Displaying publications 1 - 20 of 79 in total

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  1. Fulltext The effect of increased consumption of edible palm oil on the nutritional status, lipid profiles and lipid peroxidation among Malaysian aborigines
    Iskandar Zulkarnain Alias, Zaleha Md. Isa, Osman Ali, Khalid Abdul Kadir
    Malays J Nutr, 2002;8(2):137-156.
    MyJurnal
    This study was conducted to determine the effects of increased edible palm oil consumption on community health status in the aboriginal communities in Tual Post (treatment group) and Sinderut Post (control group), Kuala Lipis, Pahang. Nutritional status, blood pressure, lipid profiles, fasting blood glucose (FBG), vitamin E (alpha-tocopherol) levels and lipid peroxidation product (malonaldehyde) levels were taken as indicators of health status. This is a pre-and post-controlled community trial in which similar variables were measured in each group. Every family of 2–6 household members was given 2–5 kg cooking palm oil per month for a period of 18 months. All subjects were measured for height (cm), weight (kg) and waist-hip ratio (WHR). For calorie intake measurement, house-to-house interviews were conducted using 24-hour dietary recall method. Blood pressure, percent body fat, lipid profiles, namely total cholesterol, high density lipoprotein cholesterol, triglyceride and fasting blood glucose (FBG) were also measured. Vitamin E (alpha-tocopherol) levels and lipid peroxidation products (MDA) were also determined. There was a significant increase (p
    Matched MeSH terms: alpha-Tocopherol
  2. Fulltext Dose-dependent cholesterolemic activity of tocotrienols and α-tocopherol
    Khor, Hun Teik, Ng, Theng Theng, Rajendran, Raajeswari
    Malays J Nutr, 2002;8(2):157-166.
    MyJurnal
    Tocotrienols and tocopherols are isoforms of vitamin E. Vitamin E may exhibit antioxidant, prooxidant and non-antioxidant activities depending upon circumstances. In this study, the effect of tocotrienols and α-tocopherol on the activities of HMG CoA reductase and cholesterol 7 α-hydroxylase was investigated. Pure tocotrienols were isolated from palm fatty acid distillate and pure α-tocopherol was obtained commercially. Guinea pigs were treated with different dosages of tocotrienols and α-tocopherol. After the treatment period, animals were sacrificed and liver microsomes were prepared. HMG CoA reductase and cholesterol 7α-hydroxylase were assayed using tracer techniques. Our results showed that the effects of tocotrienols and α-tocopherol on the activities of both the enzymes were dose-dependent. At low dosages, both tocotrienols and α-tocopherol exhibited an inhibitory effect on both the enzymes. Moreover, tocotrienols were a much stronger inhibitors than α-tocopherol. At high dosages, on the other hand, tocotrienols and α-tocopherol showed opposite effects on the enzymes. While tocotrienols continued to exhibit an inhibitory effect, α-tocopherol actually exhibited a stimulatory effect on both the enzymes. A possible explanation for this observation is suggested.
    Matched MeSH terms: alpha-Tocopherol
  3. Fulltext Vitamin E deficiency reduced lumbar bone calcium content in female rats
    Norazlina M, Chua CW, Ima-Nirwana S
    Med J Malaysia, 2004 Dec;59(5):623-30.
    PMID: 15889565
    Vitamin E deficiency has been found to impair bone calcification. This study was done to determine the effects of vitamin E deficiency and supplementation on parathyroid hormone, i.e. the hormone involved in bone regulation. Female Sprague-Dawley rats were divided into 4 groups: 1) normal rat chow (RC), 2) vitamin E deficiency (VED), vitamin E deficient rats supplemented with 3) 60 mg/kg alpha-tocotrienol (ATT) and 4) 60 mg/kg (alpha-tocopherol (ATF). Treatment was carried out for 3 months. Vitamin E deficiency caused hypocalcaemia during the first month of the treatment period, increased the parathyroid hormone level in the second month and decreased the bone calcium content in the 4th lumbar bone at the end of the treatment. Vitamin E supplementation (ATT and ATF) failed to improve these conditions. The bone formation marker, osteocalcin, and the bone resorption marker, deoxypyridinoline did not change throughout the study period. In conclusion vitamin E deficiency impaired bone calcium homeostasis with subsequent secondary hyperparathyroidism and vertebral bone loss. Replacing the vitamin E with pure ATF or pure ATT alone failed to correct the changes seen.
