Biological effects of oxysterols: current status.
ABSTRACT A review of relevant literature on biological activities of oxysterols (OS) and cholesterol is presented. The data clearly demonstrate manifold biological activities, often detrimental, for OS compared with little or no such activity of a deleterious nature for cholesterol itself. Cholesterol is perhaps the single most important compound in animal tissue and, as such, it is difficult to imagine it as a toxin or hazard. In contrast, OS exhibit cytotoxicity to a wide variety of cells leading to angiotoxic and atherogenic effects; alter vascular permeability to albumin; alter prostaglandin synthesis and stimulate platelet aggregation, an important process facilitating atherosclerosis and thrombosis; alter the functionality of low density lipoprotein (LDL) receptors, possibly stimulating hypercholesterolaemia; modify cholesteryl ester accumulation in various cells, inducing foam cell formation; and enrich the LDL particle in cholesteryl esters, possibly increasing its atherogenicity. Furthermore, OS are mutagenic and carcinogenic, although some have been studied as antitumour agents based on their cytotoxic properties. Moreover, numerous studies have implicated OS in membrane and enzyme alterations that are interrelated with many of the foregoing effects. The authors find that OS deserve much more attention than cholesterol itself in terms of research activity but that unfortunately the reverse is true with regard to funding.
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ABSTRACT: BACKGROUND: Rice is the staple food and one of the world's three major grain crops. Rice contains more than 100 bioactive substances including phytic acid, isovitexin, ¿-oryzanol, phytosterols, octacosanol, squalene, ¿-aminobutyric acid (GABA), tocopherol, tocotrienol derivatives, etc. Out of them, ¿-oryzanol is known to have important biological profile such as anti-oxidants, inhibitor of cholesterol oxidation, reduce serum cholesterol levels in animals, effective in the treatment of inflammatory diseases, inhibit tumor growth, reduce blood pressure and promotes food storage stability when used as a food additive, etc. Hence in the present investigation, we aimed to evaluate the content and composition of ¿-oryzanol from pigmented rice germplasms using a liquid chromatography with diode array detection and electrospray ionization-mass spectrometry (LC-DAD-ESI/MS). FINDINGS: In the present study, 33 exotic pigmented rice accessions (red, white and purple) have been evaluated. Among them, the contents of ¿-oryzanol varied from 3.5 to 21.0 mg/100 g with a mean of 11.2 mg/100 g. A total of ten components of ¿-oryzanol including ¿7-stigmastenyl ferulate were identified of which, cycloartenyl ferulate, 24-methylenecycloartanyl ferulate, campesteryl ferulate and sitosteryl ferulate were identified as the major components. The mean proportions of steryl ferulates were in the descending order of 24-methylenecycloartanyl ferulate > cycloartenyl ferulate > campesteryl ferulate > sitosteryl ferulate > ¿7-campestenyl ferulate > campestanyl ferulate > sitostanyl ferulate > ¿7-stigmastenyl ferulate > stigamsteryl ferulate > ¿7-sitostenyl ferulate. Almost 11 accessions (33%) showed higher content than the control rice Chucheongbyeo and higher proportions ranged from 10 to 15 mg/100 g. Interestingly, the red rice accession Liberian Coll. B11/B-11 (21.0 mg/100 g) showed higher content ¿-oryzanol than control rice Jeokjinjubyeo (19.1 mg/100 g) and the purple rice accession Padi Adong Dumarat, Mardi No.4376 (20.3 mg/100 g) showed a similar content with control rice Heugjinjubyeo (21.4 mg/100 g). CONCLUSIONS: Most of analyzed rice accessions were found to possess higher contents of ¿-oryzanol than the control rice, Chucheongbyeo. In particular, the red accessions showed highest content than the white and purple accessions. The content and composition of ¿-oryzanol in 33 exotic pigmented rice accessions have been evaluated and compared significantly by the present investigation.BMC Research Notes 04/2013; 6(1):149.
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ABSTRACT: Human atherosclerotic plaque is composed of a large mixture of elements, predominantly lipids and oxidized lipids, lipid-loaded macrophages and smooth muscle cells, forming foam cells. Plaque contents undergo dynamic changes during the plaque's progression, being in a constant interaction with the circulating blood. During the mutual interaction between blood and plaque and the specific biochemical processes occurring in both, specific molecules can be generated in the serum which might provide information on plaque status. This information, mostly on plaque vulnerability, is highly important for making appropriate treatment decisions before neurological symptoms appear. The present review summarizes plaque contents, mostly lipids, oxidized lipids, oxidized products of cholesterol (oxysterols), and covers the recent literature on their association with biomarkers in the blood and on the possibility of using them for providing information on plaque status.Biochemical pharmacology 02/2013; · 4.25 Impact Factor
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ABSTRACT: Atherosclerosis is the most common cause of mortality in the Western world, contributing to about 50% of all deaths. Atherosclerosis is characterized by deposition of lipids onto the coronary or carotid arterial wall and formation of an atherosclerotic plaque. Atherosclerotic plaques are categorized into two groups: symptomatic and asymptomatic. The symptomatic plaques tend to be unstable and prone to rupture, and are associated with an increase in ischemic events.Oxysterols, products of cholesterol oxidation,are cytotoxic materials. Their level and type may be associated with plaque formation, development and stability. Oxysterolsstimulate the formation of foam cells, advance atherosclerotic plaque progression, and contribute to plaque vulnerability and instability due to their cytotoxicity and their ability to induce cell apoptosis. Studies indicate that plasma 7β-OH CH level can be used as a biomarker for detecting carotid and coronary artery disease. Further clinical studies are needed to evaluate the potential of oxysterols for use as biomarkers for plaque vulnerability and instability. The identification of biomarkers in the blood that can distinguish between symptomatic and asymptomatic plaques remains an unresolved issue.Biochemical and Biophysical Research Communications 01/2014; · 2.41 Impact Factor