The endogenous synthesis of lipids, which requires suitable dietary raw materials, is critical for the formation of membrane bilayers. In eukaryotic cells, phospholipids are the predominant membrane lipids and consist of hydrophobic acyl chains attached to a hydrophilic head group. The relative balance between saturated, monounsaturated, and polyunsaturated acyl chains is required for the organization and normal function of membranes. Virgin olive oil is the richest natural dietary source of the monounsaturated lipid oleic acid and is one of the key components of the healthy Mediterranean diet. Virgin olive oil also contains a unique constellation of many other lipophilic and amphipathic constituents whose health benefits are still being discovered. The focus of this review is the latest evidence regarding the impact of oleic acid and the minor constituents of virgin olive oil on the arrangement and behavior of lipid bilayers. We highlight the relevance of these interactions to the potential use of virgin olive oil in preserving the functional properties of membranes to maintain health and in modulating membrane functions that can be altered in several pathologies. This article is part of a Special Issue entitled: Membrane Structure and Function: Relevance in the Cell's Physiology, Pathology and Therapy.

Asparagus (Asparagus officinalis L.) by-products, which represent around 50% of the processed vegetable, are a potential source of dietary fibre. The way that these byproducts are treated affects the composition and functional properties of fibre-rich powders. Factors such as treatment intensity, solvent, and drying system were studied. Only the more soluble components (soluble sugars, uronic acids and proteins) showed significant differences. All the fibre-rich powders had a high concentration of TDF (62-77%). The IF/SF proportion decreased with the severity of treatment, and increasing in this way the physiological quality of the fibre. Functional properties-water holding capacity (WHC), oil holding capacity (OHC), solubility (SOL), and glucose dialysis retardation index (GDRI)-varied according to the obtaining procedure. WHC and GDRI were higher in intensely extracted fibres, due to the effect of thermal processing. WHC had similar values (11-20 mL water/g powder) than those described for other agricultural by-products, but OHC and GDRI were much higher (5-8 mL oil/g powder and 25-45%, respectively). These properties make fibre-rich powders from asparagus by-products a valuable source of dietary fibre to be included in the formulation of fibreenriched foods.

The aim of this study was to determine whether isorhamnetin, an immediate 3'-O-methylated metabolite of quercetin, affects proliferation, cell death, and the cell cycle of human colon carcinoma (HCT-116) cells. Isorhamnetin was found to be a potent antiproliferative agent in a dose- and time-dependent manner, with an IC50 of 72 μM after 48 h of incubation as estimated by MTT assay. Flow cytometry and fluorescence microscopy analysis showed that isorhamnetin exerted a stimulatory effect on apoptosis and necrosis. Isorhamnetin also increased the number of cells in G2/M phase. Serum deprivation appeared to potentiate the effects of isorhamnetin on cell death and facilitated cell cycle progression to G0/G1 phase. These results suggest that isorhamnetin might mediate inhibition of HCT-116 cell growth through the perturbation of cell cycle progression and are consistent with the notion that G2/M checkpoints could be a conserved target for flavonoids in human colon cancer cells, leading to apoptotic and necrotic death. These antiproliferative, apoptotic, necrotic, and cell cycle effects suggest that isorhamnetin may have clinically significant therapeutic and chemopreventive capabilities. To our knowledge, this is the first report of the effect of isorhamnetin on human colon cancer cells.

Three different methods (antiradical activity, inhibition of primary oxidation, and ferric reducing power) have been used to evaluate the antioxidant activity of eight different asparagus cultivars and byproducts: white and green asparagus from Alcalá del Río (Guadalquivir Valley, Seville) and American hybrids, native spears, and their byproducts from Huétor-Tájar (Vega de Granada). The correlation between antioxidant activity and total phenol content was studied. Six standards were also tested to validate the modified methods for antioxidant activity determination. Results obtained for antiradical capacity and reducing power were very similar, and a high correlation with phenols was found (R > or = 0.9 for both tests). Sample origin was an important factor, spears from Huétor-Tájar having higher values (ARC between 7 and 10 and P(R) of 0.25-0.33) than those from Alcalá del Río (ARC 0.6-2 and P(R) of 0.05-0.07). Significant differences were found between spears with the same origin, suggesting that genetics are another factor to take into account. Asparagus inhibits lipid primary oxidation, but no correlation between the inhibition percentage and phenols was observed. Asparagus origin was the only factor that led to significant differences: samples from Huétor-Tájar had higher values (POIC between 18 and 32) than those from Alcalá del Río (POIC of 5-9). Byproducts from the canning industry at Huétor-Tájar were also assayed for antioxidant activity; the results obtained suggested that byproducts could be considered as an excellent source of natural antioxidants.