Displaying publications 821 - 840 of 1845 in total

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  1. Moghadamtousi SZ, Goh BH, Chan CK, Shabab T, Kadir HA
    Molecules, 2013 Aug 30;18(9):10465-83.
    PMID: 23999722 DOI: 10.3390/molecules180910465
    Swietenia macrophylla King (Meliaceae) is an endangered and medicinally important plant indigenous to tropical and subtropical regions of the World. S. macrophylla has been widely used in folk medicine to treat various diseases. The review reveals that limonoids and its derivatives are the major constituents of S. macrophylla. There are several data in the literature indicating a great variety of pharmacological activities of S. macrophylla, which exhibits antimicrobial, anti-inflammatory, antioxidant effects, antimutagenic, anticancer, antitumor and antidiabetic activities. Various other activities like anti-nociceptive, hypolipidemic, antidiarrhoeal, anti-infective, antiviral, antimalarial, acaricidal, antifeedant and heavy metal phytoremediation activity have also been reported. In view of the immense medicinal importance of S. macrophylla, this review aimed at compiling all currently available information on its ethnomedicinal uses, phytochemistry and biological activities of S. macrophylla, showing its importance.
    Matched MeSH terms: Antioxidants/pharmacology; Antioxidants/chemistry
  2. Azmi NH, Ismail N, Imam MU, Ismail M
    PMID: 23866310 DOI: 10.1186/1472-6882-13-177
    There are reports of improved metabolic outcomes due to consumption of germinated brown rice (GBR). Many of the functional effects of GBR can be linked to its high amounts of antioxidants. Interestingly, dietary components with high antioxidants have shown promise in the prevention of neurodegenerative diseases like Alzheimer's disease (AD). This effect of dietary components is mostly based on their ability to prevent apoptosis, which is believed to link oxidative damage to pathological changes in AD. In view of the rich antioxidant content of GBR, we studied its potential to modulate processes leading up to AD.
    Matched MeSH terms: Antioxidants/isolation & purification; Antioxidants/pharmacology*
  3. Kumar CS, Loh WS, Ooi CW, Quah CK, Fun HK
    Molecules, 2013 Oct 15;18(10):12707-24.
    PMID: 24132195 DOI: 10.3390/molecules181012707
    Chalcone derivatives have attracted increasing attention due to their numerous pharmacological activities. Changes in their structures have displayed high degree of diversity that has proven to result in a broad spectrum of biological activities. The present study highlights the synthesis of some halogen substituted chalcones 3(a-i) containing the 5-chlorothiophene moiety, their X-ray crystal structures and the evaluation of possible biological activities such as antibacterial, antifungal and reducing power abilities. The results indicate the tested compounds show a varied range of inhibition values against all the tested microbial strains. Compound 3c with a p-fluoro substituent on the phenyl ring exhibits elevated antimicrobial activity, whereas the compounds 3e and 3f displayed the least antimicrobial activities. The compounds 3d, 3e, 3f and 3i showed good ferric and cupric reducing abilities, and the compounds 3b and 3c showed the weakest reducing power in the series.
    Matched MeSH terms: Antioxidants/chemical synthesis; Antioxidants/pharmacology
  4. Mohd Esa N, Abdul Kadir KK, Amom Z, Azlan A
    Food Chem, 2013 Nov 15;141(2):1306-12.
    PMID: 23790918 DOI: 10.1016/j.foodchem.2013.03.086
    Antioxidant activity of different rice extract and the effect on the levels of antioxidant enzyme activity, superoxide dismutase (SOD) and glutathione peroxidase (GPx), vitamin E, lipid peroxidation and liver enzymes in hyperlipidaemia rabbits were investigated. Germinated brown rice (GBR) has the highest antioxidant activity compared to white rice (WR) and brown rice (BR). All rice grains increased the activity of SOD and GPx. However, vitamin E levels increased only in the groups that received the BR and GBR diets. The reduction of lipid peroxidation levels and activity of hepatic enzymes (alanine transferase, ALT and aspartate transaminase, AST) were only significantly observed in the GBR group. In conclusion, GBR supplementation has the greatest impact on increasing antioxidant enzyme activity and vitamin E level and on reducing lipid peroxidation in hypercholesterolaemia rabbit, thereby preventing the formation of atherosclerotic plaques. Furthermore, GBR diet can also reduce the level of hepatic enzymes.
