title: Hypolipidimic and antioxidant activities of oleuropein and its hydrolysis derivative-rich extracts from Chemlali olive leaves.
abstract: Oleuropein-rich extracts from olive leaves and their enzymatic and acid hydrolysates, respectively rich in oleuropein aglycone and hydroxytyrosol, were prepared under optimal conditions. The antioxidant activities of these extracts were examined by a series of models in vitro. In this study the lipid-lowering and the antioxidative activities of oleuropein, oleuropein aglycone and hydroxytyrosol-rich extracts in rats fed a cholesterol-rich diet were tested. Wistar rats fed a standard laboratory diet or cholesterol-rich diets for 16 weeks were used. The serum lipid levels, the thiobarbituric acid reactive substances (TBARS) level, as indicator of lipid peroxidation, and the activities of liver antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)) were examined. The cholesterol-rich diet induced hyperlipidemia resulting in the elevation of total cholesterol (TC), triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C). Administration of polyphenol-rich olive leaf extracts significantly lowered the serum levels of TC, TG and LDL-C and increased the serum level of high-density lipoprotein cholesterol (HDL-C). Furthermore, the content of TBARS in liver, heart, kidneys and aorta decreased significantly after oral administration of polyphenol-rich olive leaf extracts compared with those of rats fed a cholesterol-rich diet. In addition, these extracts increased the serum antioxidant potential and the hepatic CAT and SOD activities. These results suggested that the hypocholesterolemic effect of oleuropein, oleuropein aglycone and hydroxytyrosol-rich extracts might be due to their abilities to lower serum TC, TG and LDL-C levels as well as slowing the lipid peroxidation process and enhancing antioxidant enzyme activity.
authors.affiliation: Laboratoire des Bioprocédés, Pôle d'excellence régional AUF (PER-LBP), Centre de biotechnologie de Sfax (CBS), BP 1177, 3038 Sfax, Tunisia.
authors.forename: Hedya
authors.initials: H
authors.lastname: Jemai
authors.forename: Mohamed
authors.initials: M
authors.lastname: Bouaziz
authors.forename: Ines
authors.initials: I
authors.lastname: Fki
authors.forename: Abdelfattah
authors.initials: A
authors.lastname: El Feki
authors.forename: Sami
authors.initials: S
authors.lastname: Sayadi
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D002374:Catalase / Q000378:metabolism; D002791:Cholesterol, Dietary / Q000008:administration & dosage / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D006321:Heart / Q000187:drug effects; D006851:Hydrochloric Acid / Q000378:metabolism; D006868:Hydrolysis / Q000187:drug effects; D006937:Hypercholesterolemia / Q000139:chemically induced / Q000188:drug therapy / Q000517:prevention & control*; D057888:Iridoid Glucosides; D039823:Iridoids; D015227:Lipid Peroxidation / Q000187:drug effects*; D008055:Lipids / Q000097:blood; D008099:Liver / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D008297:Male; D015394:Molecular Structure; D031658:Olea / Q000737:chemistry*; D009929:Organ Size / Q000187:drug effects; D010626:Phenylethyl Alcohol / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D011714:Pyrans / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D001617:beta-Glucosidase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D002791:Cholesterol, Dietary; D057888:Iridoid Glucosides; D039823:Iridoids; D008055:Lipids; D010936:Plant Extracts; D011714:Pyrans; D017392:Thiobarbituric Acid Reactive Substances; C005975:3,4-dihydroxyphenylethanol; C002769:oleuropein; D002374:Catalase; D013482:Superoxide Dismutase; D001617:beta-Glucosidase; D010626:Phenylethyl Alcohol; D006851:Hydrochloric Acid