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Journal of Lipid Research Jun 1993The continuous isotope feeding method of Crouse and Grundy (1978. J. Lipid Res. 19: 967-971) for measurement of dietary cholesterol absorption has been modified by using...
The continuous isotope feeding method of Crouse and Grundy (1978. J. Lipid Res. 19: 967-971) for measurement of dietary cholesterol absorption has been modified by using markers labeled with stable isotopes ([2,2,4,4,6-2H5]cholesterol or [25,26,26,26,27,27,27-2H4]cholesterol or [26,26,26,27,27,27-2H6] cholesterol and [5,6,22,23-2H4]sitostanol) quantified by gas-liquid chromatography-selected ion monitoring. Tracing of the isotope distribution of the authentic markers and after their intestinal passage, including the microbiological products (coprostanol and coprostanone) revealed stability of the labels. The new method was evaluated in six monkeys on two occasions by comparison with the original method using radioactively labeled cholesterol and sitosterol. The results obtained by the two different methods were in excellent agreement, and absorption ranged from 49% to 73% (mean 60%) for the stable isotope method and from 51% to 69% (mean 62%) for the radioactive method. The coefficient of variation of cholesterol absorption in animals ranged from 3.9% to 15.1% (mean 7.1%) for stable isotopes and 1.9% to 13.6% (mean 5.7%) for radioactive isotopes. In twelve subjects cholesterol absorption was measured by the new method from total fecal samples frozen immediately and compared to results obtained from small fecal aliquots (approximately 1 g) sent by ordinary mail to the laboratory. A significant correlation of cholesterol absorption between the two different sample handlings was obtained (r = 0.981, P < 0.001). In addition, measurement of cholesterol absorption twice in seven volunteers 2 weeks apart revealed identical results. Thus, the new method is extremely safe and reproducible without radioactive exposure to the subjects and labortory staff and can be used on women of child-bearing age.
Topics: Animals; Cholesterol; Cryopreservation; Deuterium; Feces; Gas Chromatography-Mass Spectrometry; Humans; Hypercholesterolemia; Intestinal Absorption; Macaca fascicularis; Male; Sitosterols
PubMed: 8354951
DOI: No ID Found -
Journal of Clinical Pathology Nov 2002To assess the specificity and sensitivity of the commonly used enzymatic colorimetric test for plasma cholesterol determination.
AIM
To assess the specificity and sensitivity of the commonly used enzymatic colorimetric test for plasma cholesterol determination.
METHODS
Interference with an enzymatic method for cholesterol measurement by several non-cholesterol sterols (beta sitosterol, campesterol, stigmasterol, stigmastanol, desmosterol, and lathosterol) was assessed. Some of these compounds are present in plasma at higher than normal concentrations either in rare genetic disorders, such as phytosterolaemia, or after the consumption of phytosterol enriched foods.
RESULTS
The non-cholesterol sterols were detected by the assay in a linear manner. There was no competitive interference in the presence of cholesterol.
CONCLUSIONS
This crossreactivity may affect the diagnosis and treatment of non-cholesterol dyslipidaemias, including phytosterolaemia and cerebrotendinous xanthomatosis. Similarly, changes in plasma lipid compositions after the consumption of phytosterol enriched foods cannot be specifically determined by this enzymatic assay. Until a more specific enzymatic assay is developed, alternative methods such as gas chromatography should be used to differentiate between cholesterol and non-cholesterol sterols.
Topics: Cholesterol; Colorimetry; Cross Reactions; Humans; Hyperlipidemias; Phytosterols; Sensitivity and Specificity; Sterols
PubMed: 12401826
DOI: 10.1136/jcp.55.11.859 -
Foods (Basel, Switzerland) May 2020Fresh pasta was formulated by replacing wheat semolina with 0, 5, 10, and 15 g/100 g () of L. leaf powder (MOLP). The samples (i.e., M0, M5, M10, and M15 as a function...
