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Valerian E. Kagan - One of the best experts on this subject based on the ideXlab platform.

  • structural and dynamic membrane properties of alpha tocopherol and alpha tocotrienol implication to the molecular mechanism of their antioxidant potency
    Biochemistry, 1993
    Co-Authors: Yuichiro J Suzuki, Valerian E. Kagan, Masahiko Tsuchiya, Stephen R Wassall, Yuen M Choo, Girjesh Govil, Lester Packer
    Abstract:

    d-alpha-Tocopherol and d-Alpha-Tocotrienol are two vitamin E constituents having the same aromatic chromanol "head" but different hydrocarbon "tails". Alpha-Tocotrienol has been shown to be more potent in protecting against free radical-induced oxidative stress than alpha-tocopherol. Simple models of phospholipid membrane systems were used to investigate the mechanism of the antioxidant potency of Alpha-Tocotrienol in terms of its effects on membrane order and reorientation dynamics. Chemiluminescence and fluorescence measurements demonstrated that Alpha-Tocotrienol exhibits significantly greater peroxyl radical scavenging potency than alpha-tocopherol in phosphatidylcholine liposomes, whereas both antioxidants have identical activity in hexane. This suggests that the antioxidant potency of Alpha-Tocotrienol requires the membrane environment. When alpha-tocopherol and Alpha-Tocotrienol were examined for their effects on phospholipid molecular order using conventional ESR spin labeling with 5- and 16-position-labeled doxylstearic acid, although both vitamin E constituents disordered the gel phase and stabilized the liquid-crystalline phase, no differences were observed between the effects of the two compounds. A slightly greater increase (19% vs 15%) in ordering of the liquid-crystalline state due to alpha-tocopherol, however, was discerned in noninvasive 2H NMR experiments. The difference is most noticeable near C10-C13 positions of the phospholipid chain, possibly suggesting Alpha-Tocotrienol is located closer to the membrane surface. Saturation-transfer ESR, furthermore, revealed that on the time scale tau c = 10(-7)-10(-3) s the rates of rotation about the long molecular axis and of the wobbling motion of the axis are modified to differing extents by the two forms of the vitamin E.(ABSTRACT TRUNCATED AT 250 WORDS)

  • Palm oil vitamin E protects against ischemia/reperfusion injury in the isolated perfused Langendorff heart
    Nutrition Research, 1992
    Co-Authors: Elena Serbinova, S Khwaja, Judith D. Catudioc, J Ericson, Z Torres, A Gapor, Valerian E. Kagan
    Abstract:

    Abstract We studied the effect of palm oil vitamin E on Langendorff perfused rat hearts subjected to 40 minutes of global ischemia. Our results demonstrated that palm oil vitamin E was more efficient in the protection of isolated Langendorff heart against ischemia/reperfusion injury than tocopherol as measured by its mechanical recovery. Palm oil vitamin E completely suppressed LDH enzyme leakage from ischemic hearts, prevented the decrease in ATP and creatine phosphate levels and inhibited the formation of endogenous lipid peroxidation products. Our data indicate that a palm oil vitamin E mixture containing both alpha-tocopherol and Alpha-Tocotrienol may be more efficient than alpha-tocopherol alone in the protection of the heart against oxidative stress induced by ischemia-reperfusion.

  • palm oil vitamin e protects against ischemia reperfusion injury in the isolated perfused langendorff heart
    Nutrition Research, 1992
    Co-Authors: Elena Serbinova, S Khwaja, Judith D. Catudioc, J Ericson, Z Torres, A Gapor, Valerian E. Kagan
    Abstract:

    Abstract We studied the effect of palm oil vitamin E on Langendorff perfused rat hearts subjected to 40 minutes of global ischemia. Our results demonstrated that palm oil vitamin E was more efficient in the protection of isolated Langendorff heart against ischemia/reperfusion injury than tocopherol as measured by its mechanical recovery. Palm oil vitamin E completely suppressed LDH enzyme leakage from ischemic hearts, prevented the decrease in ATP and creatine phosphate levels and inhibited the formation of endogenous lipid peroxidation products. Our data indicate that a palm oil vitamin E mixture containing both alpha-tocopherol and Alpha-Tocotrienol may be more efficient than alpha-tocopherol alone in the protection of the heart against oxidative stress induced by ischemia-reperfusion.

  • free radical recycling and intramembrane mobility in the antioxidant properties of alpha tocopherol and alpha tocotrienol
    Free Radical Biology and Medicine, 1991
    Co-Authors: Elena Serbinova, Valerian E. Kagan, Lester Packer
    Abstract:

    d-Alpha-tocopherol (2R, 4′R,8′R-Alpha-tocopherol) and d-Alpha-Tocotrienol are two main vitamin E constituents having the same aromatic chromanol “head” but differing in their hydrocarbon “tail”: tocopherol with a saturated and toctrienol with an unsaturated isoprenoid chain. d-Alpha-tocopherol has the highest vitamin E activity, while d-Alpha-Tocotrienol manifests only about 30% of this activity. Since vitamin E is considered to be physiologically the most important lipid-soluble chain-breaking antioxidant of membranes, we studied Alpha-Tocotrienol as compared to alpha-tocopherol under conditions which are important for their antioxidant function. d-Alpha-Tocotrienol possesses 40–60 times higher antioxidant activity against (Fe2+ + ascorbate)- and (Fe2+ + NADPH)-induced lipid peroxidation in rat liver microsomal membranes and 6.5 times better protection of cytochrome P-450 against oxidative damage than d-alpha-tocopherol. To clarify the mechanisms responsible for the much higher antioxidant potency of d-Alpha-Tocotrienol compared to d-alpha-tocopherol, ESR studies were performed of recycling efficiency of the chromanols from their chromanoxyl radicals, 1H-NMR measurements of lipid molecular mobility in liposomes containing chromanols, and fluorescence measurements which reveal the uniformity of distribution (clusterizations) of chromanols in the lipid bilayer. From the results, we concluded that this higher antioxidant potency of d-Alpha-Tocotrienol is due to the combined effects of three properties exhibited by d-Alpha-Tocotrienol as compared to d-alpha-tocopherol: (i) its higher recycling efficiency from chromanoxyl radicals, (ii) its more uniform distribution in membraned bilayer, and (iii) its stronger disordering of membrane lipids which makes interaction of chromanols with lipid radicals more efficient. The data presented show that there is a considerable discrepancy between the relative in vitro antioxidant activity of d-Alpha-Tocotrienol with the conventional bioassays of their vitamin activity.

Elena Serbinova - One of the best experts on this subject based on the ideXlab platform.

  • Antioxidant properties of alpha-tocopherol and Alpha-Tocotrienol.
    Methods in enzymology, 1994
    Co-Authors: Elena Serbinova, Lester Packer
    Abstract:

    Publisher Summary This chapter describes the antioxidant properties of α-tocopherol and α-tocotrienol. Tocopherols and tocotrienols are present in various components of the human diet. Tocopherols are found in polyunsaturated vegetable oils and in the germ of cereal seeds, whereas tocotrienols are found in the aleurone and subaleurone layers of cereal seeds and in palm oil. Although the tocopherols and tocotrienols are closely related chemically, they have widely varying degrees of biological effectiveness. The potency of α-tocotrienol evaluated by gestation-resorption assays are 32% of the potency of α-tocopherol. The chapter discusses the relative and the absolute antioxidant effectiveness in vitro of the individual tocopherols that make up vitamin E. It is recognized that differences in vivo in the antioxidant activity of tocopherols and tocotrienols may depend greatly on their pharmacokinetics. However, α-tocotrienol may have higher antioxidant activity in vivo under conditions of oxidative stress because of its more effective antioxidant potency in membranes.

  • Palm oil vitamin E protects against ischemia/reperfusion injury in the isolated perfused Langendorff heart
    Nutrition Research, 1992
    Co-Authors: Elena Serbinova, S Khwaja, Judith D. Catudioc, J Ericson, Z Torres, A Gapor, Valerian E. Kagan
    Abstract:

    Abstract We studied the effect of palm oil vitamin E on Langendorff perfused rat hearts subjected to 40 minutes of global ischemia. Our results demonstrated that palm oil vitamin E was more efficient in the protection of isolated Langendorff heart against ischemia/reperfusion injury than tocopherol as measured by its mechanical recovery. Palm oil vitamin E completely suppressed LDH enzyme leakage from ischemic hearts, prevented the decrease in ATP and creatine phosphate levels and inhibited the formation of endogenous lipid peroxidation products. Our data indicate that a palm oil vitamin E mixture containing both alpha-tocopherol and Alpha-Tocotrienol may be more efficient than alpha-tocopherol alone in the protection of the heart against oxidative stress induced by ischemia-reperfusion.

  • palm oil vitamin e protects against ischemia reperfusion injury in the isolated perfused langendorff heart
    Nutrition Research, 1992
    Co-Authors: Elena Serbinova, S Khwaja, Judith D. Catudioc, J Ericson, Z Torres, A Gapor, Valerian E. Kagan
    Abstract:

    Abstract We studied the effect of palm oil vitamin E on Langendorff perfused rat hearts subjected to 40 minutes of global ischemia. Our results demonstrated that palm oil vitamin E was more efficient in the protection of isolated Langendorff heart against ischemia/reperfusion injury than tocopherol as measured by its mechanical recovery. Palm oil vitamin E completely suppressed LDH enzyme leakage from ischemic hearts, prevented the decrease in ATP and creatine phosphate levels and inhibited the formation of endogenous lipid peroxidation products. Our data indicate that a palm oil vitamin E mixture containing both alpha-tocopherol and Alpha-Tocotrienol may be more efficient than alpha-tocopherol alone in the protection of the heart against oxidative stress induced by ischemia-reperfusion.

  • free radical recycling and intramembrane mobility in the antioxidant properties of alpha tocopherol and alpha tocotrienol
    Free Radical Biology and Medicine, 1991
    Co-Authors: Elena Serbinova, Valerian E. Kagan, Lester Packer
    Abstract:

    d-Alpha-tocopherol (2R, 4′R,8′R-Alpha-tocopherol) and d-Alpha-Tocotrienol are two main vitamin E constituents having the same aromatic chromanol “head” but differing in their hydrocarbon “tail”: tocopherol with a saturated and toctrienol with an unsaturated isoprenoid chain. d-Alpha-tocopherol has the highest vitamin E activity, while d-Alpha-Tocotrienol manifests only about 30% of this activity. Since vitamin E is considered to be physiologically the most important lipid-soluble chain-breaking antioxidant of membranes, we studied Alpha-Tocotrienol as compared to alpha-tocopherol under conditions which are important for their antioxidant function. d-Alpha-Tocotrienol possesses 40–60 times higher antioxidant activity against (Fe2+ + ascorbate)- and (Fe2+ + NADPH)-induced lipid peroxidation in rat liver microsomal membranes and 6.5 times better protection of cytochrome P-450 against oxidative damage than d-alpha-tocopherol. To clarify the mechanisms responsible for the much higher antioxidant potency of d-Alpha-Tocotrienol compared to d-alpha-tocopherol, ESR studies were performed of recycling efficiency of the chromanols from their chromanoxyl radicals, 1H-NMR measurements of lipid molecular mobility in liposomes containing chromanols, and fluorescence measurements which reveal the uniformity of distribution (clusterizations) of chromanols in the lipid bilayer. From the results, we concluded that this higher antioxidant potency of d-Alpha-Tocotrienol is due to the combined effects of three properties exhibited by d-Alpha-Tocotrienol as compared to d-alpha-tocopherol: (i) its higher recycling efficiency from chromanoxyl radicals, (ii) its more uniform distribution in membraned bilayer, and (iii) its stronger disordering of membrane lipids which makes interaction of chromanols with lipid radicals more efficient. The data presented show that there is a considerable discrepancy between the relative in vitro antioxidant activity of d-Alpha-Tocotrienol with the conventional bioassays of their vitamin activity.

