RESUMO
Sterol 14α-demethylases (CYP51s) are a ubiquitous superfamily of cytochrome P450 enzymes that play an essential role in sterol biosynthesis. As fungal CYP51s are the target of azole-based antifungal agents, which are facing the problem of increasing resistance, the substrate specificity of this enzyme subclass has recently garnered significant attention. Herein we report the first chemical synthesis of the final endogenous substrate of this enzyme class, obtusifoliol, in 1.3% yield across ten steps from a commercially available lanosterol mixture. Intermediates along this pathway provide a basis for further derivatisation of the sterol skeleton and future investigation into CYP51 inhibition to overcome pathogens' azole resistance.
Assuntos
Antifúngicos , Lanosterol , Antifúngicos/farmacologia , Azóis/farmacologia , Colestadienóis , Sistema Enzimático do Citocromo P-450/metabolismo , Lanosterol/metabolismo , Esterol 14-Desmetilase/metabolismo , EsteróisRESUMO
In the present work, a dispersive liquid-liquid microextraction approach has been developed for extraction of four phytosterols (stigmasterol, ß-sitosterol, campesterol, and brassicasterol) from cow milk samples using organic and deep eutectic solvents and the results were critically compared. The extracted analytes were determined using high performance liquid chromatography. In the developed method, carbon tetrachloride and choline chloride:p-chlorophenol deep eutectic solvent were selected to use as the best extraction solvent. Effective parameters and validation data were studied for both methods, independently. Under optimum conditions, limits of detection and quantification were within the ranges of 0.3-0.9 and 1.0-3.0 ng/mL for organic solvent based dispersive liquid-liquid microextraction and 0.09-0.32 and 0.3-1.0 ng/mL for deep eutectic solvent based dispersive liquid-liquid microextraction, respectively. Good coefficient of determinations and relative standard deviations obtained for the methods were ≥0.994 and ≤7.6%, respectively. The introduced method was performed on different milk samples for the determination of target analytes using both solvents and the results were analyzed statistically by the t-test.
Assuntos
Leite/química , Fitosteróis/análise , Animais , Colestadienóis/análise , Colesterol/análogos & derivados , Colesterol/análise , Cromatografia Líquida de Alta Pressão/métodos , Solventes Eutéticos Profundos/análise , Contaminação de Alimentos/análise , Limite de Detecção , Microextração em Fase Líquida/métodos , Resíduos de Praguicidas/análise , Solventes/análiseRESUMO
We investigated the main sterols, phytosterols, and the α- and γ-tocopherol content in donkey milk during the first 2 mo of lactation. Cholesterol was the main sterol in milk (mean ± standard deviation = 0.97 ± 0.443 g/100 g of fat). Lanosterol was the main minor sterol of animal origin, followed by desmosterol (0.003 ± 0.001 and 0.001 ± 0.001 g/100 g of fat, respectively). Of the phytosterols, ß-sitosterol was the main sterol of vegetal origin in donkey milk (0.005 ± 0.002 g/100 g of fat), but lower levels of campesterol, brassicasterol, and stigmasterol were also recorded. Mean levels of α- and γ-tocopherol were 0.01 ± 0.007 and 0.003 ± 0.001 g/100 g of fat, respectively. We observed no significant changes in sterol or tocopherol content during the first 2 mo of lactation. The presence of lanosterol in donkey milk is of particular interest, because lanosterol is a potential drug and has important physiological effects. The presence of phytosterols, which are considered nutraceutical molecules, enhances the nutritional quality of donkey milk fat for consumers.
