Vitamin E comprises eight related compounds: α-, β-, γ-, δ-tocopherols and α-, β-, γ-, δ-tocotrienols. In the past, α-tocopherol has been the isomer that was studied most, and its anti-inflammatory and anti-proliferative effects have been described. Therefore, many prevention trials have investigated the effect of α-tocopherol on human health. Current research studies have also defined the important roles of other tocopherols, such as anti-inflammatory, anti-proliferative and cancer preventative effects. Knowledge of the individual tocopherols could help to understand their roles in various metabolic pathways. This review summarizes the recent trends in sample pretreatment, liquid chromatography and selected applications of the determination of tocopherols in various biological materials. The relationship between tocopherol isomers and serious diseases is also described. Graphical Abstract Article structure.

• MeSH
• lidé MeSH
• tělesné tekutiny chemie   MeSH
• tokoferoly analýza   MeSH
• vysokoúčinná kapalinová chromatografie metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

Ectotherm animals including insects are known to undergo seasonal restructuring of the cell membranes in order to keep their functionality and/or protect their structural integrity at low body temperatures. Studies on insects so far focused either on fatty acids or on composition of molecular species in major phospholipid classes. Here we extend the scope of analysis and bring results on seasonal changes in minor phospholipid classes, lysophospholipids (LPLs), free fatty acids, phytosterols and tocopherols in heteropteran insect, Pyrrhocoris apterus. We found that muscle tissue contains unusually high amounts of LPLs. Muscle and fat body tissues also contain high amounts of β-sitosterol and campesterol, two phytosterols derived from plant food, while only small amounts of cholesterol are present. In addition, two isomers (γ and δ) of tocopherol (vitamin E) are present in quantities comparable to, or even higher than phytosterols in both tissues. Distinct seasonal patterns of sterol and tocopherol concentrations were observed showing a minimum in reproductively active bugs in summer and a maximum in diapausing, cold-acclimated bugs in winter. Possible adaptive meanings of such changes are discussed including: preventing the unregulated transition of membrane lipids from functional liquid crystalline phase to non-functional gel phase; decreasing the rates of ion/solute leakage; silencing the activities of membrane bound enzymes and receptors; and counteracting the higher risk of oxidative damage to PUFA in winter membranes.

• MeSH
• buněčná membrána metabolismus   MeSH
• fosfolipidy metabolismus   MeSH
• Heteroptera metabolismus   MeSH
• kyseliny mastné neesterifikované metabolismus   MeSH
• roční období * MeSH
• steroly metabolismus   MeSH
• tokoferoly metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

In a three-year period (2000-2002) total tocols (tocopherols and tocotrienols), content of vitamin E and its isomers (alpha-, beta+gamma-, delta-tocopherols and tocotrienols) were assessed in grain of 13 barley genotypes. The highest content of tocols (60.3-67.6 mg kg(-1)) and content of vitamin E (Vitamin E equivalent-18.0-20.1 mg kg(-1)) were determined in the waxy varieties Wanubet, Wabet, and Washonubet. Standard varieties, i.e. of a malting type (Krona and Kompakt), had statistically significantly lower content of tocols (49.9 and 53.6 mg kg(-1)) and vitamin E (15.7-16.1 mg kg(-1)) compared to the waxy varieties. The hulless waxy variety Washonubet had statistically significantly higher total content of tocols (67.6 mg kg(-1)) and alpha- tocotrienols isomer (42.1 mg kg(-1)) versus all other genotypes in the set. Chemical treatment and fertilization statistically significantly increased the content of tocols (by 4.7 mg kg(-1)), vitamin E (by 1.9 mg kg(-1)), isomer alpha-tocopherol (by 0.9 mg kg(-1)) and isomer alpha- tocotrienols (by 3.3 mg kg(-1)). The average values of alpha-tocopherols and alpha-tocotrienols in the set were 6.7 mg kg(-1) and 29.7 mg kg(-1), respectively. Some of the reciprocal lines created by us from the malting and waxy varieties are suitable for food use for high contents of all tocopherols and alpha-tocotrienols.