Lester Packer - One of the best experts on this subject based on the ideXlab platform.

  • topical α tocotrienol supplementation inhibits lipid peroxidation but fails to mitigate increased transepidermal water loss after benzoyl peroxide treatment of human skin
    Free Radical Biology and Medicine, 2003
    Co-Authors: Stefan Weber, Jens J Thiele, Nancy Han, Chate Luu, Giuseppe Valacchi, Stefanie Weber, Lester Packer
    Abstract:

    Benzoyl peroxide (BPO) is a commonly used drug in the treatment of acne vulgaris, but it induces unwanted side effects related to stratum corneum (SC) function. Since it has been recently shown to oxidize SC antioxidants, it was hypothesized that antioxidant supplementation may mitigate the BPO-induced SC changes. To test this, 11 subjects were selected to be topically supplemented with Alpha-Tocotrienol (5% w/vol) for 7 d on defined regions of the upper back, while the contralateral region was used for vehicle-only controls. Starting on day 8, all test sites were also treated with BPO (10%) for 7 d; the Alpha-Tocotrienol supplementation was continued throughout the study. A single dose of BPO depleted 93.2% of the total vitamin E. While continuing the BPO exposure for 7 d further depleted vitamin E in both vehicle-only and Alpha-Tocotrienol-treated sites, significantly more vitamin E remained in the Alpha-Tocotrienol-treated areas. Seven BPO applications increased lipid peroxidation. Alpha-Tocotrienol supplementation significantly mitigated the BPO-induced lipid peroxidation. The transepidermal water loss was increased 1.9-fold by seven BPO applications, while there was no difference between Alpha-Tocotrienol treatment and controls. The data suggest that Alpha-Tocotrienol supplementation counteracts the lipid peroxidation but not the barrier perturbation in the SC induced by 10% BPO.

  • Simultaneous determination of tissue tocopherols, tocotrienols, ubiquinols, and ubiquinones
    Journal of lipid research, 1996
    Co-Authors: Maurizio Podda, Maret G Traber, Christine Weber, Lester Packer
    Abstract:

    A tissue-specific distribution of the various vitamin E forms, tocotrienols and tocopherols, has been found, suggesting that these forms have unique roles in cellular functions. A sensitive procedure is described for the simultaneous determination of individual tocopherols, tocotrienols, ubiquinols, and ubiquinones using gradient high pressure liquid chromatography (HPLC) and electrochemical detection for vitamin E homologues and ubiquinols, and in-line UV detection for ubiquinones. Using this method, the lipophilic antioxidant complement of a variety of hairless mouse tissues was analyzed. Of the vitamin E forms, brain contained virtually only alpha-tocopherol (5.4 +/- 0.1 nmol/g; 99.8%) and no detectable tocotrienols were found. By contrast, skin contained nearly 15% tocotrienols and 1% gamma-tocopherol. In other tissues, the alpha-tocopherol content was higher (20 nmol/g), while each of the other forms represented about 1% of the total (gamma-tocopherol 0.2 to 0.4 nmol/g, Alpha-Tocotrienol 0.1, gamma-tocotrienol 0.2). Ubiquinol-9 concentrations were highest in kidney (81 nmol/g) and in liver (42 nmol/g), while the highest ubiquinone-9 concentrations were found in kidney (301 +/- 123 nmol/g) and heart (244 +/- 22 nmol/g). Liver contained nearly identical concentrations of each of the redox couple (ubiquinol-9 (41 +/- 16 nmol/g) and ubiquinone-9 (46 +/- 18 nmol/g). The unique distribution of these various antioxidants in the tissues measured suggests their distribution may be dependent upon selective mechanisms for maintaining antioxidant defenses in each tissue.