Assuntos
Equidae , Leite/química , Fitosteróis/análise , Tocoferóis/análise , Animais , Colestadienóis , Colesterol/análogos & derivados , Colesterol/análise , Desmosterol/análise , Feminino , Lactação/metabolismo , Lanosterol/análise , Valor Nutritivo , Saponinas/metabolismo , Sitosteroides , EsteróisRESUMO
Enzymatic hydroxylation of unactivated primary carbons is generally associated with the use of molecular oxygen as co-substrate for monooxygenases. However, in anaerobic cholesterol-degrading bacteria such as Sterolibacterium denitrificans the primary carbon of the isoprenoid side chain is oxidised to a carboxylate in the absence of oxygen. Here, we identify an enzymatic reaction sequence comprising two molybdenum-dependent hydroxylases and one ATP-dependent dehydratase that accomplish the hydroxylation of unactivated primary C26 methyl group of cholesterol with water: (i) hydroxylation of C25 to a tertiary alcohol, (ii) ATP-dependent dehydration to an alkene via a phosphorylated intermediate, (iii) hydroxylation of C26 to an allylic alcohol that is subsequently oxidised to the carboxylate. The three-step enzymatic reaction cascade divides the high activation energy barrier of primary C-H bond cleavage into three biologically feasible steps. This finding expands our knowledge of biological C-H activations beyond canonical oxygenase-dependent reactions.
Assuntos
Trifosfato de Adenosina/metabolismo , Betaproteobacteria/metabolismo , Anaerobiose , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Betaproteobacteria/genética , Carbono/química , Colestadienóis/química , Colestadienóis/metabolismo , Colesterol/química , Colesterol/metabolismo , Genes Bacterianos , Hidroliases/genética , Hidroliases/metabolismo , Hidroxilação , Oxigenases de Função Mista/genética , Oxigenases de Função Mista/metabolismo , Modelos Biológicos , Oxirredução , Filogenia , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Água/metabolismoRESUMO
We previously revealed that Choreito, a traditional Kampo medicine, strongly inhibits bladder carcinogenesis promotion. We have also shown that Polyporus sclerotium, which is one of the crude drugs in Choreito, has the strongest bladder carcinogenesis inhibitory effect and that the ergosterol contained in Polyporus sclerotium is the main active component. In this study, we analyzed the mechanism by which ergosterol inhibits bladder carcinogenesis. Rats were given an N-butyl-N-(4-hydroxybutyl) nitrosamine (BHBN) solution ad libitum, and then a promoter [saccharin sodium (SS), DL-tryptophan, or BHBN] was administered together with ergosterol or its metabolite, brassicasterol. The bladders were removed from rats, and the inhibitory effect on carcinogenesis promotion was evaluated by an agglutination assay with concanavalin A (Con A). Although the oral administration of ergosterol inhibited the promotion of bladder carcinogenesis with SS, the intraperitoneal administration of brassicasterol showed a stronger effect. The effect of brassicasterol on carcinogenesis promotion was observed regardless of the type of promoter. Administration of testosterone to castrated rats increased the number of cell aggregates caused by Con A. In contrast, intraperitoneal administration of brassicasterol to castrated rats treated with testosterone significantly decreased the number of cell aggregates, confirming the inhibition of bladder carcinogenesis promotion. The inhibitory effect of ergosterol on bladder carcinogenesis is due to brassicasterol, a metabolite of ergosterol. The action of brassicasterol via androgen signaling may play a role in the inhibitory effect on bladder carcinogenesis promotion.
Assuntos
Colestadienóis/uso terapêutico , Ergosterol/uso terapêutico , Fitosteróis/uso terapêutico , Neoplasias da Bexiga Urinária/tratamento farmacológico , Animais , Colestadienóis/farmacologia , Ergosterol/farmacologia , Humanos , Masculino , Medicina Kampo , Fitosteróis/farmacologia , Ratos , Ratos WistarRESUMO
The objective of this study is to review the compliance of fatty acid compositions of Thai and India rice bran oil and level of desmethylsterols of Thai crude rice bran oil with the Codex Standard for Named Vegetable Oil (Codex Stan 210-1999). Fatty acid compositions of 90 samples of Thai and India refined rice bran oil were analyzed by capillary gas liquid chromatography. The results indicated that the contents of the C14:0, C18:2, C22:0 and C24:0 possible fall outside the range of Codex Stan 210-1999. In addition, sterol profile content of 40 samples of crude rice bran oil from Thai refinery plants were studied. The test results of major compositions of desmethylsterols are in good agreement with CODEX STAN 210-1999 except for Brassicasterol and other desmethylsterols. Accordingly, these data were proposed to corporate into the codex standard. Consequently, Codex agreed to amend the fatty acid composition of C14:0, C18:2, C22:0 and C24:0 from ND to 1.0, 21 to 42, ND to 1.0 and ND to 0.9 % and broaden level of Brassicasterol and other desmethylsterols to "ND-0.3" and to "7.5-12.8" accordingly.