    Matched MeSH terms: alpha-Tocopherol/therapeutic use*
  4. Determination of total antioxidant activity in three types of local vegetables shoots and the cytotoxic effect of their ethanolic extracts against different cancer cell lines
    Rahmat A, Kumar V, Fong LM, Endrini S, Sani HA
    Asia Pac J Clin Nutr, 2004;13(3):308-11.
    PMID: 15331345
    Antioxidants play an important role in inhibiting and scavenging radicals, thus providing protection to humans against infections and degenerative diseases. Literature shows that the antioxidant activity is high on herbal and vegetable plants. Realizing the fact, this research was carried out to determine total antioxidant activity and the potential anticancer properties in three types of selected local vegetable shoots such as Diplazium esculentum (paku shoot), Manihot utillissima (tapioca shoot) and Sauropous androgynus (cekur manis). The research was also done to determine the effect of boiling, on total antioxidant activity whereby samples of fresh shoots are compared with samples of boiled shoots. In every case, antioxidant activity is compared to alpha-tocopherol and two methods of extraction used are the organic and the aqueous methods. Besides that, two research methods used were the ferric thiocyanate (FTC) and thiobarbituric acid (TBA) with absorbance of 500nm and 532nm respectively. Oneway ANOVA test at P<0.05 determines significant differences between various samples. In the cytotoxic study, the ethanolic extract and several cell lines i.e. breast cancer (MDA-MB-231 and MCF-7), colon cancer (Caco-2), liver cancer (HepG2) and normal liver (Chang liver) were used. The IC(50)-value was determined by using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. The antioxidant study found that all the samples in both aqueous and organic extraction were significantly different. The total antioxidant activity values of aqueous extract in descending order are as follows: M. utilissima (fresh) >D. esculentum (fresh) >S.androgynus (fresh) > M.utilissima (boiled) > D. esculentum (boiled) > S.androgynus (boiled). It also was found that S.androgynus shoots ethanolic extract was able to inhibit the viability of the breast cancer cell lines, MDA-MB-231 with the IC50 value of 53.33 micrograms/ml. However, S.androgynus shoots and D. esculentum shoots ethanolic extracts did not inhibit the viability of MDA-MB-231 cell line. While, the tapioca shoot ethanolic extract was able to inhibit the viability of MCF-7 cell line with the IC(50) value of 52.49 micrograms/ml. S.androgynus shoots and D.esculentum shoots ethanolic extracts did not give an IC(50) value against the MCF-7 cell line. S.androgynus, tapioca and D.esculentum shoots ethanolic extracts did not show cytotoxic effect against the Caco-2 and HepG2. There was no IC(50)-value from any sample against Chang Liver cell line. In conclusion, the antioxidant activity of both fresh and boiled samples were higher than alpha-tocopherol, although fresh vegetable shoots were found to be higher in antioxidant activity compared to boiled shoots. This study also suggested that S.androgynus shoots and tapioca shoots have potential as an anticancer agent against certain breast tumours.
    Matched MeSH terms: alpha-Tocopherol/pharmacology
  5. Effects of tocopherols and tocotrienols on body composition and bone calcium content in adrenalectomized rats replaced with dexamethasone
    Ima-Nirwana S, Suhaniza S
    J Med Food, 2004;7(1):45-51.
    PMID: 15117552
    Long-term glucocorticoid treatment is associated with severe side effects, such as obesity and osteoporosis. A palm oil-derived vitamin E mixture had been shown previously to be protective against osteoporosis in rats given 120 microg/kg dexamethasone daily for 12 weeks. In this study we determined the effects of two isomers of vitamin E (i.e., palm oil-derived gamma-tocotrienol and the commercially available alpha-tocopherol, 60 mg/kg of body weight/day) on body composition and bone calcium content in adrenalectomized rats replaced with two doses of dexamethasone, 120 microg/kg and 240 microg/kg daily. Treatment period was 8 weeks. gamma-Tocotrienol (60 mg/kg of body weight/day) was found to reduce body fat mass and increase the fourth lumbar vertebra bone calcium content in these rats, while alpha-tocopherol (60 mg/kg of body weight/day) was ineffective. Therefore, in conclusion, palm oil-derived gamma-tocotrienol has the potential to be utilized as a prophylactic agent in prevention of the side effects of long-term glucocorticoid use.
