Free Sterol Content Research Articles

Physiological and Biochemical Alterations during the Germination of Aspergillus Niger Conidia

The provided analytical data pertains to the germination of Aspergillus niger van Tieghem spores, focusing on various components measured by dry weight. These components include sugars, organic acids, amino acids, proteins, and lipids. Additionally, indicators of spore activity, such as respiration and permeability changes, were assessed. It is noteworthy that A. niger spores do not initiate germination utilizing their internal reserves. The introduction of glucose triggers heightened oxygen consumption and an increase in the overall concentration of organic acids. The initial 3-hour germination period is characterized by an augmentation in protein synthesis, along with a reduction in free amino acid concentration, which suggests the synthesis of proteins to facilitate germination. Furthermore, changes in permeability are observed to influence the release of various substances from the germinating spores. Significant alterations occur in the concentration of free sterols and the sterol-to-lipid ratio in germinating A. niger spores. During the early stages of germination, there is extensive degradation of phospholipids, particularly phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and their lyso-derivatives. However, these phospholipids are subsequently resynthesized in the later stages of germination. Regarding nonpolar lipids in A. niger spores, they consist primarily of hydrocarbons, triglycerides, fatty acids, sterol esters, and free sterols. Notably, the content of free sterols increases while the content of hydrocarbons decreases during the germination process in A. niger spores.

Characterization of Seed Oil from Six In Situ Collected Wild Amaranthus Species

Six Amaranthus species (A. cruentus, A. hybridus, A. hypochondriacus, A. muricatus, A. tuberculatus, and A. viridis) were collected in Italy (wild habitats) from crops and roadsides. Amaranth seed oil was extracted to obtain fractions rich in squalene. Squalene, free fatty acid, tocopherol, and sterol composition and content were investigated in detail. An analysis of variance and principal components was performed. The oil content in the seed ranged from 5.17% (A. muricatus) to 12.20% (A. tuberculatus). The quantity of squalene in the oil varied from 3.43% (A. muricatus) to 6.09% (A. hypochondriacus). The primary sterols were beta-sitosterol, brassicasterol, campesterol, and stigmasterol. The main tocopherols in all the samples were alfa-tocopherol, beta-tocopherol, and delta-tocopherol. Our results exhibited that the smallest seeds (A. tuberculatus) have the highest percentages of oil and squalene, whereas the largest seeds size (A. muricatus) show the lowest percentages. There is also evidence that the samples growing at lower altitudes show the highest concentration of fatty acids. According to our results, the six wild Amaranthus species exhibited similar characteristics to commercial species. This study confirms that the site of the collection has an impact on the oil and squalene content of the Amaranthus species.

Analysis of Free and Esterified Sterol Content and Composition in Seeds Using GC and ESI-MS/MS.

Total sterol content and composition in plant tissues can be easily determined by gas chromatography (GC) after saponification of the total lipid extract. However, in oleogenic tissues a significant proportion of the sterol is esterified to fatty acids, with GC methodologies unable to provide information about the proportion and the molecular species composition of intact steryl esters (SEs). Here we describe an electrospray ionization-tandem mass spectrometry (ESI-MS/MS) and Multiple Reaction Monitoring (MRM) method which, in parallel with GC analysis, allows for the accurate determination of both free and esterified sterol content and composition in seeds. After extraction of seed oil with hexane, free sterols are derivatized with undecanoyl chloride, total steryl esters are then purified from triacylglycerol (TAG) by liquid chromatography, infused and ionized as ammonium adducts, with molecular species identified and quantified by fragmentation in the presence of internal standards.

Metabolic profiling in serum, cerebrospinal fluid, and brain of patients with cerebrotendinous xanthomatosis