    Matched MeSH terms: Antioxidants/metabolism*; Antioxidants/chemistry
  5. Alnajar ZA, Abdulla MA, Ali HM, Alshawsh MA, Hadi AH
    Molecules, 2012;17(3):3547-59.
    PMID: 22433579 DOI: 10.3390/molecules17033547
    Melastoma malabathricum (MM) is a well-known plant in Malaysian traditional medicine, locally known as senduduk. Its ethanol and aqueous extracts have been used in the present investigation to study the immunomodulatory role on human peripheral blood mononuclear cell (PBMC), and the DPPH, ABTS and FRAP free radical scavenging activities were also measured. Total flavonoids and total phenolic contents were assayed and the antibacterial effect was tested against four species of bacteria; two Gram-positive (Staphylococcus aureus and Streptococcus agalactiae) and two Gram-negative (Escherichia coli and Klebsilla pneumonia). The tests were carried out using the disc diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods. Moreover, the acute toxicity was evaluated in vivo on the ethanol extract of MM to establish its safety when administered orally. In our results, both extracts of MM showed abilities to scavenge DPPH and ABTS free radicals, IC(50) values: (11.599 ± 0.84, 10.573 ± 0.58 µmol/L) and (62.657 ± 0.78, 63.939 ± 0.48 µmol/L) for ethanol and aqueous extracts respectively. Indeed the ethanol extract evidenced high phenolic content (384.33 ± 0.005 mg/g), flavonoids contents (85.8 ± 0.009 mg/g) and ferric reducing antioxidant power (33,590 ± 0.038 mmol/g), with high activity against S. aureus and S. agalactiae (11 ± 0.3 and 12 ± 0.6 mm inhibition zones). Likewise, the percentage of peripheral blood mononuclear cells (PBMC) viability was increased in response to MM, IC(50) values (1.781 ± 1.2 and 6.545 ± 0.93 µg/mL) for ethanol and aqueous extracts, respectively. In addition, our results showed that the MM extract is safe even at a high dose of 5,000 mg/kg and has no oral toxicity. These findings suggest the excellent medicinal bioactivity of MM and explain the popularity of this plant in the folk medicine as a remedy for different illnesses.
    Matched MeSH terms: Antioxidants/pharmacology*; Antioxidants/chemistry*
  6. Sulaiman SF, Moon JK, Shibamoto T
    J Diet Suppl, 2011 Sep;8(3):293-310.
    PMID: 22432728 DOI: 10.3109/19390211.2011.593618
    In order to investigate the role of roasting conditions in antioxidant formation, methanol and hot water extracts from Robusta coffee beans roasted for various lengths of time and at various temperatures were analyzed for total phenolic acid, chlorogenic acid, and caffeine content, as well as for their antioxidant activities using 1,1-diphenyl-2-picryhydrazyl (DPPH), thiobarbituric acid (TBA), and malonaldehyde/gas chromatography (MA/GC) assays. The amount of total phenolics in methanol extracts decreased linearly over the roasting temperature from 63.51 ± 0.77 mg chlorogenic acid equivalent (CAE)/g coffee beans (roasted at 200°C) to 42.56 ± 0.33 mg CAE/g coffee beans (roasted at 240°C). The total chlorogenic acid content decreased when the roasting time was increased from 78.33 ± 1.41 mg/g (green coffee beans) to 4.31 ± 0.23 mg/g (roasted for 16 min at 250°C). All methanol extracts from roasted coffee beans possessed over 90% antioxidant activities in the DPPH assay. The antioxidant activity of methanol extracts ranged from 41.38 ± 1.77% (roasted at 250°C for 10 min) to 98.20 ± 1.49% (roasted at 230°C for 16 min) as tested by the TBA assay. The antioxidant activity of methanol extracts of green coffee beans and roasted coffee beans ranged from 93.01% (green coffee beans) to 98.62 ± 1.32% (roasted at 250°C for 14 min) in the MA/GC assays. All hot water extracts exhibited moderate pro-oxidant activities in TBA and MA/GC assays. The results indicated that roasting conditions of coffee beans play an important role in the formation of antioxidants in brewed coffee, which can be dietary supplements having beneficial effect to human health.