    Matched MeSH terms: alpha-Tocopherol/pharmacology
  6. Antioxidant, radical-scavenging, anti-inflammatory, cytotoxic and antibacterial activities of methanolic extracts of some Hedyotis species
    Ahmad R, Ali AM, Israf DA, Ismail NH, Shaari K, Lajis NH
    Life Sci, 2005 Mar 11;76(17):1953-64.
    PMID: 15707878
    The antioxidant, radical-scavenging, anti-inflammatory, cytotoxic and antibacterial activities of methanolic extracts of seven Hedyotisspecies were investigated. The antioxidant activity was evaluated by the ferric thiocyanate (FTC) and thiobarbituric acid (TBA) methods while the radical scavenging activity was measured by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. The anti-inflammatory activity related to NO inhibition of the plant extracts was measured by the Griess assay while cytotoxicity were measured by the MTT assay against CEM-SS cell line. The antibacterial bioassay (against 4 bacteria, i.e. Bacillus subtilis B28 (mutant), Bacillus subtilis B29 (wild-type), Pseudomonas aeruginosa UI 60690 and methicillin resistant Staphylococcus aureus, (MRSA) was also carried out using the disc-diffusion method. All tested extracts exhibited very strong antioxidant properties when compared to Vitamin E (alpha-tocopherol) with percent inhibition of 89-98% in the FTC and 60-95% in the TBA assays. In the DPPH method, H. herbacea exhibited the strongest radical scavenging activity with an IC50 value of 32 microg/ml. The results from the Griess assay showed that the tested extracts are weak inhibitors of NO synthase. However, all tested extracts exhibited moderate cytotoxic properties against CEM-SS cell line giving CD50 values in the range of 21-41 microg/ml. In the antibacterial bioassay, the stems and the roots of H. capitellata showed moderate activity against the 4 tested bacteria while the leaves showed moderate activity towards B. subtilis B28, MRSA and P. aeruginosa only. The roots of H. dichotoma showed strong antibacterial activity against all 4 bacteria. All other extracts did not exhibit any antibacterial activity.
    Matched MeSH terms: alpha-Tocopherol/pharmacology
  7. Comparative effects of palm vitamin E and alpha-tocopherol on healing and wound tissue antioxidant enzyme levels in diabetic rats
    Musalmah M, Nizrana MY, Fairuz AH, NoorAini AH, Azian AL, Gapor MT, et al.
    Lipids, 2005 Jun;40(6):575-80.
    PMID: 16149736
    The effect of supplementing 200 mg/kg body weight palm vitamin E (PVE) and 200 mg/kg body weight alpha-tocopherol (alpha-Toc) on the healing of wounds in streptozotocin-induced diabetic rats was evaluated. The antioxidant potencies of these two preparations of vitamin E were also evaluated by determining the antioxidant enzyme activities, namely, glutathione peroxidase (GPx) and superoxide dismutase (SOD), and malondialdehyde (MDA) levels in the healing of dermal wounds. Healing was evaluated by measuring wound contractions and protein contents in the healing wounds. Cellular redistribution and collagen deposition were assessed morphologically using cross-sections of paraffin-embedded day-10 wounds stained according to the Van Gieson method. GPx and SOD activities as well as MDA levels were determined in homogenates of day-10 dermal wounds. Results showed that PVE had a greater potency to enhance wound repair and induce the increase in free radical-scavenging enzyme activities than alpha-Toc. Both PVE and alpha-Toc, however, were potent antioxidants and significantly reduced the lipid peroxidation levels in the wounds as measured by the reduction in MDA levels.
    Matched MeSH terms: alpha-Tocopherol/pharmacology*
  8. Tocotrienol offers better protection than tocopherol from free radical-induced damage of rat bone
    Ahmad NS, Khalid BA, Luke DA, Ima Nirwana S
    Clin Exp Pharmacol Physiol, 2005 Sep;32(9):761-70.
