History of Cholesterol Autoxidation

Smith, Leland L.

doi:10.1007/978-1-4757-9691-9_2

Cited by 100 publications

(177 citation statements)

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“…The product was purified by dialysis (against MilliQ water) in the dark for 3 days. In line with previous detection studies, 72 UV-Vis investigations of P(MAA-co-CMA) copolymers revealed a distinctive peak at 275 nm, which enhanced with increasing CMA moieties, evidencing the short wavelength to be specific to cholesterol units in the composition. Accordingly the fluo-rescent dye content of 8 mol% CMA was quantified by UV-Vis spectrometer analysis, where a calibration curve was built from standard solutions of 8 mol% CMA in MilliQ water at 275 nm ( Fig.…”

Section: Methodssupporting

confidence: 90%

The endocytic pathway and therapeutic efficiency of doxorubicin conjugated cholesterol-derived polymers

et al. 2015

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Previously synthesized poly(methacrylic acid-co-cholesteryl methacrylate) P(MAA-co-CMA) copolymers were examined as potential drug delivery vehicles. P(MAA-co-CMA) copolymers were fluorescently labelled and imaged in SHEP and HepG2 cells. To understand their cell internalization pathway endocytic inhibition studies were conducted. It was concluded that P(MAA-co-CMA) are taken up by the cells via clathrin-independent endocytosis (CIE) (both caveolae mediated and cholesterol dependent endocytosis) mechanisms. The formation and characterization of P(MAA-co-CMA)-doxorubicin (DOX) nanocomplexes was investigated by fluorescence lifetime imaging microscopy (FLIM), UV-Visible spectroscopy (UV-Vis) and dynamic light scattering (DLS) studies. The toxicity screening between P(MAA-co-CMA)-DOX nanocomplexes (at varying w/w ratios) and free DOX, revealed nanocomplexes to exhibit higher cytotoxicity towards cancer cells in comparison to normal cells. FLIM and confocal microscopy were employed for investigating the time-dependent release of DOX in SHEP cells and the cellular uptake profile of P(MAAco-CMA)-DOX nanocomplexes in cancer and normal cell lines, respectively. The endocytic pathway of P(MAA-co-CMA)-DOX nanocomplexes were examined in SHEP and HepG2 cells via flow cytometry revealing the complexes to be internalized through both clathrin-dependent (CDE) and CIE mechanisms. The drug delivery profile, reported herein, illuminates the specific endocytic route and therapeutic efficiency of P(MAA-co-CMA)-DOX nanocomplexes strongly suggesting these particles to be promising candidates for in vivo applications.

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Section: Methodssupporting

confidence: 90%

The endocytic pathway and therapeutic efficiency of doxorubicin conjugated cholesterol-derived polymers

et al. 2015

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“…Employing an internal calibration using known DHB and cholesterol fragmentation peaks, the accurate masses of the radical cation peaks were determined. [12] and Uemi et al [11] led to the deduction that solution oxidation products contain hydroperoxide structures (Scheme 1c and d). However, there is no source of molecular oxygen or peroxide in either the matrix or analyte when under the vacuum conditions of the mass spectrometer.…”

Section: Identification and Origin Of Oxidation Productsmentioning

confidence: 99%

“…Van der Brink et al [31] were also able to see a peak at m/z 382 which indicates possible protonation occurring at the hydroxyl group of the 399 Da neutral molecule in Scheme 2 (top row, right column) followed by water loss. In our laboratory, the known cholesterol oxidation products 5-cholestene-3β,7β-diol, 5-cholesten-3β-ol-7-one, and cholesterol 5β,6β-epoxide [12,31] were purchased commercially and were then run on the MALDI-TOF instrument to test whether radical oxidation products would be generated from these compounds. The three known oxidation products were dissolved in CHCl 3 :CH 3 OH and mass spectra were acquired under conditions similar to those used for cholesterol.…”