Assuntos
Ácidos Graxos/análise , Análise de Alimentos/normas , Qualidade dos Alimentos , Óleos de Plantas/normas , Óleo de Farelo de Arroz/análise , Óleo de Farelo de Arroz/normas , Povo Asiático , Colestadienóis/análise , Cromatografia Gasosa , Humanos , Índia , Fitosteróis/análiseRESUMO
This study investigated the effect of blanching pomegranate seeds (PS) on oil yield, refractive index (RI), yellowness index (YI), conjugated dienes (K232), conjugated trienes (K270), total carotenoid content (TCC), total phenolic compounds (TPC) and DPPH radical scavenging of the extracted oil. Furthermore, phytosterol and fatty acid compositions of the oil extracted under optimum blanching conditions were compared with those from the oil extracted from unblanched PS. Three different blanching temperature levels (80, 90, and 100 °C) were studied at a constant blanching time of 3 min. The blanching time was then increased to 5 min at the established optimum blanching temperature (90 °C). Blanching PS increased oil yield, K232, K270, stigmasterol, punicic acid, TPC and DPPH radical scavenging, whereas YI, ß-sitosterol, palmitic acid and linoleic acid were decreased. The RI, TCC, brassicasterol, stearic acid, oleic acid and arachidic acid of the extracted oil were not significantly (p > 0.05) affected by blanching. Blanching PS at 90 °C for 3 to 5 min was associated with oil yield, TPC and DPPH. Blanching PS at 90 °C for 3 to 5 min will not only increase oil yield but could also improve functional properties such as antioxidant activity, which are desirable in the cosmetic, pharmaceutical, nutraceutical and food industries.
Assuntos
Antioxidantes/química , Carotenoides/química , Óleos de Plantas/química , Punica granatum/química , Sementes/química , Compostos de Bifenilo/química , Colestadienóis/química , Suplementos Nutricionais , Ácidos Eicosanoicos/química , Ácidos Graxos/química , Tecnologia de Alimentos , Sequestradores de Radicais Livres/química , Ácido Linoleico/química , Ácidos Linolênicos/química , Ácido Oleico/química , Fenol/química , Fenóis/química , Fitosteróis/química , Picratos/química , Refratometria , Ácidos Esteáricos/química , TemperaturaRESUMO
Monogenic familial hypercholesterolemia is characterized by impaired cellular uptake of apolipoprotein B containing lipoproteins. However, its consequences on whole-body cholesterol metabolism are unclear. We investigated cholesterol metabolism in wild-type mice (control) and in knockout (KO) mice for the low-density lipoprotein receptor (LDLR-KO) and for apolipoprotein E (apoE-KO) containing the genetic basis of the C57BL/6J mice, under a cholesterol-free diet. Cholesterol and "non-cholesterol" sterols (cholestanol, desmosterol, and lathosterol) were measured in plasma, tissues, as well as in feces as cholesterol and its bacterial modified products (neutral sterols) using gas chromatography/mass spectrometry, and bile acids were measured by an enzymatic method. Compared to controls, LDLR-KO mice have elevated plasma and whole-body cholesterol concentrations, but total fecal sterols are not modified, characterizing unaltered body cholesterol synthesis together with impaired body cholesterol excretion. ApoE-KO mice presented the highest concentrations of plasma cholesterol, whole-body cholesterol, cholestanol, total fecal sterols, and cholestanol, compatible with high cholesterol synthesis rate; the latter seems attributed to elevated body desmosterol (Bloch cholesterol synthesis pathway). Nonetheless, whole-body lathosterol (Kandutsch-Russel cholesterol synthesis pathway) decreased in both KO models, likely explaining the diminished fecal bile acids. We have demonstrated for the first time quantitative changes of cholesterol metabolism in experimental mouse models that explain differences between LDLR-KO and apoE-KO mice. These findings contribute to elucidate the metabolism of cholesterol in human hypercholesterolemia of genetic origin.