    PMID: 16173934
    1. Free radicals generated by ferric nitrilotriacetate (FeNTA) can activate osteoclastic activity and this is associated with elevation of the bone resorbing cytokines interleukin (IL)-1 and IL-6. In the present study, we investigated the effects of 2 mg/kg FeNTA (2 mg iron/kg) on the levels of serum IL-1 and IL-6 with or without supplementation with a palm oil tocotrienol mixture or alpha-tocopherol acetate in Wistar rats. 2. The FeNTA was found to elevate levels of IL-1 and IL-6. Only the palm oil tocotrienol mixture at doses of 60 and 100 mg/kg was able to prevent FeNTA-induced increases in IL-1 (P < 0.01). Both the palm oil tocotrienol mixture and alpha-tocopherol acetate, at doses of 30, 60 and 100 mg/kg, were able to reduce FeNTA-induced increases in IL-6 (P < 0.05). Therefore, the palm oil tocotrienol mixture was better than pure alpha-tocopherol acetate in protecting bone against FeNTA (free radical)-induced elevation of bone-resorbing cytokines. 3. Supplementation with the palm oil tocotrienol mixture or alpha-tocopherol acetate at 100 mg/kg restored the reduction in serum osteocalcin levels due to ageing, as seen in the saline (control) group (P < 0.05). All doses of the palm oil tocotrienol mixture decreased urine deoxypyridinoline cross-link (DPD) significantly compared with the control group, whereas a trend for decreased urine DPD was only seen for doses of 60 mg/kg onwards of alpha-tocopherol acetate (P < 0.05). 4. Bone histomorphometric analyses have shown that FeNTA injections significantly lowered mean osteoblast number (P < 0.001) and the bone formation rate (P < 0.001), but raised osteoclast number (P < 0.05) and the ratio of eroded surface/bone surface (P < 0.001) compared with the saline (control) group. Supplementation with 100 mg/kg palm oil tocotrienol mixture was able to prevent all these FeNTA-induced changes, but a similar dose of alpha-tocopherol acetate was found to be effective only for mean osteoclast number. Injections of FeNTA were also shown to reduce trabecular bone volume (P < 0.001) and trabecular thickness (P < 0.05), whereas only supplementation with 100 mg/kg palm oil tocotrienol mixture was able to prevent these FeNTA-induced changes.
    Matched MeSH terms: alpha-Tocopherol/analogs & derivatives*; alpha-Tocopherol/pharmacology
  9. Comparative effects of alpha-tocopherol and gamma-tocotrienol against hydrogen peroxide induced apoptosis on primary-cultured astrocytes
    Mazlan M, Sue Mian T, Mat Top G, Zurinah Wan Ngah W
    J Neurol Sci, 2006 Apr 15;243(1-2):5-12.
    PMID: 16442562
    Oxidative stress is thought to be one of the factors that cause neurodegeneration and that this can be inhibited by antioxidants. Since astrocytes support the survival of central nervous system (CNS) neurons, we compared the effect of alpha-tocopherol and gamma-tocotrienol in minimizing the cytotoxic damage induced by H(2)O(2), a pro-oxidant. Primary astrocyte cultures were pretreated with either alpha-tocopherol or gamma-tocotrienol for 1 h before incubation with 100 microM H(2)O(2) for 24 h. Cell viability was then assessed using the MTS assay while apoptosis was determined using a commercial ELISA kit as well as by fluorescent staining of live and apoptotic cells. The uptake of alpha-tocopherol and gamma-tocotrienol by astrocytes were also determined using HPLC. Results showed that gamma-tocotrienol is toxic at concentrations >200 microM but protects against H(2)O(2) induced cell loss and apoptosis in a dose dependent manner up to 100 microM. alpha-Tocopherol was not cytotoxic in the concentration range tested (up to 750 microM), reduced apoptosis to the same degree as that of gamma-tocotrienol but was less effective in maintaining the viable cell number. Since the uptake of alpha-tocopherol and gamma-tocotrienol by astrocytes is similar, this may reflect the roles of these 2 vitamin E subfamilies in inhibiting apoptosis and stimulating proliferation in astrocytes.
    Matched MeSH terms: alpha-Tocopherol/metabolism; alpha-Tocopherol/therapeutic use; alpha-Tocopherol/toxicity*
  10. Postprandial metabolic fate of tocotrienol-rich vitamin E differs significantly from that of alpha-tocopherol
    Fairus S, Nor RM, Cheng HM, Sundram K
    Am J Clin Nutr, 2006 Oct;84(4):835-42.
    PMID: 17023711
    BACKGROUND: The detection of tocotrienols in human plasma has proven elusive, and it is hypothesized that they are rapidly assimilated and redistributed in various mammalian tissues.

