Topic
Sterol
About: Sterol is a research topic. Over the lifetime, 8117 publications have been published within this topic receiving 309926 citations. The topic is also known as: sterols & sterol lipids.
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TL;DR: Oils extracted from Tunisian and Iranian Nigella seeds (TNS and INS, respectively) and Tunisian Aleppo pine seeds were analyzed for sterol composition in this paper, and the highest level of total unsaponifiable matter was found in Pinus seed oil.
111 citations
TL;DR: The results support the suggestion that sterols in plant cells may have a physiological function associated with membranes, and the intracellular distribution pattern of cholesterol-(14)C added to the isolation medium provided evidence that the intrACEllular sterol distribution pattern is not an artifact.
Abstract: All membrane-containing fractions isolated from tobacco leaves contained free sterols, sterol glycosides, and sterol esters. The three sterol forms increased, on a dry weight basis, with a decrease in particle size. The supernatant fraction contained only trace amounts of sterol. The major sterols in all cellular fractions, in the order of decreasing amounts, were: stigmasterol, beta-sitosterol, campesterol, and cholesterol. The 500g pellet contained the largest percentage of free sterol, while the 46,000g pellet contained the largest percentage of esterified sterol. The individual sterol composition of the free sterol and sterol glycoside fraction was very similar; however, the composition of the sterol ester fraction varied widely among intracellular fraction. The intracellular distribution pattern of cholesterol-(14)C added to the isolation medium provided evidence that the intracellular sterol distribution pattern is not an artifact. These results support the suggestion that sterols in plant cells may have a physiological function associated with membranes.
111 citations
TL;DR: Calculations based on a two-pool model show that the plasma ratio method should be applicable to studies in man, and would allow calculation of dietary cholesterol absorption and endogenous cholesterol synthesis from plasma cholesterol specific activity data.
Abstract: SummaryThe determination of cholesterol absorption in rats from a single blood sample is described. The method consists of dosing the rats with a collodial suspension of cholesterol-3H intravenously and with cholesterol-14C orally. The ratio of 14C to3H in plasma, 24 hr or more after isotope dosage, gives the fraction of the oral dose absorbed. The method was tested by comparison to fecal 14C-cholesterol excretion corrected for recirculated sterol and sterol degradation. The results of the two methods are in good agreement. Calculations based on a two-pool model show that the plasma ratio method should be applicable to studies in man, and would allow calculation of dietary cholesterol absorption and endogenous cholesterol synthesis from plasma cholesterol specific activity data.The excellent technical assistance of L. Barry Hughes is appreciated.
110 citations
TL;DR: The present results suggest that the sterol 27-hydroxylase in the lung is responsible for at least half of the total flux of 27-oxygenated cholesterol metabolites to the liver and that this enzyme system may be of importance for cholesterol homeostasis in the lungs.
110 citations
TL;DR: The unsaponifiables from threeTheaceae oils and alfalfa, garden balsam, and spinach seed oils and shea fat were separated into four fractions: sterols, 4-methylsterols, triterpene alcohols, and less polar compounds by thin layer chromatography.
Abstract: The unsaponifiables from threeTheaceae (Camellia japonica L.,Camellia Sasanqua Thunb., andThea sinensis L.) oils and alfalfa, garden balsam, and spinach seed oils and shea fat were separated into four fractions: sterols, 4-methylsterols, triterpene alcohols, and less polar compounds by thin layer chromatography. While the sterol fraction was the major one for the unsaponifiables from alfalfa and spinach seed oils, the triterpene alcohol fraction was predominant for the unsaponifiables from all other oils. The sterol, 4-methylsterol, and triterpene alcohol fractions were analyzed by gas chromatography. All the sterol fractions were alike in their compositions, consisting exclusively of Δ7-sterols, such as α-spinasterol and Δ7-stigmastenol as predominant components together with Δ7-avenasterol and 24-methylcholest-7-enol. Obtusifoliol, gramisterol (occasionally accompanied with cycloeucalenol), and citrostadienol, together with several other unidentified components, were found in the 4-methylsterol fractions from all of the oils except shea fat. The 4-methylsterol fraction from shea fat showed a characteristic composition containing a large proportion of unidentified components which had relative retention time greater than that of citrostadienol, while no citrostadienol was detected. β-Amyrin, lupeol, and butyospermol were major components of the triterpene alcohol fractions from most of the oils, but the fraction from spinach seed oil contained cycloartenol and 24-methylene-cycloartanol as predominant components. There is a close similarity in the compositions of unsaponifiables (sterols, 4-methylsterols, and triterpene alcohols) of the threeTheaceae oils. Two sterols, α-spinasterol and Δ7-stigmastenol, and five triterpene alcohols were isolated from tea seed oil. Moreover, five unidentified components beside parkeol, butyrospermol, α-amyrin, and lupeol were isolated from the triterpene alcohol fraction of shea fat.
110 citations