Evolution of Hydroxytyrosol, Hydroxytyrosol 4-ß-d-Glucoside, 3,4-Dihydroxyphenylglycol and Tyrosol in Olive Oil Solid Waste or "Alperujo".

The main by-product generated from the olive oil two-phase extraction system, or alperujo, is undoubtedly a rich source of bioactive components, among which phenolics are one of the most important. The evolution of four of its main phenolics: hydroxytyrosol (HT), hydroxytyrosol 4-ß-d-glucoside (Glu-HT), 3,4-dihydroxyphenylglycol (DHPG) and tyrosol (Ty) was studied over two seasons and in ten oil mills under similar climatological and agronomic conditions, for the first time using organic extraction and high-performance liquid chromatography (HPLC-DAD) determination. The results show that HT (200-1600 mg/kg of fresh alperujo) and Ty (10-570 mg/kg) increase, while DHPG (10-370 mg/kg) decreases only in the last month of the season and Glu-HT (1400-0 mg/kg) decreases drastically from the beginning. This evolution is similar between different seasons, with a high correlation between Glu-HT, HT, and Ty. On the other hand, it has been verified that a mixture of alperujos from all the oil mills, which is what the pomace extractor receives, is a viable source of a liquid fraction which is rich in the phenolics studied through organic extractions and especially after the application of a thermal treatment, obtaining values of 4.2 g/L of HT, 0.36 g/L of DHPG, and 0.49 g/L of Ty in the final concentrated liquid fraction.

Effect of a Triterpenoid-Rich Olive Oil on Chronic Kidney Disease in an Experimental Model of Diabetes Mellitus.

The aim of this study was to assess the effect of triterpenoids on the development of diabetic nephropathy in an experimental model of diabetes mellitus. For this purpose, a destoned and dehydrated olive oil (DDOO) was used, comparing its effects to a destoned olive oil (DOO). DDOO had a higher triterpenoid content than DOO but an equal content of alcoholic polyphenols. Four study groups (n = 10 animals/group) were formed: healthy rats, diabetic control rats (DRs), and DRs treated orally with 0.5 mL/kg/day of DOO or DDOO for two months. DRs showed impaired renal function (proteinuria, increased serum creatinine, decreased renal creatinine clearance) and morphology (glomerular volume and glomerulosclerosis). These alterations correlated with increased systemic and renal tissue oxidative stress and decreased prostacyclin production. DDOO administration significantly reduced all variables of renal damage, as well as systemic and renal oxidative stress, to a greater extent than the effect produced by DOO. In conclusion, triterpenoid-rich olive oil may prevent kidney damage in experimental diabetes mellitus.

Asparagus Roots: From an Agricultural By-Product to a Valuable Source of Fructans.

Asparagus roots are by-products from asparagus cultivation and they could be considered one of the best sources of fructans. These polymers are interesting food ingredients for their prebiotic and immuno-stimulating characteristics. The aim of this work is to characterize the fructan profile from the roots of several asparagus varieties grown at different locations and pickled at three vegetative statuses in order to valorize these by-products as fructan source. Fructans were extracted with hot water and fractionated into three pools according to their molecular weight (MW). Their average MW was studied by HPSEC and their degree of polymerization by HPAEC. The fructan content was up to 12.5% on fresh weight basis, depending on variety and sampling date. The relative abundance of the three pools also depended on the picking moment as after the spear harvest period their total content and MW increased. The average MW of the three fractions was similar among varieties with 4.8, 8.4 and 9 sugar units, although fructans up to 30 units were identified by HPAEC. These characteristics make them similar to the commercialized Orafti®-GR inulin, a common additive to food products. Therefore, the concept of asparagus roots as cultivation waste must be changed to a new feedstock for sustainable agriculture and industry.

Anti-Inflammatory and Antioxidant Activity of Hydroxytyrosol and 3,4-Dihydroxyphenyglycol Purified from Table Olive Effluents.

New liquid effluents based on the use of acetic acid in the table olive industry make it easier to extract bioactive compounds to be used for food, cosmetic, and pharmaceutical purposes. The use of water acidified with acetic acid or in brine with or without acetic acid for storing the table olive enhances the extraction of two more active phenolic compounds: hydroxytyrosol (HT) and 3,4-dihydroxyphenylglycol (DHPG). This work has two aims: (1) measure the solubilization of phenolics controlled for two years using more than thirty olive varieties with different ripeness index as a potential source of HT and DHPG, and (2) evaluate the anti-inflammatory activity of the purified phenolics. The effluents with a higher concentration of phenolics were used for the extraction of HT and DHPG in order to evaluate its antioxidant and anti-inflammatory activity in vitro by the determination of pro-inflammatory cytokines such as Human Tumor Necrosis Factor-α (TNF), Interleukin-6 (IL-6), and Interleukin-1ß (Il-1ß). The anti-inflammatory activity of these phenolic extracts was demonstrated by studying the expression of cytokines by qPCR and the levels of these proteins by enzyme-linked immunosorbent assay (ELISA).