    OBJECTIVE: The primary study objective was to evaluate the postprandial fate of tocotrienols and alpha-tocopherol in human plasma and lipoproteins.

    DESIGN: Seven healthy volunteers (4 males, 3 females) were administered a single dose of vitamin E [1011 mg palm tocotrienol-rich fraction (TRF) or 1074 mg alpha-tocopherol] after a 7-d conditioning period with a tocotrienol-free diet. Blood was sampled at baseline (fasted) and 2, 4, 5, 6, 8, and 24 h after supplementation. Concentrations of tocopherol and tocotrienol isomers in plasma, triacylglycerol-rich particles (TRPs), LDLs, and HDLs were measured at each interval.

    RESULTS: After intervention with TRF, plasma tocotrienols peaked at 4 h (4.79 +/- 1.2 microg/mL), whereas alpha-tocopherol peaked at 6 h (13.46 +/- 1.68 microg/mL). Although tocotrienols were similarly detected in TRPs, LDLs, and HDLs, tocotrienol concentrations were significantly lower than alpha-tocopherol concentrations. In comparison, plasma alpha-tocopherol peaked at 8 h (24.3 +/- 5.22 microg/mL) during the alpha-tocopherol treatment and emerged as the major vitamin E isomer detected in plasma and lipoproteins during both the TRF and the alpha-tocopherol treatments.

    CONCLUSIONS: Tocotrienols are detected in postprandial plasma, albeit in significantly lower concentrations than is alpha-tocopherol. This finding confirms previous observations that, in the fasted state, tocotrienols are not detected in plasma. Tocotrienol transport in lipoproteins appears to follow complex biochemically mediated pathways within the lipoprotein cascade.

    Matched MeSH terms: alpha-Tocopherol/blood*
  11. Fulltext Effects of vitamin E supplementation on bone metabolism in nicotine-treated rats
    Norazlina M, Lee PL, Lukman HI, Nazrun AS, Ima-Nirwana S
    Singapore Med J, 2007 Mar;48(3):195-9.
    PMID: 17342286
    Nicotine has been shown to exert negative effects on bone. This study determined whether vitamin E supplementation is able to repair the nicotine-induced adverse effects in bone.
    Matched MeSH terms: alpha-Tocopherol/pharmacology*
  12. Fulltext Palm tocotrienol exerted better antioxidant activities in bone than alpha-tocopherol
    Maniam S, Mohamed N, Shuid AN, Soelaiman IN
    Basic Clin Pharmacol Toxicol, 2008 Jul;103(1):55-60.
    PMID: 18598299 DOI: 10.1111/j.1742-7843.2008.00241.x
    The aim of this study was to investigate the effects of vitamin E on the levels of lipid peroxidation and antioxidant enzymes in rat bones. Fifty-six normal male Sprague-Dawley rats, aged 3 months, were randomly divided into seven groups with eight rats in each group. The age-matched control group was given the vehicle olive oil, by oral gavage daily. Six of the treatment groups received either palm tocotrienol or pure alpha-tocopherol at the dose of 30, 60 or 100 mg/kg body weight, by oral gavage daily, 6 days a week for 4 months. Thiobarbituric acid-reactive substance (TBARS) that is an index to measure the level of lipid peroxidation and the antioxidant enzymes, glutathione peroxidase and superoxide dismutase levels were measured in the femur at the end of the study. Palm tocotrienol at the dose of 100 mg/kg body weight significantly reduced the TBARS level in the femur with a significant increase in glutathione peroxidase activity compared to the age-matched control group. These were not observed in the alpha-tocopherol groups. Palm tocotrienol was more effective than pure alpha-tocopherol acetate in suppressing lipid peroxidation in bone. Palm tocotrienol showed better protective effect against free radical damage in the femur compared to alpha-tocopherol. This study suggests that palm tocotrienol plays an important role in preventing imbalance in bone metabolism due to free radicals.
    Matched MeSH terms: alpha-Tocopherol/administration & dosage; alpha-Tocopherol/pharmacology*
  13. Fulltext Tocotrienol and alpha-tocopherol reduce corticosterone and noradrenalin levels in rats exposed to restraint stress
    Nur Azlina MF, Nafeeza MI
    Pharmazie, 2008 Dec;63(12):890-2.
