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More and more attention is nowadays given to the possible translational application of a great number of biochemical and biological findings with the involved molecules. This is also the case of cholesterol oxidation products, redox molecules over the last years deeply investigated for their implication in human pathophysiology. Oxysterols of non-enzymatic origin, the excessive increase of which in biological fluids and tissues is of toxicological relevance for their marked pro-oxidant and pro-inflammatory properties, are increasingly applied in clinical biochemistry as molecular markers in the diagnosis and monitoring of several human and veterinary diseases. Conversely, oxysterols of enzymatic origin, the production of which is commonly under physiological regulation, could be considered and tested as promising pharmaceutical agents because of their antiviral, pro-osteogenic and antiadipogenic properties of some of them. Very recently, the quantification of oxysterols of non-enzymatic origin has been adopted in a systematic way to evaluate, monitor and improve the quality of cholesterol-based food ingredients, that are prone to auto-oxidation, as well as their industrial processing and the packaging and the shelf life of the finished food products. The growing translational value of oxysterols is here reviewed in its present and upcoming applications in various industrial fields., Graphical abstract CYP27A1: cholesterol 27-hydroxylase; CYP7A1: cholesterol 7-alpha-hydroxylase; CYP7B1: noxysterol 7-alpha-hydroxylase; CYP11A1: cholesterol side-chain cleavage enzyme; 25OHC: 25-hydroxycholesterol; 27OHC:27-hydroxycholesterol; 20SOHC: 20 (S)-hydroxycholesterol; 22ROHC:22(R)-hydroxycholesterol; 22SOHC:22(S)-hydroxycholesterol; 7 KC:7-ketocholesterol; 7βOHC:7β-hydroxycholesterol; α-epoxy:5α,6α-epoxide; β-epoxy:5β,6β-epoxide; triol:cholestan-3β,5α,6β-triol.Image 1

Oxysterols are formed in foods during processing and storage, having an impact on the nutritional profile besides being associated to the development of diverse chronic and degenerative diseases. This review provides an overview on recent information and knowledge gaps on oxysterol formation and absorption from foods. Their contents should be monitored based on dietary habits, in order to have more realistic data available and to expand the currently limited daily intake data. Unraveling the mechanism of oxysterol absorption, together with a more thorough understanding of their metabolism, is needed; in this respect, bioavailability studies using in vitro and in vivo methodologies could contribute with new insights. Finally, the food-health axis can be boosted by suitable technological solutions and antioxidants to help preventing also in vivo oxidation.

The effect of broccoli extract (BE)-enriched diet was studied in order to evaluate its ability to counteract liver cholesterol oxidation products (COPs) induced by acute strenuous exercise in rats. Thirty-two female Wistar rats were randomly divided into four groups: control diet without exercise (C), BE-enriched diet without exercise (B), control diet with acute exhaustive exercise (S) and BE-enriched diet with acute exhaustive exercise (BS). The study lasted 45 days and on the last day, rats of S and BS groups were forced to run until exhaustion on a treadmill. Glutathione-S-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GPx), catalase (CAT) and cholesterol oxidation products (COPs) were determined in liver. Exhaustive exercise was clearly responsible for tissue damage, as evidenced by the increase of lactate dehydrogenase (LDH) plasma activity increase in the S group rats. Moreover, the exercise protocol reduced CAT activity in liver, while it did not affect GST, GR and GPx. The BE-enriched diet increased raised GST, GR and CAT activities in rats of BS group. The main COPs found were 7α-hydroxycholesterol, 7β-hydroxycholesterol, 7-ketocholesterol, cholestanetriol, 24-hydroxycholesterol and 27-hydroxycholesterol. The BE-enriched diet led to reduced cholesterol oxidation following exhaustive exercise; the highest level of COPs was found in the S group, whereas the BS rats showed the lowest valueamount. This study indicates that the BE-enriched diet increases antioxidant enzyme activities and exerts an antioxidant effect towards cholesterol oxidation in rat liver, suggesting the use of phytochemicals in the prevention of oxidative damage and in the modulation of the redox environment.

Flaxseeds have been recently in focus due to the antioxidant capacity of some of their compounds. However, there is a lack of easily accessible information concerning their activity against lipid oxidation in food systems. Therefore, the aim of the study was to determine the effect of defatted meals (DFM) and the aqueous extracts (AFE) obtained from brown and golden flaxseeds on lipid oxidation in pork meatballs. Fatty acid composition, peroxide value (PV), thiobarbituric acid reactive substances (TBARS) and cholesterol content were monitored during 6 months of freezer storage. Cholesterol oxidation products were identified and quantified. Both DFM and AFE limited fatty acid and cholesterol oxidation during meatball storage. Their antioxidant effect depended on flax variety (brown or golden) and preparation type (DFM or AFE). Lower level of PV and TBARS, compared with the ones with AFE, were noted in meatballs with DFM. Both DFM and AFE, from the brown seed variety, protect the lipids against oxidation to a higher extent. During the storage, a cholesterol degradation was observed. AFE (particularly from the brown variety) limited changes in cholesterol content. Moreover, they stabilized fatty acid composition of stored meatballs. However, DFM efficiently inhibited cholesterol oxidation.

