The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Marta Herraiz - One of the best experts on this subject based on the ideXlab platform.
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rapid analysis of free erythrodiol and Uvaol in olive oils by coupled reversed phase liquid chromatography gas chromatography
Journal of Agricultural and Food Chemistry, 1998Co-Authors: Gracia Patricia Blanch, Jesus Villen, Marta HerraizAbstract:On-line coupling of reversed phase liquid chromatography and gas capillary chromatography (RPLC−GC) using a programmed temperature vaporizer (PTV) as interface is used for the direct analysis of erythrodiol and Uvaol of edible oils by direct injection (i.e., without the need for prior enrichment of the sample). The reported procedure allows 2000 μL volume fractions of aqueous methanol eluents to be transferred into the GC system, 2000 μL/min being the speed of sample introduction. Relative standard deviations lower than 1.5% and detection limits lower than 1 ppm were obtained. The proposed method can be used to determine extra virgin olive oil adulterations as detection of an addition (10% (w/w)) of a solvent extracted oil to a cold pressed oil was achieved in less than 40 min on the basis of the determination of erythrodiol and Uvaol. Keywords: On-line coupled RPLC-GC; erythrodiol; Uvaol; direct analysis; olive oils
Jesus Villen - One of the best experts on this subject based on the ideXlab platform.
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analysis of unsaponifiable compounds of edible oils by automated on line coupling reversed phase liquid chromatography gas chromatography using the through oven transfer adsorption desorption interface
Journal of Agricultural and Food Chemistry, 2006Co-Authors: Jose M Cortes, Jesus Villen, Raquel Sanchez, Ana VazquezAbstract:An automated method for analysis of unsaponifiable compounds in edible oils is presented. The method involves the on-line coupling of reversed-phase liquid chromatography and gas chromatography (LC-GC) using the through oven transfer adsorption desorption (TOTAD) interface. The oil is injected directly with no sample pretreatment step other than filtration. It may also be considered to dilute the oil sample. In the LC step, a short C4 column using a methanol/water eluent separates analytes from the other components of the oils, which are made up of mainly triglycerides. A LC fraction of up to 1.6 mL containing the analytes is transferred to GC at a flow rate of 0.1-2 mL/min. The TOTAD interface allows solvent venting and the introduction of the analytes into the GC column. The proposed fully automated method allows the analysis of different groups of compounds (free sterols, tocopherols, squalene, and erythrodiol and Uvaol) in one chromatographic run or the analysis of these compounds in different groups. Sensitivity is more than necessary, and repeatability is good, the CV ranging from 3 to 12% for the full analysis.
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rapid analysis of free erythrodiol and Uvaol in olive oils by coupled reversed phase liquid chromatography gas chromatography
Journal of Agricultural and Food Chemistry, 1998Co-Authors: Gracia Patricia Blanch, Jesus Villen, Marta HerraizAbstract:On-line coupling of reversed phase liquid chromatography and gas capillary chromatography (RPLC−GC) using a programmed temperature vaporizer (PTV) as interface is used for the direct analysis of erythrodiol and Uvaol of edible oils by direct injection (i.e., without the need for prior enrichment of the sample). The reported procedure allows 2000 μL volume fractions of aqueous methanol eluents to be transferred into the GC system, 2000 μL/min being the speed of sample introduction. Relative standard deviations lower than 1.5% and detection limits lower than 1 ppm were obtained. The proposed method can be used to determine extra virgin olive oil adulterations as detection of an addition (10% (w/w)) of a solvent extracted oil to a cold pressed oil was achieved in less than 40 min on the basis of the determination of erythrodiol and Uvaol. Keywords: On-line coupled RPLC-GC; erythrodiol; Uvaol; direct analysis; olive oils
Gabriel Beltrán - One of the best experts on this subject based on the ideXlab platform.
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bioactive properties of the main triterpenes found in olives virgin olive oil and leaves of olea europaea
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Cristina Sanchezquesada, Alicia Lopezbiedma, Fernando Warleta, Gabriel Beltrán, Maria G Campos, José J. GaforioAbstract:Oleanolic acid, maslinic acid, Uvaol, and erythrodiol are the main triterpenes present in olives, olive tree leaves, and virgin olive oil. Their concentration in virgin olive oil depends on the quality of the olive oil and the variety of the olive tree. These triterpenes are described to present different properties, such as antitumoral activity, cardioprotective activity, anti-inflammatory activity, and antioxidant protection. Olive oil triterpenes are a natural source of antioxidants that could be useful compounds for the prevention of multiple diseases related to cell oxidative damage. However, special attention has to be paid to the concentrations used, because higher concentration may lead to cytotoxic or biphasic effects. This work explores all of the bioactive properties so far described for the main triterpenes present in virgin olive oil.