  • Antioxidant properties of alpha-tocopherol and Alpha-Tocotrienol.
    Methods in enzymology, 1994
    Co-Authors: Elena Serbinova, Lester Packer
    Abstract:

    Publisher Summary This chapter describes the antioxidant properties of α-tocopherol and α-tocotrienol. Tocopherols and tocotrienols are present in various components of the human diet. Tocopherols are found in polyunsaturated vegetable oils and in the germ of cereal seeds, whereas tocotrienols are found in the aleurone and subaleurone layers of cereal seeds and in palm oil. Although the tocopherols and tocotrienols are closely related chemically, they have widely varying degrees of biological effectiveness. The potency of α-tocotrienol evaluated by gestation-resorption assays are 32% of the potency of α-tocopherol. The chapter discusses the relative and the absolute antioxidant effectiveness in vitro of the individual tocopherols that make up vitamin E. It is recognized that differences in vivo in the antioxidant activity of tocopherols and tocotrienols may depend greatly on their pharmacokinetics. However, α-tocotrienol may have higher antioxidant activity in vivo under conditions of oxidative stress because of its more effective antioxidant potency in membranes.

  • structural and dynamic membrane properties of alpha tocopherol and alpha tocotrienol implication to the molecular mechanism of their antioxidant potency
    Biochemistry, 1993
    Co-Authors: Yuichiro J Suzuki, Valerian E. Kagan, Masahiko Tsuchiya, Stephen R Wassall, Yuen M Choo, Girjesh Govil, Lester Packer
    Abstract:

    d-alpha-Tocopherol and d-Alpha-Tocotrienol are two vitamin E constituents having the same aromatic chromanol "head" but different hydrocarbon "tails". Alpha-Tocotrienol has been shown to be more potent in protecting against free radical-induced oxidative stress than alpha-tocopherol. Simple models of phospholipid membrane systems were used to investigate the mechanism of the antioxidant potency of Alpha-Tocotrienol in terms of its effects on membrane order and reorientation dynamics. Chemiluminescence and fluorescence measurements demonstrated that Alpha-Tocotrienol exhibits significantly greater peroxyl radical scavenging potency than alpha-tocopherol in phosphatidylcholine liposomes, whereas both antioxidants have identical activity in hexane. This suggests that the antioxidant potency of Alpha-Tocotrienol requires the membrane environment. When alpha-tocopherol and Alpha-Tocotrienol were examined for their effects on phospholipid molecular order using conventional ESR spin labeling with 5- and 16-position-labeled doxylstearic acid, although both vitamin E constituents disordered the gel phase and stabilized the liquid-crystalline phase, no differences were observed between the effects of the two compounds. A slightly greater increase (19% vs 15%) in ordering of the liquid-crystalline state due to alpha-tocopherol, however, was discerned in noninvasive 2H NMR experiments. The difference is most noticeable near C10-C13 positions of the phospholipid chain, possibly suggesting Alpha-Tocotrienol is located closer to the membrane surface. Saturation-transfer ESR, furthermore, revealed that on the time scale tau c = 10(-7)-10(-3) s the rates of rotation about the long molecular axis and of the wobbling motion of the axis are modified to differing extents by the two forms of the vitamin E.(ABSTRACT TRUNCATED AT 250 WORDS)

  • free radical recycling and intramembrane mobility in the antioxidant properties of alpha tocopherol and alpha tocotrienol
    Free Radical Biology and Medicine, 1991
    Co-Authors: Elena Serbinova, Valerian E. Kagan, Lester Packer
    Abstract:

