Hypocholesterolemic effects of phenolic extracts and purified hydroxytyrosol recovered from olive mill wastewater in rats fed a cholesterol-rich diet.
In our previous studies, a phenolic-rich extract of olive mill wastewaters (OMW) was prepared under optimal conditions, using a continuous countercurrent extraction unit, and hydroxytyrosol was purified from the obtained OMW extract. The antioxidant activity of OMW extract and hydroxytyrosol was determined by a series of models in vitro. In this study, the hypocholesterolemic effects of hydroxytyrosol and OMW extract in rats fed a cholesterol-rich diet were tested. Wistar rats, fed a standard laboratory diet or a cholesterol-rich diet for 16 weeks, were used. Serum lipid levels, as well as thiobarbituric acid reactive substances (TBARS) and superoxide dismutase and catalase activities in liver were examined. Cholesterol-rich diet-induced hypercholesterolemia was manifested in the elevation of serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C). Administration of a low-dose (2.5 mg/kg of body weight) of hydroxytyrosol and a high-dose (10 mg/kg of body weight) of OMW extract significantly lowered the serum levels of TC and LDL-C while increasing the serum levels of high-density lipoprotein cholesterol (HDL-C). Furthermore, the TBARS contents in liver, heart, kidney, and aorta decreased significantly after oral administration of hydroxytyrosol and OMW extract as compared with those of rats fed a cholesterol-rich diet. In addition, OMW phenolics increased CAT and SOD activities in liver. These results suggested that the hypocholesterolemic effect of hydroxytyrosol and OMW extract might be due to their abilities to lower serum TC and LDL-C levels as well as slowing the lipid peroxidation process and enhancing antioxidant enzyme activity.
Fki
Ines
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Laboratoire des Bioprocédés, Centre de Biotechnologie de Sfax (CBS), Route de Sidi Mansour km 6, 3038 Sfax, Tunisia.
Sahnoun
Zouhair
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Sayadi
Sami
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D000818:Animals; D000924:Anticholesteremic Agents / Q000008:administration & dosage*; D000975:Antioxidants / Q000032:analysis; D002374:Catalase / Q000378:metabolism; D002791:Cholesterol, Dietary / Q000008:administration & dosage*; D007220:Industrial Waste; D008055:Lipids / Q000097:blood; D008099:Liver / Q000201:enzymology; D008297:Male; D031658:Olea / Q000737:chemistry*; D010636:Phenols / Q000008:administration & dosage*; D010626:Phenylethyl Alcohol / Q000008:administration & dosage / Q000031:analogs & derivatives*; D010936:Plant Extracts / Q000008:administration & dosage*; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis
D000924:Anticholesteremic Agents; D000975:Antioxidants; D002791:Cholesterol, Dietary; D007220:Industrial Waste; D008055:Lipids; D010636:Phenols; D010936:Plant Extracts; D017392:Thiobarbituric Acid Reactive Substances; C005975:3,4-dihydroxyphenylethanol; D002374:Catalase; D013482:Superoxide Dismutase; D010626:Phenylethyl Alcohol