Fresh pasta was formulated by replacing wheat semolina with 0, 5, 10, and 15 g/100 g () of L. leaf powder (MOLP). The samples (i.e., M0, M5, M10, and M15 as a function of the substitution level) were cooked by boiling. The changes in the phenolic bioaccessibility and the in vitro starch digestibility were considered. On the cooked-to-optimum samples, by means of ultra-high-performance liquid chromatography-quadrupole time-of-flight (UHPLC-QTOF) mass spectrometry, 152 polyphenols were putatively annotated with the greatest content recorded for M15 pasta, being 2.19 mg/g dry matter ( < 0.05). Multivariate statistics showed that stigmastanol ferulate (VIP score = 1.22) followed by isomeric forms of kaempferol (VIP scores = 1.19) and other phenolic acids (i.e., schottenol/sitosterol ferulate and 24-methylcholestanol ferulate) were the most affected compounds through the in vitro static digestion process. The inclusion of different levels of MOLP in the recipe increased the slowly digestible starch fractions and decreased the rapidly digestible starch fractions and the starch hydrolysis index of the cooked-to-optimum samples. The present results showed that MOLP could be considered a promising ingredient in fresh pasta formulation.
PubMed: 32422925
DOI: 10.3390/foods9050628 -
Journal of Lipid Research Jul 1970By vapor-programmed thin-layer chromatography on silica gel, it was possible to separate cholestanol from cholesterol and stigmastanol from beta-sitosterol. The method...
By vapor-programmed thin-layer chromatography on silica gel, it was possible to separate cholestanol from cholesterol and stigmastanol from beta-sitosterol. The method was applied for the analysis of beta-sitosterol-3-(14)C.
Topics: Carbon Isotopes; Cholesterol; Chromatography, Thin Layer; Methods; Sterols
PubMed: 5459667
DOI: No ID Found -
BioMed Research International 2019L. (Rubiaceae) is a climber which is widely distributed in Asian countries including Malaysia. The plant is traditionally used to treat various diseases including...
L. (Rubiaceae) is a climber which is widely distributed in Asian countries including Malaysia. The plant is traditionally used to treat various diseases including diabetes. This study is to evaluate the enzymatic inhibition activity of twigs extracts and to identify the metabolites responsible for the bioactivity by gas chromatography-mass spectrometry (GC-MS) metabolomics profiling. Three different twig extracts, namely, hexane (PFH), chloroform (PFC), and methanol (PFM), were submerged for their -amylase and -glucosidase inhibition potential in 5 replicates for each. Results obtained from the loading column scatter plot of orthogonal partial least square (OPLS) model revealed the presence of 12 bioactive compounds, namely, dl--tocopherol, n-hexadecanoic acid, 2-hexyl-1-decanol, stigmastanol, 2-nonadecanone, cholest-8(14)-en-3-ol, 4,4-dimethyl-, (3,5)-, stigmast-4-en-3-one, stigmasterol, 1-ethyl-1-tetradecyloxy-1-silacyclohexane, ɣ-sitosterol, stigmast-7-en-3-ol, (3,5,24S)-, and -monostearin. molecular docking was carried out using the crystal structure -amylase (PDB ID: 4W93) and -glucosidase (PDB ID: 3WY1). -Amylase-n-hexadecanoic acid exhibited the lowest binding energy of -2.28 kcal/mol with two hydrogen bonds residue, namely, LYS178 and TYR174, along with hydrophobic interactions involving PRO140, TRP134, SER132, ASP135, and LYS172. The binding interactions of -glucosidase-n-hexadecanoic acid complex ligand also showed the lowest binding energy among 5 major compounds with the energy value of -4.04 kcal/mol. The complex consists of one hydrogen bond interacting residue, ARG437, and hydrophobic interactions with ALA444, ASP141, GLN438, GLU432, GLY374, LEU373, LEU433, LYS352, PRO347, THR445, HIS348, and PRO351. The study provides informative data on the potential antidiabetic inhibitors identified in twigs, indicating the plant has the therapeutic effect properties to manage diabetes.
Topics: Data Analysis; Gas Chromatography-Mass Spectrometry; Hypoglycemic Agents; Inhibitory Concentration 50; Least-Squares Analysis; Metabolome; Metabolomics; Molecular Docking Simulation; Multivariate Analysis; Plant Extracts; Principal Component Analysis; Rubiaceae; alpha-Amylases; alpha-Glucosidases
PubMed: 31275982
DOI: 10.1155/2019/7603125 -
Biophysical Journal Oct 2006Pulsed field gradient (pfg)-NMR spectroscopy was utilized to determine lipid lateral diffusion coefficients in oriented bilayers composed of 25 mol % sterol and...
