Tocopherol Research Articles

Lutein and zeaxanthin uptake in cultured retinal pigmented epithelial cells.

The retinal pigment epithelium (RPE) has the essent ial role of providing oxygen and nutrients to the photoreceptors but also to removes their deb ris and metabolites. The RPE is subject to continuo usly and high level of oxidative stress. RPE use endogenous enzymatic and non-enzymatic antioxidants as a mechanism of reactive oxygen species (ROS) detoxification. RP E is also particularly rich in non-enzymatic antiox idants such are tocopherols, ascorbic acid, lutein and zea xanthin. In this study we investigated the ability of RPE cu ltured cells to incorporate lutein and zeaxanthin, in free and esterified forms, the carotenoid effect on cell culture viability and on cell antioxidant defense. Carotenoids were delivered to the cell culture using small amou nts of tetrahydrofuran added to the fetal calf seru m. The incorporation yield was determined by UV-Vis spectrophotometry, the cells viability by MTT assay and t he antioxidant effect by intracellular ROS assay (DCF- DA). Human RPE cultured cells can incorporate the major dietary carotenoids, lutein and zeaxanthin. The highest incorporation yield was found for zeaxanthi n, with 8.1 % of incorporation yield, while lutein incorporation yield was 7.12 %. Esterified xanthop hylls can not be incorporated into RPE cells. Lutei n and zeaxanthin administrated to RPE cells does not sign ificantly influence the cell viability. They showed a small positive effect on the cell viability in a concentr ation of 10 �M in the culture media. Lutein and zeaxanthin have an inhibitory effect on reactive oxygen species gen eration in the RPE cells.

STUDY CONCERNING PROTEINS EXTRACTION PROCESS FROM PEAS IN DIFFERENT WORK CONDITIONS

Peas represent a valuable source of vegetal proteins, quantitatively and qualitatively. Dry peas contain 24.5% proteins which contain all essential amino-acids, having an excess of lysine, still being short in methionine. Proteins are represented by globulin and legumelin, are easy soluble, having high digestibility. Carbohydrates are represented by starch but also by saccharose, in proportion of 5-10%. The amount of lipids is small, but there are in great amounts lecithin. Peas also contain vitamins represented by tocopherols, vitamins from B group and various mineral substances. For protein extraction from any biologic material, the material must be preliminarily fine powdered after what the actually extraction is made by treatment with solvents that can be water, salts solutions, mixture of water-ethanol, or diluted solutions of acids or bases. In order to intensify the extraction process normally is lurched to the mechanical stirring of the mixture, expanding in this way the substance transfer according to Fick’s law. It has been certificated that by applying an ultrasound field in the extraction process, greatly increases the substance transfer and implicitly the extraction speed. This is due the acoustic cavitation phenomenon which appears in a liquid exposed in an ultrasound field with sufficient intensity. The acoustic cavitation is manifested by forming cavitational bubbles which in the first phase are increasing their volume and after that they suddenly implode creating a powerful shock wave which is propagated in the solution. Due this shock waves in which the pressure can reach 10000 atmospheres, the cellular walls are destroyed and the cellular content passes in the external medium. Also due the acoustic cavitation, in solution appear powerful current which mixes the solution components. In the current work the comparative extraction with water and NaOH diluted solution was used by mechanical stirring and by ultrasound field exposure, respectively. The extracted proteins proportion is higher by using the extraction in an ultrasound field. Also, from the two solvents used it is noticed that by using the NaOH solution a better effective power of extraction was obtained comparative with the distilled water case. So, by using the assisted extraction of ultrasounds, by using as a solvent the NaOH solution, the maximal proportion of proteins was extracted, that is, approximately 96% of total proteins from peas, according to data concerning the composition of the peas flour extracted from bibliography

Influence of sn‐1,3‐lipase‐catalysed interesterification on the oxidative stability of soybean oil‐based structured lipids

