Olive Leaf Extract Attenuates Cardiac, Hepatic, and Metabolic Changes in High Carbohydrate–, High Fat–Fed Rats

Abstract

Olive oil, an important component of the Mediterranean diet, produces cardioprotective effects, probably due to both oleic acid and the polyphenols such as oleuropein and hydroxytyrosol. Our aim in this study was to assess whether a polyphenol-enriched extract from the leaves of Olea europaea L. with oleuropein as the major component attenuated the cardiovascular, hepatic, and metabolic signs of a high-carbohydrate, high-fat (HCHF) diet (carbohydrate, 52%; fat, 24%, 25% fructose in drinking water) in rats. Male Wistar rats were fed either a cornstarch diet (CS) or a HCHF diet for a total of 16 wk. Diets of the treatment groups [CS+olive leaf extract (OLE) and HCHF+OLE] were supplemented with 3% OLE after 8 wk of being fed their respective CS or HCHF diets for a further 8 wk. After 16 wk, HCHF rats developed signs of metabolic syndrome, including elevated abdominal and hepatic fat deposition, collagen deposition in heart and liver, cardiac stiffness, and oxidative stress markers (plasma malondialdehyde and uric acid concentrations), with diminished aortic ring reactivity, abnormal plasma lipid profile, impaired glucose tolerance, and hypertension. Compared with HCHF rats, those in the HCHF+OLE group had improved or normalized cardiovascular, hepatic, and metabolic signs with the exception of elevated blood pressure. These results strongly suggest that an OLE containing polyphenols such as oleuropein and hydroxytyrosol reverses the chronic inflammation and oxidative stress that induces the cardiovascular, hepatic, and metabolic symptoms in this rat model of diet-induced obesity and diabetes without changing blood pressure.

Nutrigenomics and Atherosclerosis: The Postprandial and Long-Term Effects of Virgin Olive Oil Ingestion

“…Changes in the expression of all of these genes, except POLK, were particularly observed when VOO, rich in polyphenols, was present in the TMD. The decrease in gene expression associated with inflammatory that was observed in this study agrees with previous studies that have reported a decrease in systemic inflammatory markers and oxidative stress due to the ingestion of polyphenols from olive oil and olive leaf extract (Poudyal et al, 2010;Puel et al, 2008). IFN-is considered to be a key inflammatory mediator and the release of this cytokine is regulated by polyphenols from red wine and dietary tea polyphenols (Deng et al, 2010;Magrone et al, 2008).…”

Effects of Dietary Addition of a Low-Pectin Apple Fibre Preparation on Rats

“…Numerous studies have reported that high fructose and lard contents in the diet are associated with various unfavourable metabolic disturbances in rodents, such as hyperlipidemia and hyperinsulinemia [Buettner et al, 2006;Poudyal et al, 2010]. It is noteworthy, however, that lard was the sole dietary source of fat in the present study, thus rats were deprived of essential fatty acids for 2 weeks.…”

Olive leaf extract modulates permethrin induced genetic and oxidative damage in rats

“…At the same time olive leaves have been heavily exploited for the prevention or the treatment of hypertension, carcinogenesis, diabetes, atherosclerosis, gingivitis and many other traditional therapeutic uses (Han et al 2009;Haloui et al 2010;Bouallagui et al 2011). Poudyal et al (2010) reported that olive leaf extract (OLE) containing polyphenols such as oleuropein and hydroxytyrosol reversed the chronic inflammation and oxidative stress by diet-induced obesity and diabetes in cardiovascular, hepatic, and metabolic symptoms in rats. In additon, OLE possessed gastroprotective activity against cold restraint stress-induced gastric lesions in rats, possibly related to its antioxidative properties (Dekanski et al 2009).…”