Assuntos
Colestadienóis , Colesterol , Hipercolesterolemia/metabolismo , Metabolismo dos Lipídeos , Animais , Colestadienóis/sangue , Colestadienóis/metabolismo , Colesterol/sangue , Colesterol/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout para ApoERESUMO
A novel liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed and validated to simultaneously quantify phytosterols (brassicasterol, campesterol, stigmasterol and ß-sitosterol) and tocopherols (alpha, beta, gamma and delta) entrapped in the lipid bilayer of a liposomal formulation. Apart from liposomes (a pharmaceutical product), the developed method was able to quantify target analytes in agricultural products, thus showing wide applications. Atmospheric pressure chemical ionization (APCI) was employed due to the enhanced ionization of phytosterols and tocopherols in comparison to electrospray ionization. Unlike published work, the chromatographic conditions were modified to simplify the analytical approach. For the first time, a simple isocratic elution (acetonitrile:methanol 99:1 v/v) was utilized for the separation of four phytosterols and four tocopherols in a single run. A substantially better baseline separation of phytosterols were obtained in comparison to reported methods by using poroshell C18 column. The method has a total run time of 7â¯min, which is the shortest run time among all reported quantitative methods for the simultaneous determination of four phytosterols and four tocopherols. Calibration curves for all phytosterols were linear in the range of 0.05-10⯵g/mL. In the case of tocopherols, alpha tocopherol showed linear response in the range of 0.25-10⯵g/mL. However, gamma and delta tocopherols exhibited quadratic relationship in the same concentration range (0.25-10⯵g/mL). Validation parameters met the International Conference on Harmonization (ICH) guidelines in terms of selectivity, accuracy, precision, repeatability, sensitivity, matrix effects, dilution integrity and stability. The method was, for the first time, successfully applied for the quantifying phytosterols and tocopherols entrapped inside liposomes. An interesting chromatographic phenomenon was observed during sample analysis. Alpha tocopherol (entrapped in the liposomal lipid bilayer) was found to elute at two retention times, 2.53â¯min and 3.60â¯min. Such dual separation was not observed in calibration standards and quality controls. It was concluded that the chiral recognition ability of liposomes made up of phosphatidylcholine separated the enantiomers of alpha tocopherol, giving rise to two peaks at two different retention time. To sum, the reported novel LC-MS/MS method addresses three major analytical shortcomings, namely i)longer run time, ii)complex gradient elution and iii)poor baseline separation of phytosterols and tocopherols.
Assuntos
Lipossomos/química , Fitosteróis/química , Tocoferóis/química , Pressão Atmosférica , Calibragem , Colestadienóis/química , Colesterol/análogos & derivados , Colesterol/química , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida/métodos , Reprodutibilidade dos Testes , Sitosteroides/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Estigmasterol/química , Espectrometria de Massas em Tandem/métodosRESUMO
Milk fat adulteration is a common issue in Central Asia. To assess the current situation in the commercial milk market, 17 milk samples were checked for fatty acid (FA) and sterol profiles to detect potential adulteration using multivariate analysis. Analysis of FA and sterols was performed using gas chromatography with flame ionization detection and gas chromatography with mass-spectrometric detection, respectively. Cluster analysis of FA profiles revealed 3 types of milk samples: (1) samples containing a higher proportion of short-chain FA, (2) samples containing a higher proportion of long-chain FA, and (3) samples with significant amounts of C18 FA. Analysis of sterols showed that samples included (1) milk fat containing 100% cholesterol, sometimes with traces of phytosterols, (2) milk fat with high proportions of ß-sitosterol and campesterol, and (3) milk fat containing high proportions of brassicasterol. We found significant relationships between FA profiles and sterol profiles. The profiles were compared with vegetable oil patterns reported in the literature. More than 50% of the samples appeared to be counterfeited. We conclude that identification of adulteration in milk can be based solely on determination of sterol patterns.
Assuntos
Ácidos Graxos/análise , Contaminação de Alimentos/análise , Leite/química , Esteróis/análise , Animais , Colestadienóis/análise , Colesterol/análogos & derivados , Colesterol/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Fitosteróis/análise , Óleos de Plantas/análise , Sitosteroides/análiseRESUMO
The seed of five fruits and vegetables, which are often eaten by Chinese people, were selected as research objects to study the physicochemical properties, nutritional ingredients and antioxidant capacity of their seed oils. The fatty acid results indicated that the oleic acid was the main unsaturated fatty acid in almond oil and celery seed oil (content of 64.10% and 62.96%, respectively), and the wax gourd seed oil, watermelon seed oil and pumpkin seed oil were linoleic acid as the main unsaturated fatty acid (content of 72.45%, 76.77% and 47.35%, respectively). Unsaturated fatty acids are mainly located at the sn-2 position of the triacylglycerol (TAG), whereas saturated fatty acids are mainly located at the sn-1, 3 positions for the five seed oils. The pumpkin seed oil had certain advantages in terms of phytosterols and squalene (3716 and 2732 mg/kg, respectively). The high content of polyphenol for celery seed oil exhibits higher medicinal value. Polyphenols, and brassicasterols were have significant correlation with antioxidant capacity (p < 0.05, r = 0.890-0.998). The significant differences in nutrient composition between these fruits and vegetables seed oils indicate their unique value as food.
Assuntos
Antioxidantes , Frutas/química , Óleos de Plantas/química , Óleos de Plantas/farmacologia , Verduras/química , Fenômenos Químicos , China , Colestadienóis , Ácidos Graxos/análise , Ácidos Graxos/química , Ácidos Graxos/isolamento & purificação , Ácidos Graxos Insaturados/análise , Ácidos Graxos Insaturados/química , Ácidos Graxos Insaturados/isolamento & purificação , Ácidos Linoleicos/análise , Ácidos Linoleicos/isolamento & purificação , Ácido Oleico/análise , Ácido Oleico/isolamento & purificação , Fitosteróis , Polifenóis/análise , Polifenóis/isolamento & purificação , Esqualeno , Triglicerídeos/químicaRESUMO
INTRODUCTION: Steroid compounds are widely distributed in nature throughout scientific history. Living organisms such as animals and vegetables have steroids that show a significant effect on their vital activities. Sterols are key components of all eukaryotic cell membranes. METHODS: Steroidal compounds; 3ß-oxo-[1',3',2'-oxathiaphos-phalidine-2'-one] stigmast-5-ene and 3ß- oxo[1`,3`,2`-dioxaphosphalidine-2`-one]-stigmast-5-ene were successfully prepared using easily accessible 3ß-hydroxy stigmast-5-ene with phosphorous oxychloride (POCl3), 2- mercaptoethanol/ethylene glycol and triethylamine (Et3N) in dry diethyl ether. Products were obtained in semi-solid state and characterized using physicochemical techniques. RESULTS: The results of the bioassay showed that the synthesized compound containing the sulfur atom had antibacterial activity. Molecular docking was also done in order to show in silico antibacterial activity and to make out the probable binding mode of compound with the amino acid residues of protein. CONCLUSION: The results of the docking study showed that synthesized compound 2 had minimal binding energy with substantial affinity for the active site.
Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Colestadienóis/química , Colestadienóis/farmacologia , Antibacterianos/síntese química , Colestadienóis/síntese química , Escherichia coli/efeitos dos fármacos , Simulação de Acoplamento Molecular , Estrutura MolecularRESUMO
Sewage pollution is a principal factor of decreasing water quality, although it has not been considered a real impact in Amazonia that is still considered a pristine environment around the world. Thus, this study aimed to assess the levels of sewage contamination in sediments from three streams crossing Manausâ¯-â¯a Brazilian city of 2,403,796 inhabitants in the heart of the Amazon rain forest. Cholesterol, cholestanol, brassicasterol, ergosterol, stigmasterol, ß-sitosterol, campesterol, stigmastanol, coprostanol, and epicoprostanol levels were determined by liquid chromatography tandem mass spectrometry (LC-MS/MS). The fecal indicator, coprostanol, was found in high concentrations (509-12â¯830â¯ngâ¯g-1) and high relative proportions (21-54%) in all samples collected in the Mindu stream that crosses many heavily populated districts of the city, and in the Quarenta stream that crosses the Industrial District of Manaus. The sediments of the Tarumã-Açu stream also presented coprostanol; however, concentrations (Assuntos