AbstractThe oxidative stability of structured lipids (SLs) synthesised by specific sn‐1,3‐lipase catalysed interesterification of soybean oil (SBO) with caprylic acid (CA) in a stirred batch reactor was studied. SLs contained considerable amounts of tocopherol (TOH) isomers, although they lost almost 25% of endogenous TOHs during production. The effects of the addition of different TOH homologues (α, β, γ, δ), ascorbyl palmitate (AP, 200 ppm), lecithin (Le, 1000 ppm), butylated hydroxytoluene (BHT, 100 ppm) and butylated hydroxyanisole (BHA, 100 ppm) on the oxidative stability of SLs were investigated. Induction time (IT) of SBO, determined by the Rancimat method, decreased from 8.4 to 5.8 h at 110 °C after the modification. On the other hand, purified SLs and purified SBO had the same IT due to the tocopherol reduction during silica purification. No significant difference was observed between IT of SLs and SLs plus different α‐tocopherol concentrations (50, 100, 150, 200, 300, 500 and 1000 ppm) (P > 0.05). However, the addition of Le and/or AP significantly improved oxidative stability of purified SLs and SBO. The ternary blend containing δ‐TOH, AP and Le had higher IT than ternary blends of α‐TOH, β‐TOH or γ‐TOH. Furthermore, ternary blend containing BHA, AP and Le had higher IT than ternary blends of BHT, AP and Le. In addition, there was an increase in peroxide value (PV), conjugated diene (CD) content and p‐anisidine value (AV) during oxidation of oils at 60 °C. Antioxidant mixtures of α‐TOH (50 ppm) and δ‐TOH (500 ppm) with AP and Le decreased PV, CD and AV effectively. Copyright © 2006 Society of Chemical Industry

Natural vitamin E α-tocotrienol: Retention in vital organs in response to long-term oral supplementation and withdrawal

The natural vitamin E tocotrienol (TCT) possesses biological properties not shared by tocopherols (TCP). Nanomolar α-TCT, not α-TCP, is potently neuroprotective (JBC 275:13049; 278:43508; Stroke 36:2258). The report that the affinity of TTP to bind α-TCT is an order of magnitude lower than that for α-TCP questions the bioavailability of orally taken TCT to tissues. Oral supplementation of TCT for 3 years in nine generations of female and male rat was studied. Ten vital organs were examined. To gain insight into the turnover of α-TCT in tissues, a subset of supplemented rats was moved to vitamin E deficient diet for 7 weeks. Orally supplemented α-TCT was delivered to all vital organs including the brain and spinal cord in significant amounts. In organs such as the skin, adipose and gonads the maximum level of α-TCT achieved in response to supplementation was folds higher than baseline values of α-TCP in rats maintained on laboratory chow. Females had higher levels of α-TCT compared to matched tissues of corresponding males. To gain insight into how quickly α-TCT is metabolized in the tissues, washout of α-TCT from vital organs was examined. α-TCT accumulated in vital organs over more than 2 years was almost completely lost in less than 2 months when the supplementation was stopped. This is in sharp contrast with findings related to α-TCP retention. The ability of long term oral supplementation to maintain and elevate α-TCT levels in vital organs together with the rapid elimination of the intact vitamin from all organs studied underscores the need for continuous oral supplementation of TCT.

Delivery of orally supplemented α-tocotrienol to vital organs of rats and tocopherol-transport protein deficient mice

The natural vitamin E tocotrienol (TCT) possesses biological properties not shared by tocopherols (TCP). Nanomolar α-TCT, not α-TCP, is potently neuroprotective (JBC 275:13049; 278:43508). Tocopherol-transport protein (TTP) represents the primary mechanism for maintaining normal α-TCP concentrations in plasma and extrahepatic tissues. TTP primarily transports α-TCP and has low affinity for α-TCT. There are no studies that have investigated tissue delivery of α-TCT when orally gavaged on a long-term basis. A long-term study was conducted to examine the effects of α-TCT or α-TCP supplementation, either alone or in combination, on tissue levels. Rats were maintained on a vitamin E-deficient diet and gavaged with α-TCT or α-TCP alone or in combination. Five generations of rats were studied over 60 weeks. TTP-deficient mice were supplemented with TCT and bred to examine tissue delivery of oral α-TCT. Orally supplemented α-TCT was effectively delivered to most tissues over time. When co-supplemented, α-TCP outcompeted α-TCT for transport systems delivering vitamin E to tissues. To evaluate the significance of TTP in α-TCT delivery to tissues, tissue levels of α-TCT in supplemented TTP-deficient mice were studied. α-TCT was transported to several vital organs in TTP-deficient mice. α-TCT restored fertility in TTP-deficient mice. In sum, orally supplemented α-TCT was successfully delivered to several vital organs. The transport efficiency of α-TCT to tissues may be maximized by eliminating the co-presence of α-TCP in the oral supplement. Examination of whether α-TCT may benefit humans suffering from neurological disorders because of congenital TTP deficiency is warranted.

