Enhancing the antioxidant effect of α-tocopherol with rosemary in inhibiting catalyzed oxidation caused by Fe and hemoprotein

A mixture of α-tocopherol and rosemary extract (0·035% + 0·035%) was used to inhibit fish lipid oxidation catalyzed by Fe²⁺ or hemoprotein. In a sardine oil model system, a mixture of α-tocopherol and rosemary extract showed a significantly stronger antioxidant effect, as it prolonged the induction period for 10 and 16 days longer than α-tocopherol alone and rosemary extract alone, respectively. In addition, the effective lifetime of α-tocopherol in samples treated with the α-tocopherol and rosemary extract mixture was 10 days longer than in samples with only α-tocopherol added even though the amount of added α-tocopherol in the latter case was twice that for the mixture. In fish dark muscle, the mixture of α-tocopherol and rosemary extract also showed a stronger anti-oxidant effect than either tocopherol or rosemary extract alone. Treatment of samples with this mixture also led to a lower rate of decomposition of highly unsaturated fatty acids, myoglobin and hemoglobin, and triglyceride compared to samples treated with tocopherol or rosemary extract alone.     

The tocopherol pattern in human serum is markedly influenced by intake of vitamin E drugs—Results of the german national health surveys

During national and regional health surveys, done from 1984–1995 in Germany, consumption data for all drugs used by the participants—approximately 18,000 persons—in the last 7 d before the examination were monitored with a detailed drug-usage questionnaire. The groups examined are representative for the national and regional German inhabitant population aged 25–69 yr. In serum samples of subsamples of the study participants, all tocopherols were measured by isocratic high-performance liquid chromatography (Si 60 column, fluorescence detection). Consumption data for tocopherol-containing drugs showed that up to 5% of females and up to 3% of males of the study population used those drugs. During the study period, the serum content of α-tocopherol (mean values ± SD) rose from 7.5 ± 2.6 mg/L serum to 11.8 ± 2.8 mg/L serum for nonusers and from 11.9 ± 4.3 mg/L serum to 15.3 ± 4.9 mg/L serum in tocopherol-drug users. Throughout all studies, it could be shown that β- and γ-tocopherol were heavily reduced in those persons taking daily doses ≥50 mg α-tocopherol. The reduction of the two tocopherols is dose-dependent and especially pronounced in females using high-dose α-tocopherol drugs. Owing to the emerging evidence of the physiological importance concerning the balance of the different tocopherols in biological systems, the possible benefits of using natural tocopherol mixtures from plant origin instead of pure RRR-α-tocopherol, gained from permethylation procedures, as vitamin supplements in human nutrition should be considered.     

α-Tocopherol, β-Carotene and Ascorbic Acid as Antioxidants in Stored Poultry Muscle

Broilers were fed α-tocopherol or β-carotene for 3 wk or L-ascorbic acid for 24 hr prior to slaughter. α-Tocopherol maintained the redness of unheated meat stored for 8 wk (—20°C). Values for thiobarbituric acid reactive substances in ground, stored meat showed that L-ascorbic acid produced results similar to the control while a-tocopherol produced results lower than the control. Panelists rated meat with added α-tocopherol as different from the control for smell and flavor. β-Carotene was a pro-oxidant compared to the control and other additives. Meat from broilers fed β-carotene had lower α-tocopherol content than the control. Vitamin A in livers of birds fed β-carotene was 64% higher than that of the control.     

High efficiency preparation of standard grade γ-tocopherol and its antioxidant activity

Natural standard grade γ-tocopherol is of great interest due to its good antioxidant activity and special pharmacological functions. This study separated and purified γ-tocopherol from mixed tocopherols using eco-friendly and low toxicity solvents. γ-Tocopherol (0.28 g) was obtained per performance with a purity of (98.89 ± 0.68)% and a recovery rate of (93.23 ± 0.89)%. The purification conditions were as follows: elution solvent n-hexane/ethyl acetate 94.5:5.5 (v/v), sample load 0.5 g, a column height to diameter ratio of 16:1 (length and diameter, 60 × 3 cm) and an elution rate of 2 ml/min. The purity and structure of γ-tocopherol was confirmed by high-performance liquid chromatography, gas chromatography/mass spectrometry and nuclear magnetic resonance. The adsorption isotherm of γ-tocopherol on silica gel (200–300 mesh) fitted the Langmuir isotherm model well. The antioxidant activity analysis showed that γ-tocopherol had the strongest antioxidant activity followed by δ-tocopherol and α-tocopherol. This study provides an economically attractive solution for the production of natural standard grade γ-tocopherol.     

