Active compounds extracted from extra virgin olive oil counteract mesothelial-to-mesenchymal transition of peritoneal mesothelium cells exposed to conventional peritoneal dialysate: in vitro and in vivo evidences

Qualitative and Quantitative Analysis of Phenolic Compounds in Spray-Dried Olive Mill Wastewater

The processing of olives for oil production generates the most abundant agro-industrial by-products in the Mediterranean area. The three-phase olive oil extraction process requires the addition of a large amount of water to the system, which is difficult to dispose of for its load of toxic pollutants. On the other hand, olive mill wastewater is a rich source of bioactive substances with various biological properties that can be used as ingredients in the food industry for obtaining functional and nutraceutical foods as well as in the pharmaceutical industry. In this study, we present the results relative to the phenolic compounds detected in dried olive mill wastewaters obtained using a spray dryer. Qualitative and quantitative analyses were obtained by high-pressure liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). In particular, the compounds here discussed are: apigenin (9.55 mg/kg dry weight), caffeic acid (2.89 mg/kg dry weight), catecol (6.12 mg/kg dry weight), p-cumaric acid (5.01 mg/kg dry weight), diosmetin (3.58 mg/kg dry weight), hydroxytyrosol (1.481 mg/kg dry weight), hydroxytyrosyl oleate (564 mg/kg dry weight), luteolin (62.38 mg/kg dry weight), luteolin-7-O-glucoside (88.55 mg/kg dry weight), luteolin-4-O-glucoside (11.48 mg/kg dry weight), oleuropein (103 mg/kg dry weight), rutin (48.52 mg/kg dry weight), tyrosol (2043 mg/kg dry weight), vanillin (27.70 mg/kg dry weight), and verbascoside (700 mg/kg dry weight). The results obtained highlighted that the use of dehumidified air as a drying medium, with the addition of maltodextrin, appears to be an effective way to produce a phenol-rich powder to be included in food formulations as well as in pharmaceutical preparations having different biological properties.

Dried Destoned Virgin Olive Pomace: A Promising New By-Product from Pomace Extraction Process

At present the olive oil industry produces large amounts of secondary products once considered waste or by-products. In this paper, we present, for the first time, a new interesting olive by-product named “dried destoned virgin olive pomace” (DDVOP), produced by the pomace oil industry. The production of DDVOP is possible thanks to the use of a new system that differs from the traditional ones by having the dryer set at a lower temperature value, 350 °C instead of 550 °C, and by avoiding the solvent extraction phase. In order to evaluate if DDVOP may be suitable as a new innovative feeding integrator for animal feed, its chemical characteristics were investigated. Results demonstrated that DDVOP is a good source of raw protein and precious fiber; that it is consistent in total phenols (6156 mg/kg); rich in oleic (72.29%), linoleic (8.37%) acids and tocopherols (8.80 mg/kg). A feeding trial was, therefore, carried out on sheep with the scope of investigating the influence of the diet on the quality of milk obtained from sheep fed with DDVOP-enriched feed. The resulting milk was enriched in polyunsaturated (0.21%) and unsaturated (2.42%) fatty acids; and had increased levels of phenols (10.35 mg/kg) and tocopherols (1.03 mg/kg).

Polyphenols Attenuate Highly-Glycosylated Haemoglobin-Induced Damage in Human Peritoneal Mesothelial Cells

We investigated the cytoprotective role of the dietary polyphenols on putative damage induced by Amadori adducts in Human Peritoneal Mesothelial Cells (HPMCs). Increased accumulation of early products of non-enzymatic protein glycation-Amadori adducts-in the peritoneal dialysis fluid due to their high glucose, induces severe damage in mesothelial cells during peritoneal dialysis. Dietary polyphenols reportedly have numerous health benefits in various diseases and have been used as an efficient antioxidant in the context of several oxidative stress-related pathologies. HPMCs isolated from different patients were exposed to Amadori adducts (highly glycated haemoglobin, at physiological concentrations), and subsequently treated with several polyphenols, mostly presented in our Mediterranean diet. We studied several Amadori-induced effects in pro-apoptotic and oxidative stress markers, as well as the expression of several pro-inflammatory genes (nuclear factor-kappaB, NF-kB; inducible Nitric Oxide synthetase, iNOS), different caspase-activities, level of P53 protein or production of different reactive oxygen species in the presence of different polyphenols. In fact, cytoprotective agents such as dietary polyphenols may represent an alternate approach to protect mesothelial cells from the cytotoxicity of Amadori adducts. The interference with the Amadori adducts-triggered mechanisms could represent a therapeutic tool to reduce complications associated with peritoneal dialysis in the peritoneum, helping to maintain peritoneal membrane function longer in patients undergoing peritoneal dialysis.

Eco-Friendly Extraction and Characterisation of Nutraceuticals from Olive Leaves

Olive tree (Olea europaea L.) leaf, a waste by-product of the olive oil industry, is an inexpensive and abundant source of biophenols of great interest for various industrial applications in the food supplement, cosmetic, and pharmaceutical industries. In this work, the aqueous extraction of high-added value compounds from olive leaves by using microfiltered (MF), ultrapure (U), and osmosis-treated (O) water was investigated. The extraction of target compounds, including oleuropein (Olp), hydroxytyrosol (HyTyr), tyrosol (Tyr), verbascoside (Ver), lutein (Lut), and rutin (Rut), was significantly affected by the characteristics of the water used. Indeed, according to the results of liquid chromatography tandem mass spectrometry, the extracting power of microfiltered water towards rutin resulted very poor, while a moderate extraction was observed for oleuropein, verbascoside, and lutein. On the other hand, high concentrations of hydroxytyrosol were detected in the aqueous extracts produced with microfiltered water. The extraction power of ultrapure and osmosis-treated water proved to be very similar for the bio-active compounds oleuropein, verbascoside, lutein, and rutin. The results clearly provide evidence of the possibility of devising new eco-friendly strategies based on the use of green solvents which can be applied to recover bioactive compounds from olive leaves.