• MeSH
• financování organizované MeSH
• geneticky modifikované rostliny MeSH
• genotyp MeSH
• ječmen (rod) genetika   chemie   MeSH
• lidé MeSH
• nutriční hodnota MeSH
• tokoferoly analýza   MeSH
• tokotrienoly analýza   MeSH
• zemědělství metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• srovnávací studie MeSH

A simple and rapid HPLC method requiring small volumes (250 microL) of human serum after C18 SPE sample preparation was developed using monolithic technology for simultaneous determination of all-trans-retinoic acid, 13-cis-retinoic acid, retinol, gamma- and alpha-tocopherol. The monolithic column, Chromolith Performance RP-18e (100x4.6 mm), was operated at ambient temperature. The mobile phase consisted of a mixture of acetonitrile (ACN) and 1% ammonium acetate in water (AMC) at pH 7.0. The mobile phase started at 98:2 (v/v) ACN/AMC (column pre-treatment) at a flow rate of 2 mL/min, then changed to 95:5 (v/v) ACN/AMC for 4 min at a flow rate of 1.5 mL/min and a further 3 min at a flow rate of 3.2 mL/min. Detection and identification were performed using a photodiode array detector. Retinol, 13-cis- and all-trans-retinoic acid were monitored at 325 nm. Both alpha- and gamma-tocopherol were detected at 295 nm. The total analysis time was 7.2 min. Tocol (synthesized tocopherol, not occurring in humans) was used as internal standard. The method was linear in the range of 0.125-10.00 micromol/L for all-trans-retinoic acid, 0.125-5.00 micromol/L for 13-cis-retinoic acid, 0.25-10.00 micromol/L for retinol, 0.5-50.00 micromol/L for gamma-tocopherol, and 0.5-50.00 micromol/L for alpha-tocopherol. The present method may be useful for monitoring of retinoids and tocopherols in clinical studies.

• MeSH
• lidé MeSH
• molekulární struktura MeSH
• nádory krev   terapie   MeSH
• reprodukovatelnost výsledků MeSH
• retinoidy chemie   krev   MeSH
• senzitivita a specificita MeSH
• tokoferoly chemie   krev   MeSH
• vysokoúčinná kapalinová chromatografie metody   přístrojové vybavení   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH

Tokoferol-alfa-acetát nachází uplatnění jako léčivá látka (vitamin E) v perorálních, parenterálních i topických přípravcích. Záměrem článku není dopodrobna rozvádět terapeutické využití tokoferolů, ale podat základní informace o vlastnostech a použití dané látky a především představit příklady vhodných receptur, neboť tokoferol se stále v některých předpisech na individuálně připravované léčivé přípravky objevuje. Příprava může být snazší, protože tokoferol-alfa-acetát je od října 2010 k dispozici lékárnám jako farmaceutická substance pro individuální přípravu léčivých přípravků.

Alpha-tocopherol acetate has been used as medicinal substance (vitamin E) for peroral, parenteral and topical preparationes. The aim of the article is not to present the sometimes questionable therapeutic use of tocopherols but to provide basic information on the properties and use of this substance and to present suitable examples of formulas because tocopherol is still used in some prescriptions of extemporaneous preparations. The formulation can be easier now because alpha-tocopherol acetate has been available as a substance for extemporaneous preparation in pharmacies since October 2010.

• Klíčová slova
• individuální příprava, dithranol, Nasopanthil.,
• MeSH
• alfa-tokoferol farmakologie   škodlivé účinky   terapeutické užití   MeSH
• fixní kombinace léků MeSH
• lékové formy MeSH
• lidé MeSH
• příprava léků metody   MeSH
• tokoferoly aplikace a dávkování   farmakologie   terapeutické užití   MeSH
• Check Tag
• lidé MeSH

A new method has been described for efficient derivatization of secondary alicyclic hydroxyl groups in steroids by alkyl chloroformates (RCFs). Cholesterol, an essential human sterol and a steroid precursor in eukaryotic cells, was used as a model for treatment with various RCFs in an aqueous and non-aqueous environment. While the cholesterol hydroxyl group did not react completely with any of the tested RCFs reagents in the former case, trifluoroethyl chloroformate (TFECF) or heptafluorobutyl chloroformate (HFBCF) fully converts cholesterol and related metabolites into the corresponding mixed carbonates under anhydrous conditions in seconds. The acylation reaction was combined with liquid-liquid microextraction (LLME) between isooctane and acetonitrile phase. The sample preparation requires just a stepwise addition of 50μl isooctane with 5μl of a pyridine catalyst, 100μl acetonitrile and 100μl isooctane with dissolved 5μl of the fluoroalkyl chloroformate reagent to a dried sample. The protocol developed in this study was successfully tested for GC-MS analysis of 12 important model steroids and four main tocopherols. Each analyte provided a single peak with excellent GC separation properties, well defined EI spectra containing diagnostic fragment ions suitable for their identification and quantitation. The new method was further validated for the determination of six diagnostic non-cholesterol sterols and four main tocopherols in human serum and in amniotic fluid. Satisfactory data were obtained in terms of calibration, quantitation limits (for sterols and tocopherols, 0.05 and 0.15μg/ml, respectively), within-run precision (0.9-19.5%) and between-run precision (0.2-19.0%), accuracy (82-115%) and recovery (90-110%). The validated method was successfully applied to GC-MS analysis of the analytes in woman sera and amniotic fluids and the results are well-comparable with those reported by other authors. The presented work demonstrates for the first time capability of the RCFs to derivatize alicyclic hydroxyls in steroids and tocopherols metabolites for GC-MS with excellent reaction rates, highest reaction yields, minor reagent consumption and easy conjunction with LLME methods.