Monitoramento Ambiental/métodos
, Rios/química
, Esteróis/análise
, Poluentes da Água/análise
, Poluição da Água/análise
, Qualidade da Água
, Biomarcadores/análise
, Brasil
, Colestadienóis/análise
, Colestanol/análise
, Colestanóis/análise
, Colesterol/análogos & derivados
, Colesterol/análise
, Cromatografia Líquida
, Contaminação de Medicamentos
, Fezes
, Sedimentos Geológicos/química
, Fitosteróis/análise
, Esgotos/análise
, Sitosteroides/análise
, Espectrometria de Massas em Tandem
RESUMO
The discovery and search for new antimicrobial molecules from insects and animals that live in polluted environments is a very important step in the scientific search for solutions to the current problem of antibiotic resistance. Previously, we have reported that the secondary metabolite with the antibacterial action discovered in scorpion. The current study further isolated three new compounds from Buthus martensii karsch, while compounds 1 and 2 possessed 5,22E-cholestadienol derivatives whose structure demonstrated broad spectrum bactericide activities. To explore the antibacterial properties of these new compounds, the result shows that compound 2 inhibited bacterial growth of both S. aureus and P. aeruginosa in a bactericidal rather than a bacteriostatic manner (MBC/MIC ratio ≤ 2). Similarly, with compound 1, a ratio of MBC/MIC ≤ 2 indicates bactericidal activity inhibited bacterial growth of P. aeruginosa. Remarkably, this suggests that two compounds can be classified as bactericidal agents against broad spectrum bactericide activities for 5,22E-cholestadienol derivatives from Buthus martensii karsch. The structures of compounds 1â»3 were established by comprehensive spectra analysis including two-dimensional nuclear magnetic resonance (2D-NMR) and high-resolution electrospray ionization-mass spectrometry (HRESI-MS) spectra. The antibacterial mechanism is the specific binding (various of bonding forces between molecules) using compound 1 or 2 as a ligand based on the different receptor proteins'-2XRL or 1Q23-active sites from bacterial ribosome unit A, and thus prevent the synthesis of bacterial proteins. This unique mechanism avoids the cross-resistance issues of other antibacterial drugs.
Assuntos
Antibacterianos/farmacologia , Colestadienóis/farmacologia , Escorpiões/química , Animais , Antibacterianos/química , Bactérias/efeitos dos fármacos , Colestadienóis/química , Espectroscopia de Ressonância Magnética , Testes de Sensibilidade Microbiana , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
Several feeding trials with Atlantic salmon fed naturally high phytosterol concentrations due to dietary rapeseed oil inclusion have shown changes in lipid metabolism and increased hepatic lipid storage in the fish. An in vitro trial with Atlantic salmon hepatocytes was, therefore, performed to study the possible direct effects of phytosterols on lipid storage and metabolism. The isolated hepatocytes were exposed to seven different sterol treatments and gene expression, as well as lipid accumulation by Oil Red O dyeing, was assessed. Fucosterol, a sterol found in many algae species, had an effect on the size of individual lipid droplets, leading to smaller lipid droplets than in the control without added sterols. A sterol extract from soybean/rapeseed led to an increase in the percentage of hepatocytes with visible lipid droplets at 20× magnification, while hepatocytes of both the sterol extract-treated groups and fucosterol-treated groups had a larger proportion of their area covered with lipids compared to control cells. Brassicasterol, a sterol characteristic of rapeseed oil, was the only sterol treatment leading to a change in gene expression, affecting the expression of the nuclear receptors, peroxisome proliferator-activated receptor gamma (pparg) and retinoid X receptor (rxr). The current study thus shows that phytosterols can have direct, although subtle, effects on both hepatic lipid storage and gene expression of Atlantic salmon in vitro.