Pulsed field gradient (pfg)-NMR spectroscopy was utilized to determine lipid lateral diffusion coefficients in oriented bilayers composed of 25 mol % sterol and equimolar amounts of dioleoylphosphatidylcholine and sphingomyelin. The occurrence of two lipid diffusion coefficients in a bilayer was used as evidence of lateral phase separation into liquid ordered and liquid disordered domains. It was found that cholesterol, ergosterol, sitosterol, and lathosterol induced domains, whereas lanosterol, stigmasterol, and stigmastanol resided in homogeneous membranes in the temperature interval of 24-70 degrees C. Among the domain-forming sterols, differences in the upper miscibility temperature indicated that the stability of the liquid ordered phase could be modified by small changes in the sterol structure. The domain-forming capacity for the different sterols is discussed in terms of the ordering effect of the sterols on the lipids, and it is proposed that the driving force for the lateral phase separation is the reduced solubility of the unsaturated lipid in the highly ordered phase.
Topics: Lipid Bilayers; Magnetic Resonance Spectroscopy; Membrane Microdomains; Phase Transition; Phosphatidylcholines; Sphingomyelins; Sterols; Temperature
PubMed: 16829566
DOI: 10.1529/biophysj.106.085480 -
Journal of Lipid Research Mar 2003The recent identification of the aberrant transport proteins ABCG5 and ABCG8 resulting in sitosterolemia suggests that intestinal uptake of cholesterol is an unselective... (Comparative Study)
Comparative Study
The recent identification of the aberrant transport proteins ABCG5 and ABCG8 resulting in sitosterolemia suggests that intestinal uptake of cholesterol is an unselective process, and that discrimination between cholesterol and plant sterols takes place at the level of sterol efflux from the enterocyte. Although plant sterols are structurally very similar to cholesterol, differing only in their side chain length, they are absorbed from the intestine to a markedly lower extent. In order to further evaluate the process of discrimination, three different sterols (cholesterol, campesterol, sitosterol) and their corresponding 5 alpha-stanols (cholestanol, campestanol, sitostanol) were compared concerning their concentration in the proximal small intestine, in serum, and in bile after a single oral dose of deuterated compounds. The data obtained support the hypothesis that i) the uptake of sterols and stanols is an extremely rapid process, ii) discrimination probably takes place on the level of reverse transport back into the gut lumen, iii) plant stanols are taken up, but not absorbed to a measurable extent, and iv) the process of discrimination probably also exists at the level of biliary excretion. The range of structural alterations that decrease intestinal absorption and increase biliary excretion is: 1) campesterol, 2) cholestanol-sitosterol, and 3) campestanol-sitostanol.
Topics: Animals; Bile; Cholestanols; Cholesterol; Cholesterol, Dietary; Intestinal Absorption; Intestine, Small; Male; Mice; Phytosterols; Plant Extracts; Sitosterols
PubMed: 12562824
DOI: 10.1194/jlr.M200393-JLR200 -
Water Research Sep 2012Improving the microbiological quality of coastal and river waters relies on the development of reliable markers that are capable of determining sources of fecal...
Improving the microbiological quality of coastal and river waters relies on the development of reliable markers that are capable of determining sources of fecal pollution. Recently, a principal component analysis (PCA) method based on six stanol compounds (i.e. 5β-cholestan-3β-ol (coprostanol), 5β-cholestan-3α-ol (epicoprostanol), 24-methyl-5α-cholestan-3β-ol (campestanol), 24-ethyl-5α-cholestan-3β-ol (sitostanol), 24-ethyl-5β-cholestan-3β-ol (24-ethylcoprostanol) and 24-ethyl-5β-cholestan-3α-ol (24-ethylepicoprostanol)) was shown to be suitable for distinguishing between porcine and bovine feces. In this study, we tested if this PCA method, using the above six stanols, could be used as a tool in "Microbial Source Tracking (MST)" methods in water from areas of intensive agriculture where diffuse fecal contamination is often marked by the co-existence of human and animal sources. In particular, well-defined and stable clusters were found in PCA score plots clustering samples of "pure" human, bovine and porcine feces along with runoff and diluted waters in which the source of contamination is known. A good consistency was also observed between the source assignments made by the 6-stanol-based PCA method and the microbial markers for river waters contaminated by fecal matter of unknown origin. More generally, the tests conducted in this study argue for the addition of the PCA method based on six stanols in the MST toolbox to help identify fecal contamination sources. The data presented in this study show that this addition would improve the determination of fecal contamination sources when the contamination levels are low to moderate.