    Matched MeSH terms: Antioxidants/analysis; Antioxidants/pharmacology*
  7. Abdul Hamid Z, Budin SB, Wen Jie N, Hamid A, Husain K, Mohamed J
    J Zhejiang Univ Sci B, 2012 Mar;13(3):176-85.
    PMID: 22374609 DOI: 10.1631/jzus.B1100133
    Paracetamol (PCM) overdose can cause nephrotoxicity with oxidative stress as one of the possible mechanisms mediating the event. In this study, the effects of ethyl acetate extract of Zingiber zerumbet rhizome [200 mg per kg of body weight (mg/kg) and 400 mg/kg] on PCM-induced nephrotoxicity were examined. Rats were divided into five groups containing 10 rats each. The control group received distilled water while other groups were treated with extract alone (400 mg/kg), PCM alone (750 mg/kg), 750 mg/kg PCM+200 mg/kg extract (PCM+200-extract), and 750 mg/kg PCM+400 mg/kg extract (PCM+400-extract), respectively, for seven consecutive days. The Z. zerumbet extract was given intraperitoneally concurrent with oral administration of PCM. Treatment with Z. zerumbet extract at doses of 200 and 400 mg/kg prevented the PCM-induced nephrotoxicity and oxidative impairments of the kidney, as evidenced by a significantly reduced (P<0.05) level of plasma creatinine, plasma and renal malondialdehyde (MDA), plasma protein carbonyl, and renal advanced oxidation protein product (AOPP). Furthermore, both doses were also able to induce a significant increment (P<0.05) of plasma and renal levels of glutathione (GSH) and plasma superoxide dismutase (SOD) activity. The nephroprotective effects of Z. zerumbet extract were confirmed by a reduced intensity of renal cellular damage, as evidenced by histological findings. Moreover, Z. zerumbet extract administered at 400 mg/kg was found to show greater protective effects than that at 200 mg/kg. In conclusion, ethyl acetate extract of Z. zerumbet rhizome has a protective role against PCM-induced nephrotoxicity and the process is probably mediated through its antioxidant properties.
    Matched MeSH terms: Antioxidants/administration & dosage; Antioxidants/pharmacology
  8. Ibrahim MH, Jaafar HZ, Rahmat A, Rahman ZA
    Int J Mol Sci, 2012;13(1):393-408.
    PMID: 22312260 DOI: 10.3390/ijms13010393
    A split plot 3 by 4 experiment was designed to characterize the relationship between production of gluthatione (GSH), oxidized gluthatione (GSSG), total flavonoid, anthocyanin, ascorbic acid and antioxidant activities (FRAP and DPPH) in three varieties of Labisia pumila Blume, namely the varieties alata, pumila and lanceolata, under four levels of nitrogen fertilization (0, 90, 180 and 270 kg N/ha) for 15 weeks. The treatment effects were solely contributed by nitrogen application; there was neither varietal nor interaction effects observed. As the nitrogen levels decreased from 270 to 0 kg N/ha, the production of GSH and GSSG, anthocyanin, total flavonoid and ascorbic acid increased steadily. At the highest nitrogen treatment level, L. pumila exhibited significantly lower antioxidant activities (DPPH and FRAP) than those exposed to limited nitrogen growing conditions. Significant positive correlation was obtained between antioxidant activities (DPPH and FRAP), total flavonoid, GSH, GSSG, anthocyanin and ascorbic acid suggesting that an increase in the antioxidative activities in L. pumila under low nitrogen fertilization could be attributed to higher contents of these compounds. From this observation, it could be concluded that in order to avoid negative effects on the quality of L. pumila, it is advisable to avoid excessive application of nitrogen fertilizer when cultivating the herb for its medicinal use.