Effect of oxygen plasma treatment on the release behaviors of poly(ɛ-caprolactone) microcapsules containing tocopherol

The biodegradable poly(ɛ-caprolactone) microcapsules (PCL) containing tocopherol (TC) were prepared by emulsion solvent evaporation method, and microcapsules were treated by oxygen plasma to enhance the hydrophilic microcapsules. The morphologies and thermal properties of the microcapsules were determined by SEM and DSC measurements. The microcapsules studied were characterized by surface free energy or work of adhesion through contact angle measurement. As a result, the features of the microcapsules could be adjusted by manufacturing condition, such as surfactant and core ratio. The surface free energy or work of adhesion of the microcapsules was increased with increasing the time of plasma treatment, which could be attributed to the increased hydrophilic groups during oxygen plasma treatment. The release profile of the microcapsules was determined by UV–vis spectroscopy and the microcapsules containing tocopherol showed the rapid release rate, as compared with untreated ones.

A tocopherol a day keeps ALS at bay?

A tocopherol a day keeps ALS at bay?

Rapid assay of vitamin E in vegetable oils by reversed-phase capillary electrochromatography.

A rapid capillary electrochromatographic (CEC) method for the analysis of vitamin E in vegetable oils is reported. Vitamin E consists of a group of eight isomers, tocopherols (TOHs) and tocotrienols. The separation of four TOHs (alpha-, gamma-, delta-TOH), alpha-tocopherol acetate (alpha-TOH-Ac), and an antioxidant compound, butylated hydroxytoluene (BHT) used to prevent TOH autoxidation, was optimized. The CEC experiments were carried out in a 75 microm inner diameter (ID) fused-silica capillary, partially packed with 3 microm C(18 )stationary phase (33 cm total length, 8.4 cm and 7 cm effective and packed lengths, respectively). The optimum mobile phase was a polar organic phase composed of a mixture of methanol-acetonitrile in the ratio 50/50 v/v containing 0.01% ammonium acetate, applying a voltage and temperature set at -25 kV and 20 degrees C, respectively. The tocopherols and the BHT were successfully separated within 2.5 min using the short-end injection method. Under these experimental conditions, repeatability of retention time and peak area, analyte detection and quantitation limits, linearity, precision, and accuracy were studied. The CEC method was applied to determine the content of TOHs in different commercially available oils of virgin olive, hazelnut, sunflower, and soybean. The extraction of vitamin E isomers from oil samples was achieved using methanol and a methanol-isopropanol mixture.

Registration of CR‐34 and CR‐81 Safflower Germplasms with Increased Tocopherol

Registration of CR‐34 and CR‐81 Safflower Germplasms with Increased Tocopherol

The Effect of Photofrin on DNA Strand Breaks and Base Oxidation in HaCaT Keratinocytes: A Comet Assay Study¶

Photodynamic therapy (PDT) kills cells via the production of singlet oxygen and other reactive oxygen species. PDT causes chromosomal damage and mutation to cultured cells. However, DNA damage does not contribute to the phototoxic effect. To study the effect of Photofrin-PDT-induced DNA damage, we used the comet assay in combination with endonuclease III and formamidopyrimidine DNA glycosylase and a human keratinocyte cell line to investigate photogenotoxicity and its prevention by tocopherol (TOC). This study shows that PDT induced DNA damage in HaCaT cells at doses allowing cells to survive 7 days after irradiation. alpha-TOC did not prevent the acute cell lysis caused by Photofrin-PDT but did prevent Photofrin-PDT-induced DNA damage. However, the concentration of TOC that conferred protection (100 microM) was higher than is detected in human serum. Base oxidation was also measured using the comet assay. Although TOC could prevent frank DNA strand breaks caused by PDT, it was unable to decrease the level of base oxidation as revealed by enzyme-sensitive sites. It is suggested that the potential genotoxic risk from laser-PDT could be low, and that topical micro-TOC at a high concentration may be useful in preventing some types of DNA damage without preventing acute photolysis after Photofrin-PDT.