    PMID: 19177905
    This study investigates the effects of tocotrienol (TT) or alpha-tocopherol (TF) supplementation on corticosterone level, noradrenalin level and gastric lesions in rats exposed to restraint stress. Twenty-four male Sprague Dawley rats were randomly assigned into 4 equally sized groups; two control groups were given olive oil, while the treated group was supplemented with either tocotrienol of tocopherol orally at a dose of 60 mg/kg body weight. After 28 days of treatment, one control group, TT group and TF group were subjected to restraint stress, 2 hours daily for 4 consecutive days. After the last exposure to stress, plasma samples were taken to determine the corticosterone and noradrenalin levels, after which the rats were sacrificed. The stomach was excised for the evaluation of gastric lesions. Our findings showed that TT and TF were able to maintain the corticosterone level to the prestress values, while only TT was able to maintain the noradrenalin level in rats exposed to stress. Tocotrienol was found to be better in preventing formation of gastric lesions compared to TF. As a conclusion, the protective effect of vitamin E was related to the ability to inhibit stress induced elevation of corticosterone and noradrenalin levels.
    Matched MeSH terms: alpha-Tocopherol/pharmacology*
  14. Fulltext Effects of Palm Tocotrienols on Oxidative Stress and Bone Strength in Ovariectomised Rats
    Nazrun, A.S., Khairunnur, A., Norliza, M., Norazlina, M., Iman Nirwana, S.
    Medicine & Health, 2008;3(2):247-255.
    MyJurnal
    Oxidative stress has been associated with postmenopausal osteoporosis which pre-disposes to risk of fracture. Palm tocotrienol is a potent antioxidant and has the poten-tial to be used for treatment of post-menopausal osteoporosis. The aim of the study is to determine if palm tocotrienol supplementation could alleviate oxidative stress in ovariectomised rat model and improve its bone strength. The rats were di- vided into four groups: (i) sham-operated  group (SHAM) (ii) ovariectomised-control group (OVX) (iii) ovariectomised and given 60mg/kg α-tocopherol by oral gavage (OVX + ATF) (iv) ovariectomised and given 60mg/kg palm tocotrienols by oral gavage (OVX + PTT). After eight weeks of treatment, blood samples were taken to measure oxida-tive status (MDA, SOD and GPX) while the femurs were biomechanically tested for strength and resistance to fracture. Ovariectomy was shown to induce oxidative stress as shown by the raised MDA levels and reduced GPX activity. Palm tocotrienols seemed to offer protection against the ovariectomy-induced oxidative stress as shown by the suppression of MDA levels and raised GPX and SOD activities in the OVX+PTT group. In comparison, α-tocopherol was only able to raise the SOD but not as high as palm tocotrienols. The biomechanical tests have shown that ovariectomy has not af-fected the bone strength significantly after eight weeks. Palm tocotrienols supplemen-tation for eight weeks was effective in preventing oxidative stress in a post-meno-pausal rat.
    Matched MeSH terms: alpha-Tocopherol
  15. Fulltext Daily supplementation of tocotrienol-rich fraction or alpha-tocopherol did not induce immunomodulatory changes in healthy human volunteers
    Radhakrishnan AK, Lee AL, Wong PF, Kaur J, Aung H, Nesaretnam K
    Br J Nutr, 2009 Mar;101(6):810-5.
    PMID: 18702848 DOI: 10.1017/S0007114508039998
    Vitamin E is divided into two subgroups; tocopherols and tocotrienols. Both have protective roles in biological systems. The present study was conducted to compare the effect of short-term supplementation at 200 mg/d of either alpha-tocopherol or a tocotrienol-rich fraction (TRF) from palm oil on immune modulation and plasma vitamin E levels in normal healthy Asian volunteers. In a randomised, double-blind placebo-controlled trial conducted, fifty-three healthy volunteers aged 20-50 years were recruited based on the study's inclusion and exclusion criteria. They were randomly assigned into three groups, i.e. two experimental groups that received daily supplementation at 200 mg of either alpha-tocopherol or the TRF, and the control group that received a placebo. Blood was drawn on days 0, 28 and 56 for several laboratory analyses. Differences in the production of IL-4 or interferon-gamma by concanavalin A-stimulated lymphocytes isolated from these volunteers were not significant (P>0.05). There were no significant differences observed in immune parameters between the healthy volunteers who received daily supplementation with either alpha-tocopherol or the TRF. As these observations were made in the absence of any immunogenic challenge, we feel it would be of benefit to study if there would be any differences observed when an immunogenic challenge such as vaccination were introduced.