    Matched MeSH terms: Antioxidants/metabolism; Antioxidants/chemistry*
  9. Mohamed S, Lee Ming T, Jaffri JM
    J Sci Food Agric, 2013 Mar 15;93(4):819-27.
    PMID: 23001939 DOI: 10.1002/jsfa.5802
    Catechin-rich oil palm (Elaeis guineensis) leaf extract (OPLE) has good cardiovascular and phytoestrogenic properties. The OPLE (0.5 g day(-1) ) was supplemented to young, healthy, adult human volunteers, and their cognitive learning abilities were compared to placebo-controlled groups (N = 15). Their short-term memories, spatial visualisations, processing speeds, and language skills, were assessed over 2 months by cognitive tests computer programs.
    Matched MeSH terms: Antioxidants/metabolism; Antioxidants/pharmacology*
  10. Isa NM, Abdelwahab SI, Mohan S, Abdul AB, Sukari MA, Taha MM, et al.
    Braz. J. Med. Biol. Res., 2012 Jun;45(6):524-30.
    PMID: 22358425
    The current in vitro study was designed to investigate the anti-inflammatory, cytotoxic and antioxidant activities of boesenbergin A (BA), a chalcone derivative of known structure isolated from Boesenbergia rotunda. Human hepatocellular carcinoma (HepG2), colon adenocarcinoma (HT-29), non-small cell lung cancer (A549), prostate adenocarcinoma (PC3), and normal hepatic cells (WRL-68) were used to evaluate the cytotoxicity of BA using the MTT assay. The antioxidant activity of BA was assessed by the ORAC assay and compared to quercetin as a standard reference antioxidant. ORAC results are reported as the equivalent concentration of Trolox that produces the same level of antioxidant activity as the sample tested at 20 µg/mL. The toxic effect of BA on different cell types, reported as IC50, yielded 20.22 ± 3.15, 10.69 ± 2.64, 20.31 ± 1.34, 94.10 ± 1.19, and 9.324 ± 0.24 µg/mL for A549, PC3, HepG2, HT-29, and WRL-68, respectively. BA displayed considerable antioxidant activity, when the results of ORAC assay were reported as Trolox equivalents. BA (20 µg/mL) and quercetin (5 µg/mL) were equivalent to a Trolox concentration of 11.91 ± 0.23 and 160.32 ± 2.75 µM, respectively. Moreover, the anti-inflammatory activity of BA was significant at 12.5 to 50 µM and without any significant cytotoxicity for the murine macrophage cell line RAW 264.7 at 50 µM. The significant biological activities observed in this study indicated that BA may be one of the agents responsible for the reported biological activities of B. rotunda crude extract.
    Matched MeSH terms: Antioxidants/pharmacology*; Antioxidants/therapeutic use
  11. Hendra R, Ahmad S, Oskoueian E, Sukari A, Shukor MY
    PMID: 22070850 DOI: 10.1186/1472-6882-11-110
    Phaleria macrocarpa (Scheff.) Boerl (Thymelaceae) originates from Papua Island, Indonesia and grows in tropical areas. The different parts of the fruit of P. macrocarpa were evaluated for antioxidant, anti-inflammatory, and cytotoxic activities.
    Matched MeSH terms: Antioxidants/analysis; Antioxidants/pharmacology*
  12. Akinboro A, Mohamed KB, Asmawi MZ, Sulaiman SF, Sofiman OA
    J Zhejiang Univ Sci B, 2011 Nov;12(11):915-22.