Topics: Animals; Cattle; Cholestanes; Cholestanol; Cholestanols; Feces; Fresh Water; Humans; Phytosterols; Principal Component Analysis; Rivers; Seawater; Sitosterols; Swine; Water Microbiology; Water Pollutants, Chemical
PubMed: 22673347
DOI: 10.1016/j.watres.2012.05.003 -
The Science of the Total Environment Dec 2012Organic compounds such as sterols and hormones have been detected in surface waters at ecologically relevant concentrations with sources including effluent discharged...
Organic compounds such as sterols and hormones have been detected in surface waters at ecologically relevant concentrations with sources including effluent discharged from publicly owned treatment works (POTWs) as well as leachate and runoff from land amended with municipal sludge (biosolids). Greater than 20% of regulated effluents discharged into U.S. surface waters experience in-stream dilution of <10-fold and potential impacts are particularly likely in receiving waters dominated by POTW effluents. The increasing use of biosolids on agricultural land exerts additional stress, thereby necessitating environmental monitoring for potential ecological and human health effects. Alternatively or in addition to monitoring efforts, screening for potentially hazardous chemicals can be performed using empirical models that are scalable and can deliver results rapidly. The present study makes use of data from U.S. EPA's Targeted National Sewage Sludge Survey (TNSSS) to predict the aqueous-phase concentrations and removal efficiencies of 10 sterols (campesterol, β-sitosterol, stigmasterol, β-stigmastanol, cholesterol, desmosterol, cholestanol, coprostanol, epicoprostanol, and ergosterol) as well as the putative toxicity posed by four specific hormones based on their reported biosolids concentrations using published empirical models. Model predictions indicate that removal efficiencies for sterols are uniformly high (~99%) and closely match removal rates calculated from chemical monitoring at POTWs (paired t-test; p=0.01). Results from toxicity modeling indicate that the hormones estrone, estradiol and estriol had the highest leaching potentials amongst the compounds considered here and that 17 β-ethinylestradiol was found to pose a potentially significant threat to fathead minnows (Pimephales promelas) via run-off or leaching from biosolids-amended fields. This study exemplifies the use of in silico analysis to (i) identify potentially problematic organic compounds in biosolids, (ii) predict influent and effluent levels for hydrophobic organic compounds (HOCs) of emerging concern, and (iii) provide initial estimates of runoff concentrations, in this case for four prominent hormones known to act as endocrine disruptors.
Topics: Animals; Endocrine Disruptors; Environmental Monitoring; Ethinyl Estradiol; Fishes; Hormones; Models, Theoretical; Risk Assessment; Rivers; Soil Pollutants; Sterols; Waste Disposal, Fluid; Water Pollutants, Chemical
PubMed: 22682556
DOI: 10.1016/j.scitotenv.2012.05.042 -
Arteriosclerosis, Thrombosis, and... Jul 2008We examined the effect of ezetimibe, a cholesterol absorption (CA) inhibitor, and genetic determinants of CA on reverse cholesterol transport (RCT) from subcutaneously...
OBJECTIVE
We examined the effect of ezetimibe, a cholesterol absorption (CA) inhibitor, and genetic determinants of CA on reverse cholesterol transport (RCT) from subcutaneously injected macrophages using a new dual isotope label technique.
METHODS AND RESULTS
Treatment of C57BL/6J mice with ezetimibe decreased dietary CA by 86% and increased RCT from peripheral tissue macrophages (PTM) by 6-fold (P<0.0001). Moreover, congenic 14DKK mice with a modest 41% decrease in dietary CA displayed a 67% increase in RCT from PTM (P<0.007).
CONCLUSIONS
These findings indicate that pharmacological and genetic modifiers of cholesterol absorption are major determinants of reverse cholesterol transport from peripheral tissue macrophages.
Topics: Animals; Anticholesteremic Agents; Azetidines; Cell Line; Cell Transplantation; Cholesterol, Dietary; Ezetimibe; Feces; Female; Intestinal Absorption; Intestines; Kinetics; Lipid Metabolism; Macrophages; Mice; Mice, Congenic; Mice, Inbred C57BL; Sitosterols
PubMed: 18420997
DOI: 10.1161/ATVBAHA.108.165803