In recent years, cholesterol oxidation products (COPs) have drawn scientific interest, particularly due to their implications on human health. A big number of these compounds have been demonstrated to be cytotoxic, mutagenic, and carcinogenic. The main source of COPs is through diet, and particularly from the consumption of cholesterol-rich foods. This raises questions about the safety of consumers, and it suggests the necessity for the development of a sensitive and a reliable analytical method in order to identify and quantify these components in food samples. Sample preparation is a necessary step in the analysis of COPs in order to eliminate interferences and increase sensitivity. Numerous publications have, over the years, reported the use of different methods for the extraction and purification of COPs. However, no method has, so far, been established as a routine method for the analysis of COPs in foods. Therefore, it was considered important to overview different sample preparation procedures and evaluate the different preparative parameters, such as time of saponification, the type of organic solvents for fat extraction, the stationary phase in solid phase extraction, etc., according to recovery, precision and simplicity. © 2013 Elsevier Ltd. All rights reserved. 145 918 926 Cited By :11

The intake of fruits and vegetables is associated with reduced incidence of many chronic diseases. These foods contain phytochemicals that often possess antioxidant and free radical scavenging capacity and show anti-inflammatory action, which are also the basis of other bioactivities and health benefits, such as anticancer, anti-aging, and protective action for cardiovascular diseases, diabetes mellitus, obesity and neurodegenerative disorders. Many factors can be included in the etiopathogenesis of all of these multifactorial diseases that involve oxidative stress, inflammation and/or cell death processes, oxysterols, i.e. cholesterol oxidation products (COPs) as well as phytosterol oxidation products (POPs), among others. These oxidized lipids result from either spontaneous and/or enzymatic oxidation of cholesterol/phytosterols on the steroid nucleus or on the side chain and their critical roles in the pathophysiology of the abovementioned diseases has become increasingly evident. In this context, many studies investigated the potential of dietary phytochemicals (polyphenols, carotenoids and vitamins C and E, among others) to protect against oxysterol toxicity in various cell models mimicking pathophysiological conditions. This review, summarizing the mechanisms involved in the chemopreventive effect of phytochemicals against the injury by oxysterols may constitute a step forward to consider the importance of preventive strategies on a nutritional point of view to decrease the burden of many age-related chronic diseases.

The aim of this paper was the quantification of cholesterol loss and of its oxidation products in fresh egg pasta submitted to different thermal treatments. COPs were analysed by LC-MS/MS. The results showed that the COP concentration increased with increasing heating severity (expressed as F 100/10 value) from 66.44 μg/g in the raw pasta up to 117.9 μg/g after 120 min at the reference temperature of 100 °C; under the same processing conditions, the cholesterol loss reached 75%. This study revealed that 7-ketocholesterol (7-keto) is the main COP found and showed a linear correlation between its concentration and (i) total COP amount (r2 = 0.981; p < 0.05), (ii) TBARS value (r2 = 0.969; p < 0.05) and (iii) heating time expressed as a logarithm of F 100/10 value (r2 = 0.999 e p < 0.01). The total amount of COPs found in the product was very low when compared to literature values reported for dried egg pasta and did not exceed 0.32 mg/kg.

Cholesterol oxidation products (COPs) are a group of compounds formedduring processing and storage of foods from animal origin. After ingestion,COPs are absorbed in the intestine and can be distributed to serum andvarious tissues, potentially promoting a variety of toxic effects. Therefore,inhibition of their intestinal absorption may contribute to reduce the healthrisks associated with dietary intake of COPs. Some studies have shown thatdrugs and dietary compounds may inhibit the intestinal absorption of dietaryCOPs. However, proven cholesterol- and/or food toxins-binding lactic acidbacteria have not been previously evaluated as potential COPs removal agents.The aim of this study was to assess the ability of Lactobacillus casei ATCC334to remove COPs in aqueous solution. Results showed the ability of bothgrowing and resting cells to remove COPs (ca. 30-60%). All COPs–bacteriuminteractions were specific and partly reversible, being resting cells the mostefficient for COPs removal in a ranking order of 7-KC > 7a-OH/7b-OH > triol > 5,6b-EP > 5,6a-EP > 25-OH. Binding to the cell wall and/or cellmembrane incorporation appears to be the most likely mechanisms involvedon COPs removal by L. casei ATCC 334.IntroductionCholesterol is a molecule with an unsaturated bond atposition D5-6 of the sterol nucleus, which makes it proneto oxidation. Cholesterol oxidation products (COPs) are aheterogeneous group of molecules with additional oxygensubstitutions, such as hydroxy, carbonyl, epoxy orhydroperoxy groups on the cholesterol nucleus and/or ahydroxy one in the sterol side chain (Olkkonen andHynynen 2009). COPs can be generated in the humanorganism through different oxidation processes (i.e. lipo-protein oxidation at the blood stream and/or at the intra-cellular metabolism) or via enzymatic catalysis bycholesterol oxidase from human gut bacteria (Valenzuelaet al. 2003; Aparicio and Martin 2008; Otaegui-Arrazolaet al. 2010). Furthermore, COPs can be formed in choles-terol-containing foods (e.g. egg, whole milk, meats, sea-food) during food production, processing, distribution

We make a bibliographical review on the main aspects related to the cholesterol oxidation products, including their biological effects, their presence and formation in food and their analytical determination. Se realiza una revisión bibliográfica de los aspectos nutricionales y bromatológicos de los llamados oxiesteroles. Se recogen los efectos biológicos descritos para estos compuestos, su presencia y formación en alimentos y la metodología analítica para su determinación.

We make a bibliographical review on the main aspects related to the cholesterol oxidation products, including their biological effects, their presence and formation in food and their analytical determination.Se realiza una revisión bibliográfica de los aspectos nutricionales y bromatológicos de los llamados oxiesteroles. Se recogen los efectos biológicos descritos para estos compuestos, su presencia y formación en alimentos y la metodología analítica para su determinación.