• MeSH
• fluorokarbony chemie   MeSH
• formiáty chemie   MeSH
• indikátory a reagencie MeSH
• lidé MeSH
• mikroextrakce kapalné fáze MeSH
• plodová voda chemie   MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
• sérum MeSH
• steroly analýza   krev   MeSH
• těhotenství MeSH
• tokoferoly analýza   krev   MeSH
• Check Tag
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• validační studie MeSH

Tocopherols, lipid-soluble antioxidants play a crucial role in the antioxidant defense system in higher plants. The antioxidant function of α-tocopherol has been widely studied; however, experimental data on the formation of its oxidation products is missing. In this study, we attempt to provide spectroscopic evidence on the detection of oxidation products of α-tocopherol formed by its interaction with singlet oxygen and lipid peroxyl radical. Singlet oxygen was formed using photosensitizer rose bengal and thylakoid membranes isolated from Arabidopsis thaliana. Singlet oxygen reacts with polyunsaturated fatty acid forming lipid hydroperoxide which is oxidized by ferric iron to lipid peroxyl radical. The addition of singlet oxygen to double bond carbon on the chromanol head of α-tocopherol forms α-tocopherol hydroperoxide detected using fluorescent probe swallow-tailed perylene derivative. The decomposition of α-tocopherol hydroperoxide forms α-tocopherol quinone. The hydrogen abstraction from α-tocopherol by lipid peroxyl radical forms α-tocopheroxyl radical detected by electron paramagnetic resonance. Quantification of lipid and protein hydroperoxide from the wild type and tocopherol deficient (vte1) mutant Arabidopsis leaves using a colorimetric ferrous oxidation-xylenol orange assay reveals that α-tocopherol prevents formation of both lipid and protein hydroperoxides at high light. Identification of oxidation products of α-tocopherol might contribute to a better understanding of the protective role of α-tocopherol in the prevention of oxidative damage in higher plants at high light.

• MeSH
• alfa-tokoferol chemie   metabolismus   MeSH
• antioxidancia chemie   metabolismus   MeSH
• Arabidopsis genetika   růst a vývoj   metabolismus   účinky záření   MeSH
• lipidové peroxidy chemie   metabolismus   MeSH
• oxidace-redukce MeSH
• oxidační stres * MeSH
• peroxid vodíku chemie   metabolismus   MeSH
• singletový kyslík chemie   metabolismus   MeSH
• světlo škodlivé účinky   MeSH
• vitamin E chemie   metabolismus   MeSH
• volné radikály chemie   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• Konspekt
• Lékařské vědy. Lékařství
• NLK Obory
• kardiologie
• patologie
• farmacie a farmakologie
• angiologie
• fyziologie

• MeSH
• alfa-tokoferol analýza   metabolismus   účinky záření   MeSH
• hematopoéza MeSH

Measurement of intestinal permeability represents one of the potential methods of noninvasive laboratory assessment of gastrointestinal toxicity of anticancer therapy. We have assessed intestinal permeability (by measuring absorption of lactulose, mannitol, and xylose), vitamin A absorption and serum alpha-tocopherol in patients with non-small cell lung carcinoma or head and neck carcinomas treated with gefitinib. Lactulose, mannitol and xylose were determined by capillary gas chromatography, and retinol, alpha-tocopherol, retinyl stearate and retinyl palmitate were determined by high-performance liquid chromatography. Compared to healthy controls, patients had significantly increased lactulose/mannitol ratio and lower postprandial retinyl palmitate and retinyl stearate concentrations. Compared with pre-treatment values, xylose absorption was decreased and lactulose/mannitol and lactulose/xylose ratios were increased during the therapy. A significant decrease of serum alpha-tocopherol was evident throughout the course of therapy. In contrast, only minor alterations of vitamin A absorption were observed. In conclusion, an alteration in intestinal permeability reflected in increased lactulose/mannitol and lactulose/xylose ratios was observed during gefitinib therapy. Potential association between decreased serum alpha-tocopherol concentrations and the toxicity of gefitinib therapy should be further investigated.

• MeSH
• alfa-tokoferol krev   MeSH
• chinazoliny farmakologie   terapeutické užití   MeSH
• dospělí MeSH
• intestinální absorpce účinky léků   MeSH
• lidé středního věku MeSH
• lidé MeSH
• permeabilita účinky léků   MeSH
• senioři MeSH
• střeva účinky léků   MeSH
• studie případů a kontrol MeSH
• vitamin A metabolismus   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH