous DC and copper-induced MDA levels were also lower in LDL+VLDL fraction due to ALE-treatment in hypercholesterolemic rats. Our results indicate that ALE may be useful for the prevention of hypercholesterolemia-induced pro-oxidant state in LDL+VLDL fraction and the reduction of increased serum cholesterol and triglyceride levels.

Effect of artichoke leaf extract on hepatic and cardiac oxidative stress in rats fed on high cholesterol diet

Hypercholesterolemia and lipid peroxidation play complementary roles in atherosclerosis. Artichoke (Cynara scolymus L., Asteraceae) leaf extract (ALE), rich in antioxidants, has cholesterol-reducing effect. We investigated the effect of ALE on serum and hepatic lipid levels and pro-oxidant-antioxidant balance in the liver and heart of hypercholesterolemic rats. Rats were fed on 4% (w/w) cholesterol and 1% cholic acid (w/w) supplemented diet for 1 month. ALE (1.5 g/kg/day) was given by gavage during the last 2 weeks. High cholesterol (HC) diet caused significant increases in serum and liver cholesterol and triglyceride levels. It increased malondialdehyde (MDA) and diene conjugate (DC) levels in both tissues. Hepatic vitamin E levels and hepatic and cardiac glutathione peroxidase (GSH-Px) activities decreased, but superoxide dismutase and glutathione transferase activities, glutathione, and vitamin C levels remained unchanged due to HC diet. Serum cholesterol and triglyceride levels and ratio of cholesterol to high-density lipoprotein (HDL)-cholesterol decreased in ALE plus HC-treated rats, but liver cholesterol and triglyceride levels remained unchanged. Significant decreases in hepatic and cardiac MDA and DC levels and increases in hepatic vitamin E and GSH-Px activities were observed in ALE-treated hypercholesterolemic rats. Our results indicate that ALE decreases serum lipids and hypercholesterolemia-induced pro-oxidant state in both tissues.