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triterpenic content and chemometric analysis of virgin olive oils from forty olive cultivars
Journal of Agricultural and Food Chemistry, 2009Co-Authors: Yosra Allouche, Marino Uceda, Antonio Jiménez, José J. Gaforio, Paz M Aguilera, Gabriel BeltránAbstract:Forty olive cultivars (Olea europaea, L.) from the World Olive Germoplasm Bank Collection of Cordoba (Spain) were studied for their oil triterpenic dialcohol (Uvaol and erythrodiol) and acid (oleanolic, ursolic, maslinic) composition. Dialcohol content ranged from 8.15 to 85.05 mg/kg, erythrodiol being the most predominant (from 5.89 to 73.78 mg/kg), whereas Uvaol content was found at lower levels (from 1.50 to 19.35 mg/kg). Triterpenic acid concentration oscillated between 8.90 to 112.36 mg/kg. Among them, ursolic acid was found at trace levels, while the mean values of oleanolic and maslinic acids ranged from 3.39 to 78.83 mg/kg and 3.93 to 49.81 mg/kg, respectively. The variability observed for both triterpenic dialcohols and acid content was emphasized by principal component and cluster analyses. Both analyses were able to discriminate between oil samples, especially by erythrodiol, oleanolic acid, and maslinic acids. Regarding these results, we conclude that the virgin olive oil triterpenic fraction can be considered as a useful tool to characterize monovarietal virgin olive oil.
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How heating affects extra virgin olive oil quality indexes and chemical composition
Journal of Agricultural and Food Chemistry, 2007Co-Authors: Yosra Allouche, Marino Uceda, Antonio Jiménez, José J. Gaforio, Gabriel BeltránAbstract:Two monovarietal extra virgin olive oils from Arbequina and Picual cultivars were subjected to heating at 180 degrees C for 36 h. Oxidation progress was monitored by measuring oil quality changes (peroxide value and conjugated dienes and trienes), fatty acid composition, and minor compound content. Tocopherols and polyphenols were the most affected by the thermal treatment and showed the highest degradation rate although their behavior was different for each cultivar. Alpha-tocopherol loss was more important in Arbequina oil whereas, total phenol content loss was greater in Picual oil. The later showed an important decrease in hydroxytyrosol (3,4-DHPEA) and its secoiridoid derivatives (3,4-DHPEA-EDA and 3,4-DHPEA-EA), while lignans decrease was lesser. For Arbequina oil these compounds remained stable, and a lowering tendency was observed for tyrosol (p-HPEA) and its derivatives (p-HPEA-EDA and p-HPEA-EA). In general, flavone content showed a decrease during heating, being higher for Arbequina oil. On the other hand, oleic acid, sterols, squalene, and triterpenic alcohols (erythrodiol and Uvaol) and acids (oleanolic and maslinic) were quite constant, exhibiting a high stability against oxidation. From these results, we can conclude that despite the heating conditions, VOO maintained most of its minor compounds and, therefore, most of its nutritional properties.
Eva E Rufinopalomares - One of the best experts on this subject based on the ideXlab platform.
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antiproliferative and pro apoptotic effect of Uvaol in human hepatocarcinoma hepg2 cells by affecting g0 g1 cell cycle arrest ros production and akt pi3k signaling pathway
Molecules, 2020Co-Authors: Gloria C Bonelperez, Amalia Perezjimenez, Isabel Griscardenas, Alberto M Parraperez, Jose A Lupianez, Fernando J Reyeszurita, Eva Siles, Rene Csuk, Juan Peragon, Eva E RufinopalomaresAbstract:Natural products have a significant role in the development of new drugs, being relevant the pentacyclic triterpenes extracted from Olea europaea L. Anticancer effect of Uvaol, a natural triterpene, has been scarcely studied. The aim of this study was to understand the anticancer mechanism of Uvaol in the HepG2 cell line. Cytotoxicity results showed a selectivity effect of Uvaol with higher influence in HepG2 than WRL68 cells used as control. Our results show that Uvaol has a clear and selective anticancer activity in HepG2 cells supported by a significant anti-migratory capacity and a significant increase in the expression of HSP-60. Furthermore, the administration of this triterpene induces cell arrest in the G0/G1 phase, as well as an increase in the rate of cell apoptosis. These results are supported by a decrease in the expression of the anti-apoptotic protein Bcl2, an increase in the expression of the pro-apoptotic protein Bax, together with a down-regulation of the AKT/PI3K signaling pathway. A reduction in reactive oxygen species (ROS) levels in HepG2 cells was also observed. Altogether, results showed anti-proliferative and pro-apoptotic effect of Uvaol on hepatocellular carcinoma, constituting an interesting challenge in the development of new treatments against this type of cancer.
Ana Vazquez - One of the best experts on this subject based on the ideXlab platform.
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analysis of unsaponifiable compounds of edible oils by automated on line coupling reversed phase liquid chromatography gas chromatography using the through oven transfer adsorption desorption interface
Journal of Agricultural and Food Chemistry, 2006Co-Authors: Jose M Cortes, Jesus Villen, Raquel Sanchez, Ana VazquezAbstract:An automated method for analysis of unsaponifiable compounds in edible oils is presented. The method involves the on-line coupling of reversed-phase liquid chromatography and gas chromatography (LC-GC) using the through oven transfer adsorption desorption (TOTAD) interface. The oil is injected directly with no sample pretreatment step other than filtration. It may also be considered to dilute the oil sample. In the LC step, a short C4 column using a methanol/water eluent separates analytes from the other components of the oils, which are made up of mainly triglycerides. A LC fraction of up to 1.6 mL containing the analytes is transferred to GC at a flow rate of 0.1-2 mL/min. The TOTAD interface allows solvent venting and the introduction of the analytes into the GC column. The proposed fully automated method allows the analysis of different groups of compounds (free sterols, tocopherols, squalene, and erythrodiol and Uvaol) in one chromatographic run or the analysis of these compounds in different groups. Sensitivity is more than necessary, and repeatability is good, the CV ranging from 3 to 12% for the full analysis.