    PMID: 22042656 DOI: 10.1631/jzus.B1000315
    In this study, freeze-dried water extract from the leaves of Myristica fragrans (Houtt.) was tested for mutagenic and antimutagenic potentials using the Allium cepa assay. Freeze-dried water extract alone and its combination with cyclophosphamide (CP) (50 mg/kg) were separately dissolved in tap water at 500, 1000, 2000, and 4000 mg/kg. Onions (A. cepa) were suspended in the solutions and controls for 48 h in the dark. Root tips were prepared for microscopic evaluation. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) free radicals' scavenging power of the extract was tested using butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) as standards. Water extract of Myristica fragrans scavenged free radicals better than BHA, but worse than BHT. The extract alone, as well as in combination with CP suppressed cell division, and induced chromosomal aberrations that were insignificantly different from the negative control (P ≤ 0.05). However, cytotoxic and mutagenic actions of CP were considerably suppressed. The observed effects on cell division and chromosomes of A. cepa may be principally connected to the antioxidant properties of the extract. The obtained results suggest mitodepressive and antimutagenic potentials of water extract of the leaves of M. fragrans as desirable properties of a promising anticancer agent.
    Matched MeSH terms: Antioxidants/isolation & purification; Antioxidants/pharmacology*
  13. Nathan FM, Singh VA, Dhanoa A, Palanisamy UD
    BMC Cancer, 2011;11:382.
    PMID: 21871117 DOI: 10.1186/1471-2407-11-382
    Oxidative stress is characterised by an increased level of reactive oxygen species (ROS) that disrupts the intracellular reduction-oxidation (redox) balance and has been implicated in various diseases including cancer. Malignant tumors of connective tissue or sarcomas account for approximately 1% of all cancer diagnoses in adults and around 15% of paediatric malignancies per annum. There exists no information on the alterations of oxidant/antioxidant status of sarcoma patients in literature. This study was aimed to determine the levels of oxidative stress and antioxidant defence in patients with primary bone and soft tissue sarcoma and to investigate if there exists any significant differences in these levels between both the sarcomas.
    Matched MeSH terms: Antioxidants/analysis; Antioxidants/metabolism*
  14. Sambanthamurthi R, Tan Y, Sundram K, Abeywardena M, Sambandan TG, Rha C, et al.
    Br J Nutr, 2011 Dec;106(11):1655-63.
    PMID: 21736792 DOI: 10.1017/S0007114511002121
    Waste from agricultural products represents a disposal liability, which needs to be addressed. Palm oil is the most widely traded edible oil globally, and its production generates 85 million tons of aqueous by-products annually. This aqueous stream is rich in phenolic antioxidants, which were investigated for their composition and potential in vitro biological activity. We have identified three isomers of caffeoylshikimic acid as major components of oil palm phenolics (OPP). The 2,2-diphenyl-1-picrylhydrazyl assay confirmed potent free radical scavenging activity. To test for possible cardioprotective effects of OPP, we carried out in vitro LDL oxidation studies as well as ex vivo aortic ring and mesenteric vascular bed relaxation measurements. We found that OPP inhibited the Cu-mediated oxidation of human LDL. OPP also promoted vascular relaxation in both isolated aortic rings and perfused mesenteric vascular beds pre-contracted with noradrenaline. To rule out developmental toxicity, we performed teratological studies on rats up to the third generation and did not find any congenital anomalies. Thus, these initial studies suggest that OPP is safe and may have a protective role against free radical damage, LDL oxidation and its attendant negative effects, as well as vascular constriction in mitigating atherosclerosis. Oil palm vegetation liquor thus represents a new source of phenolic bioactives.
    Matched MeSH terms: Antioxidants/analysis; Antioxidants/pharmacology
  15. Aizzat O, Yap SW, Sopiah H, Madiha MM, Hazreen M, Shailah A, et al.
    Adv Med Sci, 2010;55(2):281-8.