    d-Alpha-tocopherol (2R, 4′R,8′R-Alpha-tocopherol) and d-Alpha-Tocotrienol are two main vitamin E constituents having the same aromatic chromanol “head” but differing in their hydrocarbon “tail”: tocopherol with a saturated and toctrienol with an unsaturated isoprenoid chain. d-Alpha-tocopherol has the highest vitamin E activity, while d-Alpha-Tocotrienol manifests only about 30% of this activity. Since vitamin E is considered to be physiologically the most important lipid-soluble chain-breaking antioxidant of membranes, we studied Alpha-Tocotrienol as compared to alpha-tocopherol under conditions which are important for their antioxidant function. d-Alpha-Tocotrienol possesses 40–60 times higher antioxidant activity against (Fe2+ + ascorbate)- and (Fe2+ + NADPH)-induced lipid peroxidation in rat liver microsomal membranes and 6.5 times better protection of cytochrome P-450 against oxidative damage than d-alpha-tocopherol. To clarify the mechanisms responsible for the much higher antioxidant potency of d-Alpha-Tocotrienol compared to d-alpha-tocopherol, ESR studies were performed of recycling efficiency of the chromanols from their chromanoxyl radicals, 1H-NMR measurements of lipid molecular mobility in liposomes containing chromanols, and fluorescence measurements which reveal the uniformity of distribution (clusterizations) of chromanols in the lipid bilayer. From the results, we concluded that this higher antioxidant potency of d-Alpha-Tocotrienol is due to the combined effects of three properties exhibited by d-Alpha-Tocotrienol as compared to d-alpha-tocopherol: (i) its higher recycling efficiency from chromanoxyl radicals, (ii) its more uniform distribution in membraned bilayer, and (iii) its stronger disordering of membrane lipids which makes interaction of chromanols with lipid radicals more efficient. The data presented show that there is a considerable discrepancy between the relative in vitro antioxidant activity of d-Alpha-Tocotrienol with the conventional bioassays of their vitamin activity.

A Gapor - One of the best experts on this subject based on the ideXlab platform.

  • Vitamin E inhibition of normal mammary epithelial cell growth is associated with a reduction in protein kinase Cα activation
    Cell proliferation, 2001
    Co-Authors: Paul W. Sylvester, A Gapor, Barry S. Mcintyre, Karen P. Briski
    Abstract:

    Tocopherols and tocotrienols represent the two subclasses within the vitamin E family of compounds. However, tocotrienols are significantly more potent than tocopherols in suppressing epidermal growth factor (EGF)-dependent normal mammary epithelial cell growth. EGF is a potent mitogen for normal mammary epithelial cells and an initial event in EGF-receptor mitogenic-signalling is protein kinase C (PKC) activation. Studies were conducted to determine if the antiproliferative effects of specific tocopherol and tocotrienol isoforms are associated with a reduction in EGF-receptor mitogenic signalling and/or PKC activation. Normal mammary epithelial cells isolated from midpregnant BALB/c mice were grown in primary culture, and maintained on serum-free media containing 10 ng/mL EGF as a mitogen, and treated with various doses (0-250 microm) of alpha-, gamma-, or delta-tocopherol or alpha-, gamma-, or delta-tocotrienol. Treatment with growth inhibitory doses of delta-tocopherol (100 microm), Alpha-Tocotrienol (50 microm), or gamma- or delta-tocotrienol (10 microm) did not affect EGF-receptor levels, EGF-induced EGF-receptor tyrosine kinase activity, or total intracellular levels of PKC(alpha). However, these treatments were found to inhibit EGF-induced PKC(alpha) activation as determined by its translocation from the cytosolic to membrane fraction. Treatment with 250 microm alpha- or gamma-tocopherol had no affect on EGF-receptor mitogenic signalling or cell growth. These findings demonstrate that the inhibitory effects of specific tocopherol and tocotrienol isoforms on EGF-dependent normal mammary epithelial cell mitogenesis occurs downstream from the EGF-receptor and appears to be mediated, at least in part, by a reduction in PKC(alpha) activation.