Cerebrotendinous xanthomatosis (CTX) is caused by autosomal recessive loss-of-function mutations in CYP27A1, a gene encoding cytochrome p450 oxidase essential for bile acid synthesis, resulting in altered bile acid and lipid metabolism. Here, we aimed to identify metabolic aberrations that drive ongoing neurodegeneration in some patients with CTX despite chenodeoxycholic acid (CDCA) supplementation, the standard treatment in CTX. Using chromatographic separation techniques coupled to mass spectrometry, we analyzed 26 sterol metabolites in serum and cerebrospinal fluid (CSF) of patients with CTX and in one CTX brain. Comparing samples of drug naive patients to patients treated with CDCA and healthy controls, we identified 7α,12α-dihydroxycholest-4-en-3-one as the most prominently elevated metabolite in serum and CSF of drug naive patients. CDCA treatment substantially reduced or even normalized levels of all metabolites increased in untreated patients with CTX. Independent of CDCA treatment, metabolites of the 27-hydroxylation pathway were nearly absent in all patients with CTX. 27-hydroxylated metabolites accounted for ∼45% of total free sterol content in CSF of healthy controls but <2% in patients with CTX. Metabolic changes in brain tissue corresponded well with findings in CSF. Interestingly, 7α,12α-dihydroxycholest-4-en-3-one and 5α-cholestanol did not exert toxicity in neuronal cell culture. In conclusion, we propose that increased 7α,12α-dihydroxycholest-4-en-3-one and lack of 27-hydroxycholesterol may be highly sensitive metabolic biomarkers of CTX. As CDCA cannot reliably prevent disease progression despite reduction of most accumulated metabolites, supplementation of 27-hydroxylated bile acid intermediates or replacement of CYP27A1 might be required to counter neurodegeneration in patients with progressive disease despite CDCA treatment.

A Rapid Gas Chromatographic Method for Direct Determination of Free Sterols in Animal and Vegetable Fats and Oils

In this study, a rapid and simple method without a derivatization process for determination of the free sterols in vegetable and animal oils was developed. A direct injection gas chromatography with a non-polar megabore column (DB-1, 5 m × 0.53 mm, 1μm) was used. The recoveries of cholesterol, campesterol, stigmasterol and β-sitosterol from lard were at the range of 89%-106% with a coefficient of variation less than 12%. Total sterols were determined using the same method after saponification of the oil sample. Fourteen samples, including olive oil, sunflower oil, peanut oil, soybean oil, sesame oil, lard and egg yolk oil, were quantitatively analyzed for total and free sterols. The contents of total cholesterol, brassicasterol, campesterol, stigmasterol, β-sitosterol, Δ5-avenasterol, Δ7-stigmastenol and Δ7-avenasterol in test samples were at the range of 193-34384, 0-1222, 0-2356, 0-1365, 0-5414, 0-608, 0-1296 and 0-129 μg/g, respectively; while the contents of free cholesterol, brassicasterol, campesterol, stigmasterol, β-sitosterol, Δ5-avenasterol, Δ7-stigmastenol and Δ7-avenasterol were 98-30340, 0-1057, 0-634, 0-724, 0-3087, 0-404, 0-558 and 0-23 μg/g, respectively. The amounts of esterified sterols were calculated by subtracting the free sterol contents from total sterol contents. Results showed olive oil, sunflower oil and peanut oil primarily contain esterified sterols; while soybean oil, sesame oil, lard and egg oil contain mostly free sterols. The developed method is recommended as a rapid method to determine if animal fats/oils are adulterated with vegetable oils.

THE COMPONENT COMPOSITION OF THE PHYTOSTEROLS OF THE AERIAL PART OF THE HORSETAIL VAR-IEGATED ЕQUISÉTUM VARIEGATUM SCHLEICH. EX. WEB. GROWING IN NORTH-EAST YAKUTIA

It is known that phytosterols have high immunomodulating, hypocholesterolemic and oncoprotective activity and are widely used in medicine. In addition, the plants containing them are used in feed of farm animals as dietary supplements that stimulate growth and the immune system. Promising, but poorly studied, sources of these biologically active compounds may be plants of the class Horsetails (Equisetopsida), grown under extreme conditions of sharply continental climate of Yakutia. The steric composition of the aerial part of the variegated horsetail (Equisétum variegatum) was studied for the first time during the summer and autumn vegetation. It is shown that the composition of the main free sterols includes β-sitosterol, campesterol, stigmasterol, isofucosterol, as well as a small amount of cholesterol. The total amount of free and bound sterols in the tissues of the aerial part of this species is about 0.5 mg/g dry weight or 2% of the total content of all lipid components. Moreover, the content of free sterols in the aerial part of variegated horsetail is an order of magnitude higher than the content of sterol esters in these tissues. Peculiarities of the seasonal (autumn-summer) dynamics of changes in the relative contents of stigmasterol, campesterol and isofucosterol and the absolute total content of sterols in the aerial part of variegated horsetail are revealed.