Section: Comparison To Known Oxidation Productsmentioning

confidence: 99%

“…The oxygen-mediated and radical-mediated oxidation pathways of cholesterol have been studied extensively [10][11][12]. Smith [12] has shown that oxidation of cholesterol via the excited singlet state molecular oxygen pathway implicates 3β-hydroxy-5α-cholest-6-ene-5-hydroperoxide and 7α-hydroperoxide, whereas oxidation via the free radical mechanism involves 7-peroxy radicals or 7-hydroperoxides.…”

Section: Introductionmentioning

confidence: 99%

“…There are over 70 known oxidation products of cholesterol; this fact serves as evidence of the complexity of cholesterol oxidation [12]. Many oxidation products of cholesterol have been studied by GC-MS [13,14], EI-MS [15], SIMS [16], and HPLC [17,18].…”

Section: Introductionmentioning

confidence: 99%

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Laser-Induced Oxidation of Cholesterol Observed During MALDI-TOF Mass Spectrometry

McAvey

Guan

Fortier

et al. 2011

J. Am. Soc. Mass Spectrom.

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Conditions for the detection of three odd-electron cholesterol oxidation peaks were determined and these peaks were shown to be artifacts of the matrix-assisted laser desorption time of flight (MALDI-TOF) process. Matrix choice, solvent, laser intensity and cholesterol concentration were systematically varied to characterize the conditions leading to the highest signals of the radical cation peaks, and it was found that initial cholesterol solution concentration and resultant density of solid cholesterol on the MALDI target were important parameters in determining signal intensities. It is proposed that hydroxyl radicals, generated as a result of laser irradiation of the employed 2, 5-dihydroxybenzoic acid (DHB) matrix, initiate cholesterol oxidation on the MALDI target. An attempt to induce the odd-electron oxidation peaks by means of adding an oxidizing agent succeeded using an acetonitrile solution of DHB, cholesterol, and cumene hydroperoxide. Moreover, addition of free radical scavengers reduced the abundances of some oxidation products under certain conditions. These results are consistent with the mechanism of oxidation proposed herein involving laser-induced hydroxyl radical production followed by attack on neutral cholesterol. Hydroxyl radical production upon irradiation of dithranol matrix may also be responsible for generation of the same radical peaks observed from cholesterol in dithranol by an analogous mechanism.

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Stability of Cholesterol and Paprika Carotenoids in Egg Powders as Influenced by Dietary and Processing Treatments

Lai

Gray

Partridge

et al. 1996

J. Sci. Food Agric.

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The effects of dietary a-tocopherol and/or oleoresin paprika (OP) on cholesterol and carotenoid stability in egg powders during spray drying and subsequent storage were investigated. Cholesterol oxidation and loss of carotenoids in eggs dried with a direct gas-fired spray dryer were greater (P < 0.05) than in eggs dried using an indirect (electric) heating system. Dietary supplementation of a-tocopherol acetate (200 mg kg-feed) significantly increased (P < 0.01) the oxidative stability of cholesterol and carotenoids in eggs dried with the direct heating system. Supplementation of O P (7.5 pg g-' egg lipids) through diet or by direct addition to liquid eggs did not affect the formation of cholesterol oxidation products (COPS) during storage. However, increased concentrations of OP in liquid eggs (15 and 30 pg g-' lipids) suppressed the formation of COPS during processing and subsequent storage.

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History of Cholesterol Autoxidation

Cited by 100 publications

References 0 publications

The endocytic pathway and therapeutic efficiency of doxorubicin conjugated cholesterol-derived polymers

The endocytic pathway and therapeutic efficiency of doxorubicin conjugated cholesterol-derived polymers

Laser-Induced Oxidation of Cholesterol Observed During MALDI-TOF Mass Spectrometry

Stability of Cholesterol and Paprika Carotenoids in Egg Powders as Influenced by Dietary and Processing Treatments

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