lignans and oleuropein

The effect of the composition of twelve varieties of extra virgin olive oils (EVOOs) on their differentiation based in agronomic criteria and on the antioxidant capacity was studied. Principal component analysis permitted an overview of the samples and their compositions, showing evidence of grouping and correlation between antioxidant capacity, oleuropein and ligstroside derivatives (OLD) and specific extinction at 270. Oleic and linoleic acids, 3,4-DHPEA-EA and p-HPEA-EDA (OLD), unsaturated/saturated ratio and induction time (IT) allowed the correct classification of samples according to year of harvest, ripening stage and variety. The antioxidant capacity of EVOOs was satisfactory predicted through a partial least square model based on ΔK, hydroxytyrosol, pinoresinol, oleuropein derivate and IT. Validation of the model gave a correlation R>0.83 and an error of 7% for independent samples. This model could be a useful tool for the olive industry to highlight the nutritional quality of EVOOs and improve their marketing.

Topics: Agriculture; Antioxidants; Chile; Food Analysis; Furans; Glucosides; Iridoid Glucosides; Iridoids; Least-Squares Analysis; Lignans; Olive Oil; Phenylethyl Alcohol; Principal Component Analysis; Pyrans

Enriching oils, such as olive oil, could be one solution to tackle the worldwide epidemic of vitamin D deficiency and to better fit with omega 3 (DHA) recommendations. However, data regarding the interactions occurring at the intestinal level between vitamin D and phenols from olive oil are scarce. We first determined the effect of polyphenols from a virgin olive oil, and a virgin olive oil enriched with DHA, on vitamin D absorption in rats. We then investigated the effects of 3 main olive oil phenols (oleuropein, hydroxytyrosol and pinoresinol) on vitamin D uptake by Caco-2 cells. The presence of polyphenols in the olive oil supplemented with DHA inhibited vitamin D postprandial response in rats (-25%, p<0.05). Similar results were obtained with a mix of the 3 polyphenols delivered to Caco-2 cells. However, this inhibitory effect was due to the presence of pinoresinol only. As the pinoresinol content can highly vary between olive oils, the present results should be taken into account to formulate an appropriate oil product enriched in vitamin D.

Topics: Animals; Caco-2 Cells; Docosahexaenoic Acids; Female; Furans; Humans; Intestinal Absorption; Iridoid Glucosides; Iridoids; Lignans; Olive Oil; Phenylethyl Alcohol; Polyphenols; Rats; Rats, Wistar; Vitamin D

The present study was aimed to assess the in vivo acute effects of oleuropein or/and pinoresinol, polyphenols widely diffused in natural sources, on rat pial microvascular responses during transient BCCAO and reperfusion.. Rat pial microcirculation was visualized by fluorescence microscopy through a closed cranial window. Pial arterioles were classified into five orders of branching. Capillaries were assigned order 0, the smallest arterioles order 1 and the largest ones order 5.. Rats subjected to BCCAO and reperfusion showed: arteriolar diameter decrease, microvascular leakage, leukocyte adhesion in venules, and reduction in capillary perfusion. Pretreatment with oleuropein or pinoresinol, a higher dose before BCCAO determined dilation in all arteriolar orders RE. Microvascular leakage was reduced as well as leukocyte adhesion and ROS formation, while capillary perfusion was protected. Inhibition of endothelium nitric oxide synthase prior to oleuropein or pinoresinol reduced the effect of these polyphenols on pial arteriolar diameter and leakage. These substances, administered together, prevented microvascular damage to a larger extent.. Oleuropein and pinoresinol were both able to protect pial microcirculation from I-reperfusion injury, to increase nitric oxide release and to reduce oxidative stress preserving pial blood flow distribution.

Topics: Animals; Arterioles; Brain Injuries; Cerebrovascular Circulation; Furans; Iridoid Glucosides; Iridoids; Lignans; Male; Microcirculation; Rats; Rats, Wistar; Reperfusion Injury; Vasodilator Agents

Potato, tomato, eggplant and pumpkin were deep fried, sautéed and boiled in Mediterranean extra virgin olive oil (EVOO), water, and a water/oil mixture (W/O). We determined the contents of fat, moisture, total phenols (TPC) and eighteen phenolic compounds, as well as antioxidant capacity in the raw vegetables and compared these with contents measured after cooking. Deep frying and sautéing led to increased fat contents and TPC, whereas both types of boiling (in water and W/O) reduced the same. The presence of EVOO in cooking increased the phenolics identified in the raw foods as oleuropein, pinoresinol, hydroxytyrosol and tyrosol, and the contents of vegetable phenolics such as chlorogenic acid and rutin. All the cooking methods conserved or increased the antioxidant capacity measured by DPPH, FRAP and ABTS. Multivariate analyses showed that each cooked vegetable developed specific phenolic and antioxidant activity profiles resulting from the characteristics of the raw vegetables and the cooking techniques.

