Multiple pharmacological effects of olive oil phenols

Secoiridoids delivered as olive leaf extract induce acute improvements in human vascular function and reduction of an inflammatory cytokine: a randomised, double-blind, placebo-controlled, cross-over trial

The leaves of the olive plant (Olea europaea) are rich in polyphenols, of which oleuropein and hydroxytyrosol (HT) are most characteristic. Such polyphenols have been demonstrated to favourably modify a variety of cardiovascular risk factors. The aim of the present intervention was to investigate the influence of olive leaf extract (OLE) on vascular function and inflammation in a postprandial setting and to link physiological outcomes with absorbed phenolics. A randomised, double-blind, placebo-controlled, cross-over, acute intervention trial was conducted with eighteen healthy volunteers (nine male, nine female), who consumed either OLE (51 mg oleuropein; 10 mg HT), or a matched control (separated by a 4-week wash out) on a single occasion. Vascular function was measured by digital volume pulse (DVP), while blood collected at baseline, 1, 3 and 6 h was cultured for 24 h in the presence of lipopolysaccharide in order to investigate effects on cytokine production. Urine was analysed for phenolic metabolites by HPLC. DVP-stiffness index and ex vivo IL-8 production were significantly reduced (P< 0.05) after consumption of OLE compared to the control. These effects were accompanied by the excretion of several phenolic metabolites, namely HT and oleuropein derivatives, which peaked in urine after 8-24 h. The present study provides the first evidence that OLE positively modulates vascular function and IL-8 production in vivo, adding to growing evidence that olive phenolics could be beneficial for health.

Antiallergic effect of Picholine olive oil-in-water emulsions through β-hexosaminidase release inhibition and characterization of their physicochemical properties

The inhibitory effect of Picholine olive oil from Montpellier in Southern France on the chemical mediator release in type I allergy, using rat basophilic leukemia (RBL-2H3) cells, was investigated. Oil-in-water (O/W) emulsions prepared using Picholine olive oil showed an inhibitory effect on the chemical mediator release and decreased expressions of genes related to type I allergy in RBL-2H3 cells. We then measured the phenolic compounds present in Picholine olive oil using high-performance liquid chromatography and investigated some physical properties, such as droplet size, size distribution, viscosity, and surface tension of the resulting olive O/W emulsions. Our findings indicate that Picholine olive oil has high flavonoids content, especially apigenin, and the prepared emulsion of Picholine olive oil resulted in a considerable small size distribution, with an average droplet size of 170 nm.

Anti-proliferative and apoptotic effects of oleuropein and hydroxytyrosol on human breast cancer MCF-7 cells

Olive oil intake has been shown to induce significant levels of apoptosis in various cancer cells. These anti-cancer properties are thought to be mediated by phenolic compounds present in olive. These beneficial health effects of olive have been attributed, at least in part, to the presence of oleuropein and hydroxytyrosol. In this study, oleuropein and hydroxytyrosol, major phenolic compound of olive oil, was studied for its effects on growth in MCF-7 human breast cancer cells using assays for proliferation (MTT assay), cell viability (Guava ViaCount assay), cell apoptosis, cellcycle (flow cytometry). Oleuropein or hydroxytyrosol decreased cell viability, inhibited cell proliferation, and induced cell apoptosis in MCF-7 cells. Result of MTT assay showed that 200 mug/mL of oleuropein or 50 mug/mL of hydroxytyrosol remarkably reduced cell viability of MCF-7 cells. Oleuropein or hydroxytyrosol decrease of the number of MCF-7 cells by inhibiting the rate of cell proliferation and inducing cell apoptosis. Also hydroxytyrosol and oleuropein exhibited statistically significant block of G(1) to S phase transition manifested by the increase of cell number in G(0)/G(1) phase.

Saline water irrigation effects on fruit development, quality, and phenolic composition of virgin olive oils, cv. Chemlali

Field-grown olive trees (cv. Chemlali) were used over two growing seasons to determine the effect of different saline water irrigation levels on fruit development characteristics, yield, and virgin olive oil (VOO) quality. The plants were irrigated with fresh water (FW; ECe=1.2 dS m(-1)) and saline water (SS; ECe=7.5 dS m(-1)). Fruit weight, olive, and oil content decreased under irrigation with saline water. Total oil contents were 27.85 and 25.7% fresh weight (fw) during 2005 in FW and SS irrigated plants, respectively. However, major phenolic compounds (tyrosol, hydroxytyrosol, vanillic,...) and total phenol concentrations in VOO increased under saline water irrigation. In 2005, total phenol contents were 198 and 223 mg/kg of oil in FW and SS treatments, respectively. Furthermore, VOO from SS treated plants showed higher contents of oleic, linoleic, linolenic, and heptadecanoic acids than FW ones, and oil samples of both treatments were classified as "extra virgin".

Antidiabetic components contained in vegetables and legumes

Epidemiological analyses in a large Chinese population have revealed that consumption of vegetables and legumes is inversely associated with the risk of type 2 diabetes (T2D). However, the health benefits of these plants have not been fully explained, which stimulated our interest to identify antidiabetic components from vegetables and legumes through searching medicinal databases, especially those containing traditional Chinese medicines. The results not only provide meaningful clues to understanding the antidiabetic potentials of these plants but also display the possibility of pinpointing food component functions by searching medicinal databases.

How to understand the dichotomy of antioxidants

One of the most bewildering aspects of antioxidants is that their excellent in vitro activity cannot necessarily be translated into in vivo effect. Through summarizing the recent progresses made in free radical chemistry and biology, this dichotomy is tentatively explained in terms of the heterogeneity of biological systems and the interactions between antioxidants and surrounding molecules in vivo, which also has important implications for updating the current strategies for screening and designing antioxidant drugs.