Assuntos
Colestadienóis/farmacologia , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Lipídeos , Fitosteróis/farmacologia , Salmão , Estigmasterol/análogos & derivados , Animais , Estigmasterol/farmacologiaRESUMO
The aim of the study was to investigate how the dietary sterol composition, including cholesterol, phytosterol:cholesterol ratio and phytosterols, affect the absorption, biliary excretion, retention, tissue storage and distribution of cholesterol and individual phytosterols in Atlantic salmon (Salmo salar L.). A feeding trial was conducted at two different temperatures (6 and 12°C), using nine different diets with varying contents of phytosterols, cholesterol and phytosterol:cholesterol ratio. Cholesterol retention values were clearly dependent on dietary cholesterol, and showed that fish fed cholesterol levels <1000 mg/kg feed produced considerable quantities of cholesterol de novo. Despite this production, cholesterol content increased with increasing dietary cholesterol in liver, plasma, bile, muscle, adipose tissue and whole fish at 12°C, and in plasma, bile and whole fish at 6°C. The tissue sterol composition generally depended on the dietary cholesterol content and on the dietary phytosterol:cholesterol ratio, but not on the dietary phytosterol content in itself. Campesterol and brassicasterol appeared to be the phytosterols with the highest intestinal absorption in Atlantic salmon. There was a high biliary excretion of campesterol, but not of brassicasterol, which accumulated in tissues and particularly in adipose tissue, with 2-fold-higher retention at 12°C compared with 6°C. Campesterol had the second highest retention of the phytosterols in the fish, but with no difference between the two temperatures. Other phytosterols had very low retention. Although brassicasterol retention decreased with increasing dietary phytosterols, campesterol retention decreased with increasing dietary cholesterol, indicating differences in the uptake mechanisms for these two sterols.
Assuntos
Dieta/veterinária , Salmo salar , Esteróis/análise , Animais , Colestadienóis/administração & dosagem , Colestadienóis/farmacocinética , Colesterol/administração & dosagem , Colesterol/análogos & derivados , Colesterol/farmacocinética , Absorção Intestinal , Fígado/metabolismo , Fitosteróis/administração & dosagem , Fitosteróis/farmacocinéticaRESUMO
Cell mortality is a key mechanism that shapes phytoplankton blooms and species dynamics in aquatic environments. Here we show that sterol sulfates (StS) are regulatory molecules of a cell death program in Skeletonema marinoi, a marine diatom-blooming species in temperate coastal waters. The molecules trigger an oxidative burst and production of nitric oxide in a dose-dependent manner. The intracellular level of StS increases with cell ageing and ultimately leads to a mechanism of apoptosis-like death. Disrupting StS biosynthesis by inhibition of the sulfonation step significantly delays the onset of this fatal process and maintains steady growth in algal cells for several days. The autoinhibitory activity of StS demonstrates the functional significance of small metabolites in diatoms. The StS pathway provides another view on cell regulation during bloom dynamics in marine habitats and opens new opportunities for the biochemical control of mass-cultivation of microalgae.
Assuntos
Diatomáceas/metabolismo , Microalgas/metabolismo , Fitoplâncton/metabolismo , Esteróis/metabolismo , Colestadienóis/metabolismo , Colestadienóis/toxicidade , Ésteres do Colesterol/metabolismo , Ésteres do Colesterol/toxicidade , Diatomáceas/citologia , Diatomáceas/efeitos dos fármacos , Ecossistema , Eutrofização/efeitos dos fármacos , Eutrofização/fisiologia , Microalgas/citologia , Microalgas/efeitos dos fármacos , Filogenia , Fitoplâncton/citologia , Fitoplâncton/efeitos dos fármacos , Fitosteróis/metabolismo , Fitosteróis/toxicidade , Transdução de Sinais , Sitosteroides/metabolismo , Sitosteroides/toxicidade , Esteróis/toxicidade , Sulfatos/metabolismo , Sulfatos/toxicidade , Sulfotransferases/genética , Sulfotransferases/metabolismoRESUMO
Ergosterol biosynthesis pathways essential to pathogenic protozoa growth and absent from the human host offer new chokepoint targets. Here, we present characterization and cell-based interference of Acanthamoeba spp sterol 24-/28-methylases (SMTs) that catalyze the committed step in C28- and C29-sterol synthesis. Intriguingly, our kinetic analyses suggest that 24-SMT prefers plant cycloartenol whereas 28-SMT prefers 24(28)-methylene lophenol in similar fashion to the substrate preferences of land plant SMT1 and SMT2. Transition state analog-24(R,S),25-epiminolanosterol (EL) and suicide substrate 26,27-dehydrolanosterol (DHL) differentially inhibited trophozoite growth with IC50 values of 7 nM and 6 µM, respectively, and EL yielded 20-fold higher activity than reference drug voriconazole. Against either SMT assayed with native substrate, EL exhibited tight binding â¼Ki 9 nM. Alternatively, DHL is methylated at C26 by 24-SMT that thereby, generates intermediates that complex and inactivate the enzyme, whereas DHL is not productively bound to 28-SMT. Steroidal inhibitors had no effect on human epithelial kidney cell growth or cholesterol biosynthesis at minimum amoebicidal concentrations. We hypothesize the selective inhibition of Acanthamoeba by steroidal inhibitors representing distinct chemotypes may be an efficient strategy for the development of promising compounds to combat amoeba diseases.