    Matched MeSH terms: alpha-Tocopherol/administration & dosage*; alpha-Tocopherol/blood
  16. Is vitamin E toxic to neuron cells?
    Then SM, Mazlan M, Mat Top G, Wan Ngah WZ
    Cell Mol Neurobiol, 2009 Jun;29(4):485-96.
    PMID: 19172392 DOI: 10.1007/s10571-008-9340-8
    Besides acting as potent free radical scavengers, tocopherols and tocotrienols have been known to have non-antioxidant properties such as the involvement of alpha-tocopherol (alphaT) in PKC pathway and the anti-cancer properties of gamma-tocotrienol (gammaT3). This study aims to elucidate whether protective effects shown by alphaT and gammaT3 in H(2)O(2)-induced neuron cultures have anti-apoptotic or pro-apoptotic tendency toward the initiation of neuronal apoptosis. H(2)O(2) is used to induce apoptosis in primary cerebellar neuron cultures which is attenuated by pretreatment of alphaT or gammaT3 at concentrations < or =10 microM. Similar to our previous work, gammaT3 was found to be neurotoxic at concentrations > or =100 microM, whereas alphaT showed no neurotoxicity. Cellular uptake of gammaT3 was higher than that of alphaT. Treating cells simultaneously with either gammaT3 or alphaT and with then H(2)O(2) led to higher expression of Bax and Bcl-2 than in neurons exposed to H(2)O(2) alone. Analysis of Bcl-2/Bax ratio as 'survival index' showed that both pretreatment of gammaT3 and alphaT followed by H(2)O(2) increase the 'survival index' of Bcl-2/Bax ratio compared to H(2)O(2)-treated cells, while treatment of gammaT3 alone decrease the ratio compared to unchanged Bcl2/Bax ratio of similar treatment with alphaT alone. Similar treatment of gammaT3 decreased p53 expression and activates p38 MAPK phosphorylation, whereas alphaT did not alter its expression compared to H(2)O(2)-treated cells. Treating neurons with only gammaT3 or alphaT increased the expression of Bax, Bcl-2, p53, and p38 MAPK compared to control with gammaT3 exerting stronger expression for proteins involved than alphaT. In conclusion, low doses of gammaT3 and alphaT confer neuroprotection to H(2)O(2)-treated neurons via their antioxidant mechanism but gammaT3 has stronger pro-apoptosis tendency than alphaT by activating molecules involved in the neuronal apoptotic pathway in the absence of H(2)O(2).
    Matched MeSH terms: alpha-Tocopherol/pharmacology
  17. Effect of alpha-tocopherol supplementation on renal oxidative stress and Na+/K+ -adenosine triphosphatase in ethanol treated Wistar rats
    Mailankot M, Jayalekshmi H, Chakrabarti A, Alang N, Vasudevan DM
    Indian J Exp Biol, 2009 Jul;47(7):608-10.
    PMID: 19761047
    Ethanol intoxication resulted in high extent of lipid peroxidation, and reduction in antioxidant defenses (decreased GSH, GSH/GSSG ratio, and catalase, SOD and GPx activities) and (Na+/K+)-ATPase activity in kidney. Alpha-tocopherol treatment effectively protected kidney from ethanol induced oxidative challenge and improved renal (Na+/K+)-ATPase activity. Ethanol induced oxidative stress in the kidney and decreased (Na+/K+)-ATPase activity could be reversed by treatment with ascorbic acid.
    Matched MeSH terms: alpha-Tocopherol/administration & dosage*
  18. Tocotrienols suppress proinflammatory markers and cyclooxygenase-2 expression in RAW264.7 macrophages
    Yam ML, Abdul Hafid SR, Cheng HM, Nesaretnam K
    Lipids, 2009 Sep;44(9):787-97.