Assessment of free plant sterols in cold pressed Citrus essential oils

A fast, sensitive, accurate and robust GC-FID and confirmatory GC-MS method, was developed to simultaneously determine squalene and underivatized free plant sterols in Citrus essential oils (cEOs). The method was applied to assess the content of squalene and free plant sterols in four most commonly employed cold-pressed cEOs (bergamot, lemon, mandarin and orange). cEOs plant sterols exhibited distinctive molecular patterns, with levels ranging from 182 to 1100 mg kg−1 in lemon and bergamot essential oils, respectively. β-sitosterol was the dominant compound in all cases, with an average content of ∼650 mg kg−1 in bergamot and orange essential oils. Campesterol and brassicasterol occurred at much lower amount in all samples. Bergamot essential oil was also the richest in squalene (537 mg kg−1) compared to the other cEOs. The method developed could contribute to define compositional patterns of cEOs, thus supporting their versatile utilisation in the food and flavour industry.

Lipid composition of the spores of zygomycetous and ascomycetous fungi during cessation of the exogenous dormancy state

The composition of lipids and fatty acids was studied in the spores of exogenously dormant (spores 0) and germinating (spores G) spores in distilled water for sporangiospores of zygomycetous fungi Cunninghamella echinulata VKM F-663 and Umbelopsis ramanniana VKM F-582 and for conidia of ascomycetous fungi Aspergillus tamarii VKM F-64 and A. sydowii VKM F-441. Compared to spores 0, the lipids of spores G contained higher shares of unsaturated fatty acids, lower levels of massive phospholipids (phosphatidylcholine and phosphatidylethanolamine), and elevated levels of phosphatidylglycerol and phosphatidic acid. The level of cardiolipin, the main phospholipid of the mitochondrial membranes, increased when the spores of both zygomycetes exited from the dormant state. While a certain increase in the content of free and esterified sterols in the neutral lipids of the slowly germinating U. ramanniana G spores was observed, germination of sporangiospores and conidia of the studied fungi generally did not result in significant changes in the composition of the neutral lipid classes, which may be due to the fact that they are not the major reserve mobilized at the stage of exit from the dormant state.

Gas Chromatographic Determination and Method Validation of Stigmasterol, Î’-Sitosterol, Campesterol and Brassicasterol Contents of Turkish Cottonseed Oil Samples

Plant sterols are important agricultural products for human health and consequently, for nutrition industries. In the present study, free sterol contents of crude Turkish cottonseed oil samples have been determined in a single analytical run by using a solid phase extraction step prior to the detection with a gas chromatography coupled with a flame ionization detector. Free hydroxyl groups of Stigmasterol, β-Sitosterol, Campesterol and Brassicasterol were derivatized by using N-methyl-N-trimethylsilyl trifluoroacetamide to enhance their volatility and, sterol content of the samples were, then, separated from their matrix by using a octadecylsilane cartridge. The eluates were injected into the gas chromatographic system and satisfactory recovery ratios were obtained. After having validated the method, it was applied into the analysis for cottonseed oil samples for their free sterol levels.

The Content and Composition of Total, Free, and Esterified Sterols of Lotus Plumule Oil by GC–MS/FID

AbstractThis study investigated the content and composition of total, free, and esterified sterols of three varieties of lotus plumule oil (Hunan lotus, Jiangxi lotus, and Fujian lotus) using GC–MS/FID. The fatty acid composition of sterol fatty acid esters (SFAE) was also analyzed and compared with that of triglycerides. Results showed that total sterol of lotus plumule oil (12.10–14.21 g/100 g) was higher than that of other plant oils (corn germ oil, 1.11 g/100 g; rapeseed oil, 0.78 g/100 g). No significant difference was found among the total sterol contents of the three types of lotus plumule oils (p &gt; 0.05). Most sterol existed in ester forms (81.8–89.1%) rather than in free forms (8.4–10.1%). β‐Sitosterol (71.4–73.4%), and campesterol (6.2–7.5%) were the predominant fractions of free sterols. β‐Sitosterol (41.3–53.7%) and ∆5‐avenasterol (27.1–31.1%) were the predominant fractions of esterified sterols, followed by campesterol (12.1–13.0%) and ∆7‐avenasterol (3.4–3.7%). Linoleic acid (63.6–65.8%), oleic acid (8.3–10.4%), and behenic acid (9.0–9.9%) were the main fatty acids of SFAE, which were different from those of triglycerides. The results from this study suggest that lotus plumule oil may be a good resource of SFAE and can be used as a supplemental ingredient in functional foods.