Topics: Antioxidants; Benzothiazoles; Chlorogenic Acid; Chromatography, High Pressure Liquid; Cluster Analysis; Cooking; Cucurbita; Dietary Fats; Furans; Iridoid Glucosides; Iridoids; Lignans; Multivariate Analysis; Olive Oil; Phenols; Phenylethyl Alcohol; Rutin; Solanum lycopersicum; Solanum melongena; Solanum tuberosum; Sulfonic Acids; Vegetables

The aim of this work was to study the chemical characteristics of two Tunisian cultivars, namely Dhokar and Gemri-Dhokar, to analyse the fatty acids, sterols, triacylglycerols, triterpenic alcohols, and to determine the phenolic composition and oxidative stability.. Among the rare varieties, Gemri-Dhokar olive oil had the highest value of oleic acid (69.39%) whereas Dhokar oil was noteworthy for its lower content of phenolic compounds (94.56 mg kg(-1) gallic acid equivalents of oil) and presented the highest level of palmitic acid (19.37%). The main sterols found in all olive oil samples were β-sitosterol and Δ5-avenasterol, whereas cholesterol and 24-methylenecholesterol were also found in all samples but in lower amounts. Two triterpenic dialcohols (erythrodiol and uvaol) were also detected and their content ranged from 1.45 to 2.30%, in Gemri-Dhokar and Dhokar olive oil, respectively. Ten phenolic compounds were identified. In all samples, the main phenols found were oleuropein aglycon and pinoresinol. These phenolic compounds showed significant correlations with oxidative stability.. The analytical parameters of two oils that were determined in this study were greatly influenced by genetic factors (cultivar).

Topics: Alcohols; Drug Stability; Fatty Acids; Furans; Iridoid Glucosides; Iridoids; Lignans; Oleanolic Acid; Olive Oil; Oxidation-Reduction; Palmitic Acid; Phenols; Phytosterols; Plant Oils; Pyrans; Sitosterols; Species Specificity; Triglycerides; Triterpenes; Tunisia

The characterisation of virgin olive oils from two Tunisian cultivars, growing in the Tataouin zone, namely Jemri-Bouchouka, a rare olive cultivar, and Chemlali-Tataouin, was carried out. Several analytical parameters were evaluated; these include quality index, fatty acids, phenolic, chlorophyll, carotenoid, squalene, α-tocopherol compositions and oxidative stability.. Jemri-Bouchouka olive oil had the highest value of oleic acid (74.50%) while Chemlali-Tataouin olive oil had the highest value of oleic acid (69.39 %) and also was characterized by a high percentage of palmitic acid (14.75 %) which makes this oil freeze at a low temperature [corrected]. On the other hand, Jemri-Bouchouka oil was characterised by a low phenolic and α-tocopherol content (267.72 mg GAE kg⁻¹ and 278.34 mg kg⁻¹, respectively). Ten phenolic compounds were identified. The main phenols found in the two olive oils were oleuropein aglycon and pinoresinol. All phenolic compounds showed significant correlations with oxidative stability.. The analytical parameters of virgin olive oil that were determined in this study were greatly influenced by cultivar.

Topics: alpha-Tocopherol; Antioxidants; Fatty Acids; Food Quality; Food Storage; Fruit; Furans; Hydrogen-Ion Concentration; Iridoid Glucosides; Iridoids; Lignans; Lipid Peroxides; Olea; Oleic Acid; Olive Oil; Oxidation-Reduction; Palmitic Acid; Phenols; Pigments, Biological; Plant Oils; Pyrans; Species Specificity; Transition Temperature; Tunisia

A capillary zone electrophoresis method has been carried out to determine and quantitate some compounds of the polyphenolic fraction of virgin olive oil which have never previously been determined before using capillary electrophoresis, such as elenolic acid, ligstroside aglycon, oleuropein aglycon, and (+)-pinoresinol. The compounds were identified using standards obtained by semipreparative high-performance liquid chromatography (HPLC). A detailed method optimization was performed to separate the phenolic compounds present in olive oil using a methanol-water extract of Picual extra-virgin olive oil, and different extraction systems were compared (C18-solid phase extraction (SPE), Diol-SPE, Sax-SPE and liquid-liquid extraction). The optimized parameters were 30 mM sodium tetraborate buffer (pH 9.3) at 25 kV with 8 s hydrodynamic injection, and the quantitation was carried out by the use of two reference compounds at two different wavelengths.

Topics: Chromatography, High Pressure Liquid; Electrophoresis, Capillary; Flavonoids; Furans; Glucosides; Iridoid Glucosides; Iridoids; Lignans; Olive Oil; Phenols; Phenylethyl Alcohol; Plant Oils; Polyphenols; Pyrans