  • Dietary α-Tocopherol Attenuates the Impact of γ-Tocotrienol on Hepatic 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase Activity in Chickens
    The Journal of nutrition, 1996
    Co-Authors: Asaf A. Qureshi, A Gapor, Bradley C. Pearce, Rosnah M. Nor, David M. Peterson, Charles E. Elson
    Abstract:

    The concentration-dependent impact of gamma-tocotrienol on serum cholesterol can be traced to the posttranscriptional down-regulation of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity. gamma-Tocotrienol also suppresses tumor growth. Palmvitee, the tocopherol and tocotrienol-rich fraction of palm oil, is the sole commercial source of gamma-tocotrienol. Contrary to the universal findings of the efficacy of gamma-tocotrienol there are conflicting reports of the impact of Palmvitee on 3-hydroxy-3-methylglutaryl coenzyme A reductase activity, serum cholesterol concentrations and tumor development. These conflicting reports led us to examine the impact of alpha-tocopherol on the cholesterol-suppressive action of gamma-tocotrienol. Control and experimental diets were fed to groups of White Leghorn chickens (n = 10) for 26 d. The control diet was supplemented with 21 nmol alpha-tocopherol/g. All experimental diets provided 141 nmol of blended tocols/g diet. The alpha-tocopherol and gamma-tocotrienol concentrations of the experimental diets ranged from 21 to 141 and 0 to 120 nmol/g, respectively. We now report that including alpha-tocopherol in tocol blends containing adequate gamma-tocotrienol to suppress 3-hydroxy-3-methylglutaryl coenzyme A reductase activity results in an attenuation of the tocotrienol action (P or = 30% alpha-tocopherol and 45% gamma- (and delta-) tocotrienol.

  • Palm oil vitamin E protects against ischemia/reperfusion injury in the isolated perfused Langendorff heart
    Nutrition Research, 1992
    Co-Authors: Elena Serbinova, S Khwaja, Judith D. Catudioc, J Ericson, Z Torres, A Gapor, Valerian E. Kagan
    Abstract:

    Abstract We studied the effect of palm oil vitamin E on Langendorff perfused rat hearts subjected to 40 minutes of global ischemia. Our results demonstrated that palm oil vitamin E was more efficient in the protection of isolated Langendorff heart against ischemia/reperfusion injury than tocopherol as measured by its mechanical recovery. Palm oil vitamin E completely suppressed LDH enzyme leakage from ischemic hearts, prevented the decrease in ATP and creatine phosphate levels and inhibited the formation of endogenous lipid peroxidation products. Our data indicate that a palm oil vitamin E mixture containing both alpha-tocopherol and Alpha-Tocotrienol may be more efficient than alpha-tocopherol alone in the protection of the heart against oxidative stress induced by ischemia-reperfusion.

  • palm oil vitamin e protects against ischemia reperfusion injury in the isolated perfused langendorff heart
    Nutrition Research, 1992
    Co-Authors: Elena Serbinova, S Khwaja, Judith D. Catudioc, J Ericson, Z Torres, A Gapor, Valerian E. Kagan
    Abstract:

    Abstract We studied the effect of palm oil vitamin E on Langendorff perfused rat hearts subjected to 40 minutes of global ischemia. Our results demonstrated that palm oil vitamin E was more efficient in the protection of isolated Langendorff heart against ischemia/reperfusion injury than tocopherol as measured by its mechanical recovery. Palm oil vitamin E completely suppressed LDH enzyme leakage from ischemic hearts, prevented the decrease in ATP and creatine phosphate levels and inhibited the formation of endogenous lipid peroxidation products. Our data indicate that a palm oil vitamin E mixture containing both alpha-tocopherol and Alpha-Tocotrienol may be more efficient than alpha-tocopherol alone in the protection of the heart against oxidative stress induced by ischemia-reperfusion.

Kalyana Sundram - One of the best experts on this subject based on the ideXlab platform.