Encapsulation of phytosterols and phytosterol esters in liposomes made with soy phospholipids by high pressure homogenization.

Phytosterols and phytosterol esters were encapsulated within large unilamellar liposomes prepared with soy phospholipids using a microfluidizer. The average particle diameter of these liposomal vesicles increased with increasing amounts of encapsulated phytosterols, especially with increasing free sterol content. The phytosterol content, liposomal particle size, and phytosterol encapsulation efficiency started to plateau when liposomes were prepared with MOPS buffer dispersions that contained 50 mg ml-1 soy phospholipid and more than 4% phytosterol blend, suggesting the saturation of phytosterol encapsulation. We proposed an encapsulation mechanism of free sterols and phytosterol esters in liposomes, where free sterols were mainly encapsulated within the lumen of these liposomes as crystals, and sterol esters and some free sterols were incorporated within the phospholipid bilayer of the liposomal membrane. The results from this work could provide the pharmaceutical and nutraceutical industries a practical method to produce loaded liposomes using inexpensive phospholipid mixtures for the delivery of bioactive ingredients.

Characterization of Arabidopsis sterol glycosyltransferase TTG15/UGT80B1 role during freeze and heat stress

Sterol glycosyltransferases regulate the properties of sterols by catalyzing the transfer of carbohydrate molecules to the sterol moiety for the synthesis of steryl glycosides and acyl steryl glycosides. We have analyzed the functional role of TTG15/UGT80B1 gene of Arabidopsis thaliana in freeze/thaw and heat shock stress using T-DNA insertional sgt knockout mutants. Quantitative study of spatial as well as temporal gene expression showed tissue-specific and dynamic expression patterns throughout the growth stages. Comparative responses of Col-0, TTG15/UGT80B1 knockout mutant and p35S:TTG15/UGT80B1 restored lines were analyzed under heat and freeze stress conditions. Heat tolerance was determined by survival of plants at 42°C for 3 h, MDA analysis and chlorophyll fluorescence image (CFI) analysis. Freezing tolerance was determined by survival of the plants at -1°C temperature in non-acclimatized (NA) and cold acclimatized (CA) conditions and also by CFI analysis, which revealed that, p35S:TTG15/UGT80B1 restored plants were more adapted to freeze stress than TTG15/UGT80B1 knockout mutant under CA condition. HPLC analysis of the plants showed reduced sterol glycoside in mutant seedlings as compared to other genotypes. Following CA condition, both β-sitosterol and sitosterol glycoside quantity was more in Col-0 and p35S:TTG15/UGT80B1 restored lines, whereas it was significantly less in TTG15/UGT80B1 knockout mutants. From these results, it may be concluded that due to low content of free sterols and sterol glycosides, the physiology of mutant plants was more affected during both, the chilling and heat stress.

Characterization of sunflower oils obtained separately by pressing and subsequent solvent extraction from a new line of seeds rich in phytosterols and conventional seeds

In this study we evaluate the chemical composition of sunflower oils obtained separately by pressing and subsequent solvent extraction from a new seeds rich in phytosterols (IASP-18) and conventional seeds (HA-89). Results have shown that the total content of oil was much lower in the IASP-18 (18.1%) than in the conventional (37.5%) seeds. The extraction yield obtained by pressing was as low as 3% in the IASP-18 seeds and 37.5% in HA-89, while in the solvent extraction it was of the same order (~18 wt% on seeds extracted by pressing) for the two types of seeds. No significant changes in the fatty acid composition were found between the oils extracted by the two procedures, but the pressed oils presented significantly lower acidity and larger content of the unsaponifiable fraction. Expressed as free sterols, the total sterols were 37–38% more concentrated in the oils extracted with solvent, reaching amounts of 13 700 and 6500 mg/kg in the IASP-18 and HA-89 oils, respectively. No substantial differences were found in the composition of total sterols analysed as free sterols between the oils extracted with the two procedures, but the contents of free sterols and sterol glycosides were much higher in the oils extracted with solvent.