From Green Technology to Functional Olive Oils: Assessing the Best Combination of Olive Tree-Related Extracts with Complementary Bioactivities.

Our aim was to assess the combination of olive tree-related extracts with the most favorable profile of in vitro bioactive properties. We tested the antioxidant (increment of low-density lipoprotein resistance against oxidation), vasoactive (promotion of nitric oxide release and decrease of endothelin-1 production in human umbilical vein endothelial cells), anti-inflammatory (decrease of the endothelial production of vascular cell adhesion molecule-1), and antithrombotic (reduction of the endothelial release of plasminogen activator inhibitor-1) capacities of six phenolic extracts and three triterpenic acid solutions (Ps and Ts, respectively). We tested extracts alone and in combination, at nutritional (Ps: 0.05-0.5 µmol/L; Ts: 0.001-0.1 µmol/L) and nutraceutical doses (Ps: 1-10 µmol/L; Ts: 0.25-10 µmol/L). The combination of Ps rich in 3,4-dihydroxyphenylglycol (76%, P2), hydroxytyrosol (95%, P3), and oleuropein (70%, P4) (final nutritional concentration: 0.15 µmol/L; final nutraceutical concentration: 3 µmol/L) was the best in order to prepare functional products and nutraceuticals with cardioprotective properties, despite the fact that the isolated extract with the greatest in vitro properties was P5 (75% oleocanthal), suggesting a potential synergistic effect among different olive components.

Cardioprotective Effect of a Virgin Olive Oil Enriched with Bioactive Compounds in Spontaneously Hypertensive Rats.

Olive oil and its derivatives have been described to exert beneficial effects on hypertensive states and cardiovascular disease prevention. We studied the effects of chronic consumption of extra virgin olive oil (EVOO), enriched in bioactive compounds from olive fruit and leaves, on blood pressure, endothelial function, oxidative and inflammatory status, and circulating cholesterol levels, in spontaneously hypertensive rats (SHR). Thirty SHR were randomly assigned to three groups: a control untreated SHR group, an SHR group (1 mL/rat/day) of a control olive oil (17.6 mg/kg of phenolic compounds), and an SHR group (1 mL/rat/day) of the enriched EVOO (750 mg/kg of phenolic compounds) for eight weeks. Ten Wistar Kyoto rats (WKY) were included as healthy controls. Long-term administration of the enriched EVOO decreased systolic blood pressure and cardiac hypertrophy, and improved the ex vivo aortic endothelial dysfunction measured in SHR. Moreover, enriched oil supplementation reduced the plasma levels of Angiotensin II and total cholesterol, and the urinary levels of endothelin-1 and oxidative stress biomarkers, while pro-inflammatory cytokines were unaffected. In conclusion, sustained treatment with EVOO, enriched in bioactive compounds from the olive fruit and leaves, may be an effective tool for reducing blood pressure and cholesterol levels alone or in combination with pharmacological anti-hypertensive treatment.

Saponin profile of green asparagus genotypes.

The main goal of this study was to determine the saponin profiles of different "triguero" asparagus genotypes and to compare them to green asparagus commercial hybrids. The samples consisted of 31 commercial hybrids and 58 genotypes from the Huétor-Tájar (HT) population variety ("triguero"). The saponin analysis by high-performance liquid chromatography-mass spectrometry allowed for the determination of 12 saponins derived from a furostan-type steroidal genin, 4 of which had never been described in the edible part of asparagus. The saponin profile of "triguero" asparagus was a combination of these new saponins and protodioscin. Although protodioscin was the major saponin found in commercial hybrids, some of these 12 saponins were detected as major components in some of the commercial hybrids. The total contents of saponins described in some of these HT genotypes reach values as high as 10-100 times higher than those found in commercial hybrids.

Optimization of a method for the profiling and quantification of saponins in different green asparagus genotypes.

The main goal of this study was the optimization of a HPLC-MS method for the qualitative and quantitative analysis of asparagus saponins. The method includes extraction with aqueous ethanol, cleanup by solid phase extraction, separation by reverse phase chromatography, electrospray ionization, and detection in a single quadrupole mass analyzer. The method was used for the comparison of selected genotypes of Huétor-Tájar asparagus landrace and selected varieties of commercial diploid hybrids of green asparagus. The results showed that while protodioscin was almost the only saponin detected in the commercial hybrids, eight different saponins were detected in the Huétor-Tájar asparagus genotypes. The mass spectra indicated that HT saponins are derived from a furostan type steroidal genin having a single bond between carbons 5 and 6 of the B ring. The total concentration of saponins was found to be higher in triguero asparagus than in commercial hybrids.