Assuntos
Acanthamoeba/efeitos dos fármacos , Colestadienóis/farmacologia , Lanosterol/análogos & derivados , Metiltransferases/metabolismo , Fitosteróis/farmacologia , Proteínas de Protozoários/metabolismo , Triterpenos/farmacologia , Acanthamoeba/enzimologia , Acanthamoeba/genética , Sequência de Aminoácidos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Colestadienóis/metabolismo , Desenho de Fármacos , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Expressão Gênica , Humanos , Rim/citologia , Cinética , Lanosterol/metabolismo , Lanosterol/farmacologia , Metiltransferases/antagonistas & inibidores , Metiltransferases/genética , Fitosteróis/metabolismo , Ligação Proteica , Proteínas de Protozoários/antagonistas & inibidores , Proteínas de Protozoários/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Esteróis/metabolismo , Especificidade por Substrato , Triterpenos/metabolismoRESUMO
This study aimed to investigate the effect of metal ions on the degradation of phytosterols in oils. The oil was heated at 180°C for 1h with/without addition of Fe3+, Fe2+, Cu2+, Mn2+, Zn2+, Na+, Al3+ and Mg2+. Variations of ß-sitosterol, stigmasterol, campesterol, brassicasterol and their degradation products were confirmed by the GC-MS analysis. In general, the increase of the metal ion concentration resulted in more phytosterol degradation, and the ability of metal ions following decreasing order: Fe3+>Fe2+>Mn2+≥Cu2+≥Zn2+>Na+≥Mg2+>Al3+. Metal ions significantly induced phytosterol autoxidation on C5, C6 and C7 on Ring B of steroid nucleus at even a low concentration, and induced dehydration on the C3 hydroxyl to form dienes and trienes at high concentration. The metal ions in oils are accounted for increasing phytosterol degradation, which decreases food nutritional quality and gives rise to the formation of undesirable compounds.
Assuntos
Temperatura Alta , Óleos/química , Fitosteróis/química , Esteroides/química , Antioxidantes/análise , Colestadienóis/análise , Colesterol/análogos & derivados , Colesterol/análise , Análise de Alimentos , Manipulação de Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Valor Nutritivo , Fitosteróis/análise , Sitosteroides/análise , Estigmasterol/análiseRESUMO
OBJECTIVE: To show the importance of measuring cholesterol precursor levels in amniotic fluid in all pregnancies with ultrasound features (such as holoprosencephaly) suggestive of Smith-Lemli-Opitz syndrome (SLOS), after exclusion of chromosomal anomalies. CASE REPORT: A 28-year-old woman, gravida 1 para 0, performed chorionic villus sampling for fetal karyotyping at 13 weeks of gestation due to positive combined first trimester screening in a fetus with increased nuchal translucency and suspected holoprosencephaly. The result was normal - 46,XX. The diagnosis of alobar holoprosencephaly was confirmed at 15 weeks of gestation, and cardiac and limb defects were also identified. Thus, a syndromic cause was considered, specifically a chromosomal microdeletion syndrome or a monogenic entity such as SLOS. The latter was confirmed by measuring 7-dehydrocholesterol (7DHC) and 8-dehydrocholesterol (8DHC) in amniotic fluid. Molecular analysis of DHCR7 gene identified a homozygous mutation in intron 8, c.964-1G>C, providing molecular confirmation for this diagnosis. CONCLUSION: The differential diagnosis of holoprosencephaly is broad. Identification of the cause of holoprosencephaly aids in establishing the prognosis and is essential to ascertain the mode of inheritance for adequate genetic counseling.