ИЗУЧЕНИЕ СОДЕРЖАНИЯ ФИТОСТЕРИНОВ В АНАТОМИЧЕСКИХ ЧАСТЯХ БОЯРЫШНИКА КРОВАВО-КРАСНОГО

We investigated the content of free and associated sterols in anatomy parts of the crataegus sangunea in the course of the annual cycle. The work presents the dynamics of studying changes in the content of sterols in the shoots, leaves, and fruits. It is established, that acid esters and glycosides sterols contain in its composition limits and unsaturated acids, the content of which in the course of the growing season changes.

Extractives of mechanically wounded wood and knots in beech

Abstract Various types of wound-associated wood, such as discoloured wood including knots of living and dead branches, were sampled from common beech trees (Fagus sylvatica L.), extracted, and the extracts have been analysed by GC and colourimetry assay. Sequential pressurised solvent extraction was applied with cyclohexane and aqueous methanol. The yield of hydrophilic compounds was three to five times higher than that of lipophilic extractives. The fractions differed mainly in their hydrophilic moieties. The lipophilic extractives consisted mainly of free fatty acids, fatty alcohols and free sterols. The yield of fatty acids was slightly higher in reaction zones and knots. The content of free sterols was highest in the reaction zones and in the discoloured wood. The hydrophilic extractives consisted of soluble sugars, various acids and phenolic compounds with catechin as the dominant one. Expectedly, the yield of phenolic extractives and catechin (proanthocyanidins) was highest in knots and wound-wood. Discoloured wood gave rise to lower amounts of catechin.

Minor Constituents in Canola Oil Processed by Traditional and Minimal Refining Methods

AbstractThe minimal refining method described in the present study made it possible to neutralize crude canola oil with Ca(OH)2, MgO, and Na2SiO3 as alternatives to NaOH. After citric acid degumming, about 98 % of the phosphorous content was removed from crude oil. The free fatty acid content after minimal neutralization with Ca(OH)2 decreased from 0.50 to 0.03 %. Other quality parameters, such as peroxide value, anisidine value, and chlorophyll content, after traditional and minimal neutralization were within industrial acceptable levels. The use of Trisyl silica and Magnesol R60 made it feasible to remove the hot‐water washing step and decreased the amount of residual soap to &lt;10 mg/kg oil. There were no significant changes in chemical characteristics of canola oil after using wet and dry bleaching methods. During traditional neutralization, the total tocopherol loss was 19.6 %, while minimal refining with Ca(OH)2, MgO, and Na2SiO3 resulted in 7.0, 2.6, and 0.9 % reductions in total tocopherols. Traditional refining removed 23.6 % of total free sterols, while after minimal refining free sterols content did not change. Both traditional and minimal refining resulted in almost complete removal of polyphenols from canola oil. Total phytosterols and tocopherols in two cold‐pressed canola oils were 774 and 836 mg/100 g, and 366 and 354 mg/kg, respectively. The minimal refining method described in the present study was a new practical approach to remove undesirable components from crude canola oil meeting commercial refining standards while preserving more healthy minor components.

Influence of baking and in vitro digestion on steryl ferulates from wheat

So far, data on absorption and metabolism of steryl ferulates from edible sources is scarce. Therefore, the impact of enzyme-aided baking and in vitro digestion was examined in this study. Wheat flours and wheat breads were subjected to a static in vitro digestion model and changes in the contents of steryl ferulates and free sterols (possible hydrolysis products of steryl ferulates) were monitored. Baking degraded steryl ferulates at a similar rate in all types of breads (43–47%) compared to the corresponding flours, while baking induced changes in free sterols showed no clear pattern. In vitro digestion provoked five folds lower content of steryl ferulates in flours than in breads and it also resulted in significant free sterol accumulation. Interestingly, bioaccessibility (0.01–0.25%) was not influenced by the cereal matrix. The four steryl ferulate species, which were detected in wheat, showed similar hydrolysis rates during digestion. As baking had a significant impact on the steryl ferulate content of wheat, we suggest that both raw and processed sources should be considered further in vitro, animal or human trials, when studying the metabolic fate of steryl ferulates.