The Effect of Photofrin on DNA Strand Breaks and Base Oxidation in HaCaT Keratinocytes: A Comet Assay Study¶

ABSTRACTPhotodynamic therapy (PDT) kills cells via the production of singlet oxygen and other reactive oxygen species. PDT causes chromosomal damage and mutation to cultured cells. However, DNA damage does not contribute to the phototoxic effect. To study the effect of Photofrin‐PDT‐induced DNA damage, we used the comet assay in combination with endonuclease III and formamidopyrimidine DNA glycosylase and a human keratinocyte cell line to investigate photogenotoxicity and its prevention by tocopherol (TOC). This study shows that PDT induced DNA damage in HaCaT cells at doses allowing cells to survive 7 days after irradiation. α‐TOC did not prevent the acute cell lysis caused by Photofrin‐PDT but did prevent Photofrin‐PDT‐induced DNA damage. However, the concentration of TOC that conferred protection (100 μM) was higher than is detected in human serum. Base oxidation was also measured using the comet assay. Although TOC could prevent frank DNA strand breaks caused by PDT, it was unable to decrease the level of base oxidation as revealed by enzymesensitive sites. It is suggested that the potential genotoxic risk from laser‐PDT could be low, and that topical α‐TOC at a high concentration may be useful in preventing some types of DNA damage without preventing acute photolysis after Photofrin‐PDT.

Time course for antioxidants production by Antrodia camphorata in submerged culture

The mycelia of Antrodia camphorata (Chang & Chou) Wu, Ryvarden & Chang were grown in a 50-ton fermentor for 18 days. The antioxidant properties and antioxidant components of methanolic extracts from mycelia at different days of incubation were studied. In the antioxidant activity by the conjugated diene method, EC50 value of mycelia at day 18 (1.46 mg/mL) was the best, followed by values of mycelia at days 10, 13 and 16. Reducing powers were good (＞ 0.64) at concentrations of methanolic extracts higher than 2.5 mg/mL and EC50 values were considerately low (0.40–0.53 mg/mL) for mycelia at days 7 to 16. At 0.5 mg/mL, the scavenging effect on 1,1-diphenyl-2-picrylhydrazyl radicals was excellent (93.2.93.9%) and EC50 values were extremely low (0.27 mg/mL) for mycelia at days 7 to 16. The chelating effects on ferrous ions were good (58.9.92.3%) at 2.5 to 10 mg/mL. Contents of naturally occurring antioxidant components were found in the order of total phenols ＞ tocopherols ＞ ascorbic acid ＞ β-carotene. Methanolic extracts from A. camphorata red mycelia in submerged culture were good in the antioxidant properties tested, except for the scavenging effect on hydroxyl ions. More specifically, the antioxidant properties were good for mycelia at days 10 to 16.

Donepezil + tocopherol beneficial in AD

Donepezil + tocopherol beneficial in AD

Maternal and posthatch dietary polyunsaturated fatty acids alter tissue tocopherol status of chicks

The effects of maternal and starter diet polyunsaturated fatty acid (PUFA) composition on the tocopherol (TOC) status of posthatch chicks were investigated. Fertile eggs enriched with long chain n-3, 18:3 n-3 or 18:2 n-6 PUFA were incubated. The eggs were collected from hens fed diets containing 3.5% menhaden oil (MO), linseed oil (LO), or sunflower oil (SO) and a vitamin E mix containing 400 microg/g total TOC. Posthatch chicks from MO, LO, or SO were fed starter diets containing 3.5% MO, LO, or SO along with vitamin E mix containing 48 microg/g total TOC. Tissues (liver, blood, brain) were collected on d 0 (day of hatch), 7, 14, and 21 posthatch. On d 0, MO chicks had the lowest liver and plasma TOC (P < 0.05). A rapid depletion of liver and plasma TOC was observed on d 7 and 14 posthatch (P < 0.001) and was lower in MO chicks (P < 0.05) than LO. When compared with d 0, a 98% decrease of tocopherol on d 7 was observed for chicks from all treatments. No changes due to age or diet PUFA was observed in the brain TOC status. Data showed that maternal and starter diet PUFA could alter the TOC status of chicks in early life.