Stability of α-Tocopherol, Thiamin, Riboflavin and Retinol in Pork Muscle and Liver during Heating as Affected by Dietary Supplementation

The α-tocopherol (Vit E) and ascorbic acid (Vit C) supplementation of pig diets increased (P<0.05) liver α-tocopherol concentrations. After heating, the liver samples of both treated groups and the longissimus dorsi muscle samples of the vitamin C group showed increased riboflavin retention (P<0.05). The supplemented and control groups did not show differences regarding retention of α-tocopherol, retinol and thiamin in heated liver and longissimus dorsi. Dietary vitamin C resulted in higher liver vitamin E and was most effective in protecting riboflavin against loss during heating of liver or longissimus dorsi.     

��-Tocopherol at Nanomolar Concentration Protects PC12 Cells from Hydrogen Peroxide-Induced Death and Modulates Protein Kinase Activities

The aim of this work was to compare protective and anti-apoptotic effects of α-tocopherol at nanomolar and micromolar concentrations against 0.2 mM H₂O₂-induced toxicity in the PC12 neuronal cell line and to reveal protein kinases that contribute to α-tocopherol protective action. The protection by 100 nM α-tocopherol against H₂O₂-induced PC12 cell death was pronounced if the time of pre-incubation with α-tocopherol was 3–18 h. For the first time, the protective effect of α-tocopherol was shown to depend on its concentration in the nanomolar range (1 nM < 10 nM < 100 nM), if the pre-incubation time was 18 h. Nanomolar and micromolar α-tocopherol decreased the number of PC12 cells in late apoptosis induced by H₂O₂ to the same extent if pre-incubation time was 18 h. Immunoblotting data showed that α-tocopherol markedly diminished the time of maximal activation of extracellular signal-regulated kinase 1/2 (ERK 1/2) and protein kinase B (Akt)-induced in PC12 cells by H₂O₂. Inhibitors of MEK 1/2, PI 3-kinase and protein kinase C (PKC) diminished the protective effect of α-tocopherol against H₂O₂-initiated toxicity if the pre-incubation time was long. The modulation of ERK 1/2, Akt and PKC activities appears to participate in the protection by α-tocopherol against H₂O₂-induced death of PC12 cells. The data obtained suggest that inhibition by α-tocopherol in late stage ERK 1/2 and Akt activation induced by H₂O₂ in PC12 cells makes contribution to its protective effect, while total inhibition of these enzymes is not protective.     

手性液相色谱法直接定量乳粉中RRR-α-生育酚

目的 建立手性液相色谱法直接测定乳粉中RRR-α-生育酚的检测方法.方法 样品经氢氧化钾皂化,石油醚-异丙醚萃取.经小粒径纤维素衍生物型手性柱Daicel Chiralcel OD-3(2.1 mm×150 mm,3μm)直接分离,采用无水乙醇-正己烷(5:995,V:V)(A)和三乙胺-正己烷(5:995,V:V)(...     

国家标准方法在橄榄油α-生育酚含量测定的应用

目的 探究反相高效液相色谱法和正相高效液相色谱法检测橄榄油α－生育酚含量。方法 反相高效液相色谱法采用C30柱, 流动相甲醇/水梯度洗脱,流速为0.8 mL/min, 柱温为20 ℃, 紫外检测波长为 294 nm; 正相高效液相色谱法采用Si120硅胶色谱柱, 流动相为正己烷/1,4二氧六环按(95:5), 流速为 0.8 mL/min, 柱温为30 ℃, 荧光检测激发波长为294 nm, 发射波长为328 nm。结果 反相色谱法测定α-生育酚的线性范围为2.00~60.00 μg/mL, 定量限为0.6 μg/mL, 精密度RSD为5.5, 回收率为90%~105%, RSD为5.5%。正相色谱法测定α-生育酚的线性范围0.200~6.00 μg/mL, 定量限为0.014 μg/mL, 精密度RSD为1.8%, 回收率为99%~103%, RSD为1.2%。结论 正相色谱简便、更快速、更灵敏、更准确, 更适合初榨橄榄油中α-生育酚的定量测定。