Quantification of sterol lipids in plants by quadrupole time-of-flight mass spectrometry

Glycerolipids, sphingolipids, and sterol lipids constitute the major lipid classes in plants. Sterol lipids are composed of free and conjugated sterols, i.e., sterol esters, sterol glycosides, and acylated sterol glycosides. Sterol lipids play crucial roles during adaption to abiotic stresses and plant-pathogen interactions. Presently, no comprehensive method for sterol lipid quantification in plants is available. We used nanospray ionization quadrupole-time-of-flight mass spectrometry (Q-TOF MS) to resolve and identify the molecular species of all four sterol lipid classes from Arabidopsis thaliana. Free sterols were derivatized with chlorobetainyl chloride. Sterol esters, sterol glycosides, and acylated sterol glycosides were ionized as ammonium adducts. Quantification of molecular species was achieved in the positive mode after fragmentation in the presence of internal standards. The amounts of sterol lipids quantified by Q-TOF MS/MS were validated by comparison with results obtained with TLC/GC. Quantification of sterol lipids from leaves and roots of phosphate-deprived A. thaliana plants revealed changes in the amounts and molecular species composition. The Q-TOF method is far more sensitive than GC or HPLC. Therefore, Q-TOF MS/MS provides a comprehensive strategy for sterol lipid quantification that can be adapted to other tandem mass spectrometers.

The effect of radish plant rotation around a vertical axis on leaf morphology and lipid composition

The effects of radish (Raphanus sativus L. var. radicula D.C., cv. Rozovo-krasnyi s belym konchikom) plant clockwise rotation (2 rpm) around the vertical axis during their growth on growth parameters and also on the composition and content of polar lipids (PL) and neutral lipids (NL) in plant leaves and fatty acids included in them were studied. Rotation in the plane of the Earth’s magnetic field horizontal component did not affect the number of leaves but declined their total mass by 25%. However, a reduction of the root mass was observed only at elevated temperature. Rotation reduced the ratio of PL to NL by 1.5–2.0 times as compared with control, decreasing the content of such PL as glycoand phospholipids and increasing the content of NL, triacylglycerols and free sterols. Among glycolipids, the content of monogalactosyldiacylglycerols and digalactosyldiacylglycerols was reduced in comparison with stationary control, and among phospholipids the content of phosphatidylcholin was reduced by ∼50%. The ratio of phospholipids to sterols was reduced more than by 30%, indirectly indicating the decreased fluidity of the lipid bilayer of membranes; the ratio PL/NL was reduced as well, indicating an acceleration of age-dependent changes in the rotated plants. Rotation increased the content of linolenic acid and reduced the contents of oleic and erucic acids, thus increasing the index of fatty acid desaturation. We concluded that radish plant clockwise rotation around the vertical axis is an unfavorable factor inducing the appearance of the signs of premature senescence.

The Role of Arv1 in Sterol Metabolism and its Contribution to the Unfolded Protein Response

Proper sterol distribution within the cell is a critical component of membrane homeostasis. The endoplasmic reticulum (ER)‐localized protein Arvl mediates sterol transport from the ER to the plasma membrane. Alterations in ER sterol distribution are a stimulus for unfolded protein response (UPR) activation. We hypothesize that the loss of Arv1p in yeast will increase the free sterol (FS) content of the ER, resulting in UPR induction. The UPR will also be induced in primary murine macrophages where ARV1 expression has been knocked down. Loss of yeast Arv1p function results activation of the UPR, mediated by Ire1p. The yeast arv1Δ ire1Δ homozygous haploid is inviable. Mutant ire1 core luminal domains, defective in sensing unfolded proteins, rescue the lethality of the arv1Δ ire1Δ haploid; these strains exhibited increased UPR induction that was synergistic with protein misfolding. We also demonstrate that decreased ARV1 expression in mammalian cells results in UPR induction, particularly an upregulation of CHOP. As a result of ARV1 knockdown, macrophages undergo apoptosis due to prolonged UPR induction and FS‐induced cytotoxicity. We demonstrate that defects in ER homeostasis, as a result of changes in ARV1 expression, exhibit UPR induction in both yeast and mammalian systems. The UPR appears to be a generalized response, resulting from perturbations in membrane structure, lipid metabolism and protein folding.