Flavonoids from the Aquatic Plant Eriocaulon buergerianum

AbstractFor Abstract see ChemInform Abstract in Full Text.

Inhibition of Alcohol-Associated Colonic Hyperregeneration by ??-Tocopherol in the Rat

Inhibition of Alcohol-Associated Colonic Hyperregeneration by ??-Tocopherol in the Rat

THERMAL STABILITY OF SOME COMMERCIAL NATURAL AND SYNTHETIC ANTIOXIDANTS AND THEIR MIXTURES

ABSTRACT The thermal stability of some commercially available antioxidants alone or in binary or ternary mixtures was investigated in order to find the optimal combination of antioxidants for food processing. The synthetic antioxidants used were butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), propyl gallate (PG) and tertiary‐butyhydroquinone (TBHQ). Other antioxidants such as ascorbyl palmitate (AP), mixed tocopherols (TOCO) and monoacylglycerol citrate (MGC) were also employed. The effectiveness of these antioxidants and their combinations was assessed using the Rancimat test by measuring the induction period for the oxidation of sunflower oil after heating at 180C for 1 h and comparing it to the oxidation kinetics of the oil without added antioxidants. All antioxidants and their binary or ternary mixtures showed different degrees of thermal instability. TBHQ individually, among all the examined antioxidants, showed the highest thermal stability. On the other hand, AP as an antioxidant in sunflower oil exhibited low stability during heating. The thermal stability of AP could be enhanced by the addtion of BHA or BHT in binary mixtures at a ratio of 1:3 (w/w). In addition, the ternary mixture of AP, TOCO and MGC (65:25:10) in sunflower oil also showed a higher stability to thermal inactivation. However, the ternary mixture containing 0.13% AP, 0.05% TBHQ and 0.02% MGC provided the optimal protection during thermal treatment. Although a combination of 0.13% BHT, 0.05% AP and 0.02% MG was very effective synergistically at room temperature, it showed a higher susceptibility to thermal inactivation. It was

Flavonoids from the aquatic plant Eriocaulon buergerianum

Four flavonoids including (2 S)-3′,4′-methylenedioxy-5,7-dimethoxyflavan and hispidulin 7-(6- E- p-coumaroyl-β- d-glucopyranoside), and one tocopherol were isolated from the capitulum of Eriocaulon buergerianum KOERN. Their structures were established by spectral and chemical evidence.

Tocopherol beneficial in hypercholesterolaemia

Tocopherol beneficial in hypercholesterolaemia

Management of Oxidative Stress by Heme Oxygenase-1 in Cisplatin-induced Toxicity in Renal Tubular Cells

Induction of heme oxygenase-1 (HO-1) may serve as an immediate protective response during treatment with the cytostatic drug cisplatin (CDDP). Oxidative pathways participate in the characteristic nephrotoxicity of CDDP. In the present study, cultured tubular cells (LLC-PK1) were used to investigate whether induction of HO provided protection against CDDP by maintaining the cellular redox balance. The antioxidants, f -tocopherol (TOCO) and N -acetylcysteine (NAC), were used to demonstrate that elevation of ROS levels contribute to the development of CDDP-induced cytotoxicity. Chemical modulators of HO activity were used to investigate the role of HO herein. Hemin was used to specifically induce HO-1, while exposure of the cells to tin-protoporphyrin (SnPP) was shown to inhibit HO activity. Hemin treatment prior to CDDP-exposure significantly decreased the generation of ROS to control levels, while inhibition of HO increased the ROS levels beyond the levels measured in cells treated with CDDP alone. Furthermore, HO induction protected significantly against the cytotoxicity of CDDP, although this protection was limited. Similar results were obtained when the cells were preincubated with TOCO, suggesting that mechanisms other than impairment of the redox ratio are important in CDDP-induced loss of cell viability in vitro. In addition, SnPP treatment exacerbated the oxidative response and cytotoxicity of CDDP, especially at low CDDP concentrations. We therefore conclude that HO is able to directly limit the CDDP-induced oxidative stress response and thus serves as safeguard of the cellular redox balance.