  • Alpha-Tocotrienol is the most abundant tocotrienol isomer circulated in plasma and lipoproteins after postprandial tocotrienol-rich vitamin E supplementation
    Nutrition Journal, 2012
    Co-Authors: Syed Fairus, Rosnah M. Nor, Hwee M Cheng, Kalyana Sundram
    Abstract:

    Background Tocotrienols (T3) and tocopherols (T), both members of the natural vitamin E family have unique biological functions in humans. T3 are detected in circulating human plasma and lipoproteins, although at concentrations significantly lower than α-tocopherol (α-T). T3, especially α-T3 is known to be neuropotective at nanomolar concentrations and this study evaluated the postprandial fate of T3 and α-T in plasma and lipoproteins. Methods Ten healthy volunteers (5 males and 5 females) were administered a single dose of vitamin E [526 mg palm tocotrienol-rich fraction (TRF) or 537 mg α-T] after 7-d pre-conditioning on a T3-free diet. Blood was sampled at baseline (fasted) and 2, 4, 5, 6, 8, and 24 h after supplementation. Concentrations of T and T3 isomers in plasma, triacylglycerol-rich particles (TRP), LDL, and HDL were measured at each postprandial interval. Results After TRF supplementation, plasma α-T3 and γ-T3 peaked at 5 h (α-T3: 4.74 ± 1.69 μM; γ-T3: 2.73 ± 1.27 μM). δ-T3 peaked earlier at 4 h (0.53 ± 0.25 μM). In contrast, α-T peaked at 6 h (30.13 ± 2.91 μM) and 8 h (37.80 ± 3.59 μM) following supplementation with TRF and α-T, respectively. α-T was the major vitamin E isomer detected in plasma, TRP, LDL, and HDL even after supplementation with TRF (composed of 70% T3). No T3 were detected during fasted states. T3 are detected postprandially only after TRF supplementation and concentrations were significantly lower than α-T. Conclusions Bio-discrimination between vitamin E isomers in humans reduces the rate of T3 absorption and affects their incorporation into lipoproteins. Although low absorption of T3 into circulation may impact some of their physiological functions in humans, T3 have biological functions well below concentration noted in this study.

  • Alpha-Tocotrienol is the most abundant tocotrienol isomer circulated in plasma and lipoproteins after postprandial tocotrienol-rich vitamin E supplementation.
    Nutrition journal, 2012
    Co-Authors: Syed Fairus, Rosnah M. Nor, Hwee M Cheng, Kalyana Sundram
    Abstract:

    Tocotrienols (T3) and tocopherols (T), both members of the natural vitamin E family have unique biological functions in humans. T3 are detected in circulating human plasma and lipoproteins, although at concentrations significantly lower than α-tocopherol (α-T). T3, especially α-T3 is known to be neuropotective at nanomolar concentrations and this study evaluated the postprandial fate of T3 and α-T in plasma and lipoproteins. Ten healthy volunteers (5 males and 5 females) were administered a single dose of vitamin E [526 mg palm tocotrienol-rich fraction (TRF) or 537 mg α-T] after 7-d pre-conditioning on a T3-free diet. Blood was sampled at baseline (fasted) and 2, 4, 5, 6, 8, and 24 h after supplementation. Concentrations of T and T3 isomers in plasma, triacylglycerol-rich particles (TRP), LDL, and HDL were measured at each postprandial interval. After TRF supplementation, plasma α-T3 and γ-T3 peaked at 5 h (α-T3: 4.74 ± 1.69 μM; γ-T3: 2.73 ± 1.27 μM). δ-T3 peaked earlier at 4 h (0.53 ± 0.25 μM). In contrast, α-T peaked at 6 h (30.13 ± 2.91 μM) and 8 h (37.80 ± 3.59 μM) following supplementation with TRF and α-T, respectively. α-T was the major vitamin E isomer detected in plasma, TRP, LDL, and HDL even after supplementation with TRF (composed of 70% T3). No T3 were detected during fasted states. T3 are detected postprandially only after TRF supplementation and concentrations were significantly lower than α-T. Bio-discrimination between vitamin E isomers in humans reduces the rate of T3 absorption and affects their incorporation into lipoproteins. Although low absorption of T3 into circulation may impact some of their physiological functions in humans, T3 have biological functions well below concentration noted in this study.