    PMID: 19655189 DOI: 10.1007/s11745-009-3326-2
    Tocotrienols are powerful chain breaking antioxidant. Moreover, they are now known to exhibit various non-antioxidant properties such as anti-cancer, neuroprotective and hypocholesterolemic functions. This study was undertaken to investigate the anti-inflammatory effects of tocotrienol-rich fraction (TRF) and individual tocotrienol isoforms namely delta-, gamma-, and alpha-tocotrienol on lipopolysaccharide-stimulated RAW264.7 macrophages. The widely studied vitamin E form, alpha-tocopherol, was used as comparison. Stimulation of RAW264.7 with lipopolysaccharide induced the release of various inflammatory markers. 10 mcirog/ml of TRF and all tocotrienol isoforms significantly inhibited the production of interleukin-6 and nitric oxide. However, only alpha-tocotrienol demonstrated a significant effect in lowering tumor necrosis factor-alpha production. Besides, TRF and all tocotrienol isoforms except gamma-tocotrienol reduced prostaglandin E(2) release. It was accompanied by the down-regulation of cyclooxygenase-2 gene expression by all vitamin E forms except alpha-tocopherol. Collectively, the data suggested that tocotrienols are better anti-inflammatory agents than alpha-tocopherol and the most effective form is delta-tocotrienol.
    Matched MeSH terms: alpha-Tocopherol/pharmacology
  19. Fulltext Cytotoxic components of Pereskia bleo (Kunth) DC. (Cactaceae) leaves
    Malek SN, Shin SK, Wahab NA, Yaacob H
    Molecules, 2009;14(5):1713-24.
    PMID: 19471192 DOI: 10.3390/molecules14051713
    Dihydroactinidiolide (1) and a mixture of sterols [campesterol (2), stigmasterol (3) and beta-sitosterol (4)], together with the previously isolated individual compounds beta-sitosterol (4), 2,4-di-tert-butylphenol (5), alpha-tocopherol (6), phytol (7) were isolated from the active ethyl acetate fraction of Pereskia bleo (Kunth) DC. (Cactaceae) leaves. Cytotoxic activities of the above mentioned compounds against five human carcinoma cell lines, namely the human nasopharyngeal epidermoid carcinoma cell line (KB), human cervical carcinoma cell line (CasKi), human colon carcinoma cell line (HCT 116), human hormone-dependent breast carcinoma cell line (MCF7) and human lung carcinoma cell line (A549); and non-cancer human fibroblast cell line (MRC-5) were investigated. Compound 5 possessed very remarkable cytotoxic activity against KB cells, with an IC(50 )value of 0.81microg/mL. This is the first report on the cytotoxic activities of the compounds isolated from Pereskia bleo.
    Matched MeSH terms: alpha-Tocopherol/pharmacology
  20. Fulltext Bioaccessibility of carotenoids and tocopherols in marine microalgae, Nannochloropsis sp. and Chaetoceros sp.
    Goh, L.P., Loh, S.P., Fatimah, M.Y., Perumal, K.
    Malays J Nutr, 2009;15(1):77-86.
    MyJurnal
    Microalgae can produce various natural products such as pigments, enzymes, unique fatty acids and vitamin that benefit humans. The objective of the study is to study the bioaccessibility of carotenoids (β-carotene and lycopene) and vitamin E (α- and β-tocopherol) of Nannochloropsis oculata and Chaetoceros calcitrans. Analyses were carried out for both the powdered forms of N. oculata and C. calcitrans, and the dried extract forms of N. oculata and C. calcitrans. In vitro digestion method together with RP-HPLC was used to determine the bioaccessibility of carotenoids and vitamin E for both forms of microalgae. Powdered form of N. oculata had the highest bioaccessibility of β-carotene (28.0 ± 0.6 g kg-1), followed by dried extract N. oculata (21.5 ± 1.1 g kg-1), dried extract C. calcitrans (16.9 ± 0.1 g kg-1), and powdered C. calcitrans (15.6 ± 0.1 g kg-1). For lycopene, dried extract of N. oculata had the highest bioaccessibility of lycopene (42.6 ± 1.1 g kg-1), followed by dried extract C. calcitrans (41.9 ± 0.6 g kg-1), powdered C. calcitrans (39.7 ± 0.1 g kg-1) and powdered N. oculata (32.6 ± 0.7 g kg-1). Dried extract C. calcitrans had the highest bioaccessibility of α-tocopherol (72.1 ± 1.2 g kg-1). However, β-tocopherol was not detected in both dried extract and powdered form of C. calcitrans. In conclusion, all samples in their dried extract forms were found to have significantly higher bioaccessibilities than their powdered forms. This may be due to the disruption of the food matrix contributing to a higher bioaccessibility of nutrients shown by the dried extract forms.
    Matched MeSH terms: alpha-Tocopherol
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