Cholesterol oleate

Powdered cholesterol oleate la (3.00 g, 4.6 mmol) was evacuated in a 500 mL flask and cooled to -30 °C. HBr gas (1 bar, 22 mmol) was let in. After 10 h, excess gas was pumped off and condensed in a cold trap for further use. The quantitatively obtained crystals 2a were collected in pure form. 

A Phase I clinical study was carried out in four ovarian cancer patients to exploit the drug targeting ability of cholesterol-rich emulsions to LDL receptors of tumor cells. UptakiHjf [ etoposide oleate and fc] cholesterol oleate were 4.1 times and 4.9 times, respectively, greater than that in contralateral normal ovaries. This indicates that most ofthe etoposide is retained in the emulsion before its internalization by the tumor cells and shows the ability of ofthe cholesterol-rich emulsions to concentrate in ovarian carcinomas (Azevedo et al., 2005). 

ApoE mice Human femoral arteries Atherosclerosis MSI Mouse and human Phosphatidylcholine Cholesteryl linoleate Cholesterol oleate Human triacylglycerol (29)... 

Using MALDI-MSI-based histopathologic examination, Zaima et al. (29) identified and visualized specific markers for aortic atherosclerosis lesions in mice ApoE and in human. They found the same distribution in mice and human samples, in several molecules cholesterol linolate, cholesterol oleate, and phosphatidylcholine. The triacylglycerol only appeared in human... 

Cholesterol esters form crystalline structures that are similar to those formed by other lipids, consisting of alternating infinite lamellae, so that the hydrocarbon chains form close-packed sheets segregated from layers of cholesterol skeletons. There are three t) s of such structures [6]. One such can be represented by the chiral molecule cholesterol oleate, where pairs of cholesterol skeletons are arranged in an antiparallel packing in one layer, with the hydrocarbon chains in the adjacent layer. The cross-sectional area of the cholesterol molecule is about 40 A2 (derived from pressure-area monolayer curves), corresponding to the cross-sectional area of two hydrocarbon chains. The chains therefore form an interpenetrating layer. 

Results. Similar absorbances are found for triolein, cholesterol oleate, dipalmitoyl lecithin, and dipalmitoyl cephalin. Sphingomyelin, which has an amide fatty acid linkage, does not undergo hydroxylaminolysis. The standard error of the method is 0.36 mEq for an acyl ester concentration of 7-20 mEq/liter serum. 

Soluble substrates are available which are cleaved by carboxylester lipase in the absence of bile salts, such as the not quite specific para-nitrophenylacetate [40] or the dilaurate ester of fluorescein [51,52] (Fig. 9). However, bile salts not only protect the enzyme, but interact specifically with the enzyme, affecting approximately 7- to 10-fold the activity on water-soluble substrates like para-nitrophenylacetate. When water-insoluble esters like triolein or cholesterol oleate are selected as the substrate, the enzyme is virtually inactive without bile salts, which gives them the character of essential activators [53]. In contrast to pancreatic lipase, carboxylester lipase needs no cofactor like colipase and is not activated by an oilAvater interface. Purified carboxylester lipase loses the majority of its activity by lyophylization but can be stored frozen at -20°C [46]. 

The properties of the phospholipase activities from cultures of P. infestans (4) are summarized in Table III. Of the five types of liquid media tested, the greatest phospholipase activity was obtained when P. infestans was grown in rye steep media. The phospholipase activity in rye culture filtrates was stimulated 15-fold by omitting glucose from the medium. The addition of 100 mg/liter of phosphatidylcholine (PC) to the rye medium caused an additional 35-fold stimulation in the activity of phospholipase. These experiments suggest that this enzyme activity is inducible. The addition of other lipids (sunflower oil, wax ester, and cholesterol oleate) to rye media also caused an apparent induction of phospholipase activity. We also detected extracellular phospholipase activity in lima bean agar cultures of P. infestans as shown in the second column of Table III. When the fungus was collected... 

It has been reported that oleic acid is most readily esterified with cholesterol during its absorption (35, 34). Furthermore, Swell and Treadwell (34) also reported that the cholesterol ester which accumulated to the greatest extent, irrespective of the fatty acid fed, was cholesterol oleate. Thus, the endogenous cholesterol esters may be rich in oleic acid. 

Figure 5 The effect of the nature of the emulsifier on the phagocytosis of fat emulsions by mouse peritonea] macrophages. PC (phosphatidylcholine), PE

Fig. 1. Calorimeter heating scans of various lipidsr Stearic acid. (B) Cholesterol oleate. (C) A calcium precipitate of cardiolipin.

In an excellent study of neutral lipids by Foglia and Jones [836], a 100/0/0.4 (hold 5 min) -> 20/80/0.4 (at 15 min hold 2 min) hexane/MrBE/acetic acid gradient was used with a cyanopropyl column (ELSD, 40°C drift tube, and = 1.5 L/min). Two separations are shown, one involving neutral lipid standards (cholesterol, oleate, methyl oleate, oleic acid, triolein, 1,3- and 1,2-diolein, 1- and 2-monoolein) and the other IPA-transesterifled tallow separated into fractions (isopropylesters, free fatty acids, triglycerides, 1,3- and 1,2-diglycerides, and 1-monoglyceride). Area vs. concentration plots for these analytes were nonlinear over the 0-50 pg/mL range. Overall separations were excellent, as were peak shapes. 

Fig. 1.- Thin layer chromatography of esterified cholesterol. Cholesterol esters were purified according to Horning et al. (I960) and run on TLC with heptane-ethyl ether (24 1). Spots were visualized with Liebermann-Bouchard reagent. Cholesterol oleate standard (St). Material from animals injected with Freund s adjuvant (FC) white matter (WM)j myelin (My) apoprotein of Folch s proteolipid (AFP) basic protein (BP) basic protein plus CNS lipids (BPL).

The sterides are esters of fatty acids and sterols. Lanoline, the fat obtained from wool, is a mixture of cholesterol oleate, palmitate, and stearate. 

In Table 1 is shown the effect of ATP concentration on the reactivation of microsomal ACAT by a partially purified microsomal protein kinase. This data illustrates that cholesterol oleate formation increases with an increase in the amount of ATP added. In Fig. k is shown the reversible modulation of ACAT activity where dephosphorylating conditions bring about a decrease in the enzyme activity, which is reactivated in the presence of ATP and protein kinase. These data, taken together, illustrate (Fig. 5) that ACAT is active when phosphorylated— that is, in the presence of protein kinase and ATP—while it is inactive when it is dephosphorylated or in the presence of protein phosphatase and magnesium. 

Chem. Descrip. Cholesterol oleate CAS 303-43-5 EINECS/ELINCS 206-142-1 Uses Surfactant suitable for use In pharmaceuticals, etc. 

A number of enhancers has been shown to alter skin structure. Kaplun-Frischoff and Touitou [182] used DSC to show that menthol decreased the melting point of cholesterol oleate and ceramides and modified the DSC scan of isolated stratum corneum. This partly accounted for an eight-fold enhancement of the skin flux of testosterone. 

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