    PMID: 21147697 DOI: 10.2478/v10039-010-0046-z
    Chlorella vulgaris (CV), a fresh water alga has been reported to have hypoglycemic effects. However, antioxidant and anti-inflammatory effects of CV in diabetic animals have not been investigated to date. The aim of the present study was to investigate the role of CV in inflammation and oxidative damage in STZ-induced diabetic rats.
    Matched MeSH terms: Antioxidants/therapeutic use*; Antioxidants/chemistry
  16. Hashim P, Sidek H, Helan MH, Sabery A, Palanisamy UD, Ilham M
    Molecules, 2011;16(2):1310-22.
    PMID: 21278681 DOI: 10.3390/molecules16021310
    Leaves of Centella asiatica (Centella) were analysed for their triterpene composition and bioactivity such as collagen enhancement, antioxidant, anticellulite and UV protection capacity properties. Triterpenes of Centella were measured using HPLC-PAD on an Excil ODS 5 mm (C18) column for the simultaneous determination of asiatic acid, madecassic acid, asiaticoside and madecassoside. Centella was found to contain significant amounts of madecassoside (3.10 ± 4.58 mg/mL) and asiaticoside (1.97 ± 2.65 mg/mL), but was low in asiatic and madecassic acid. The highest collagen synthesis was found at 50 mg/mL of Centella extracts. The antioxidant activity of Centella (84%) was compared to grape seed extract (83%) and Vitamin C (88%). Its lipolytic activity was observed by the release of glycerol (115.9 µmol/L) at 0.02% concentration. Centella extracts exhibited similar UV protection effect to OMC at 10% concentration. In view of these results, the potential application of Centella in food and pharmaceutical industries is now widely open.
    Matched MeSH terms: Antioxidants/metabolism; Antioxidants/chemistry
  17. Yam MF, Ang LF, Salman IM, Ameer OZ, Lim V, Ong LM, et al.
    J Med Food, 2009 Oct;12(5):1089-97.
    PMID: 19857074 DOI: 10.1089/jmf.2008.0005
    Orthosiphon stamineus Benth., which is used as a gastroprotective herbal remedy in Malaysia, was assessed for its anti-ulcerogenic activity against ethanol-induced ulcers in rats. Fifty percent methanol was used to extract the oven-dried O. stamineus leaves. The extract was then lyophilized with a rotary evaporator and freeze-dried. Oral administration of O. stamineus methanolic extract (OSME) (125, 250, 500, and 1,000 mg/kg) was found to significantly decrease the ulcer index (P < .01, P < .001, P < .001, and P < .001, respectively). Histological study of a section of the rat stomach also showed a marked improvement in the gastric mucosal damage in groups receiving OSME. In order to further investigate the gastroprotective mechanism of OSME, mucus secretion and lipid peroxidation level were estimated in vitro and ex vivo. OSME exhibited dose-dependent stimulation of mucus secretion (r = 0.718, P < .001) and inhibition of lipid peroxidation in rat gastric mucosal homogenates (both in vitro [r = 0.819, P < .05] and ex vivo [r = 0.981, P < .05]). It was concluded that the gastroprotective mechanism of OSME was partly due to its ability to inhibit lipid peroxidation and stimulate gastric mucus secretion.
    Matched MeSH terms: Antioxidants/pharmacology; Antioxidants/therapeutic use*
  18. Nor FM, Suhaila M, Aini IN, Razali I
    Int J Food Sci Nutr, 2009;60 Suppl 2:1-11.
    PMID: 19488917 DOI: 10.1080/09637480802158168
    Murraya koenigii leaf extract antioxidant potentials were evaluated in palm olein using accelerated oxidation storage and deep-frying studies at 180 degrees C for up to 40 h. The extracts (0.2%) retarded oil oxidation and deterioration significantly (P<0.05), slightly less effectively than 0.02% butylated hydroxytoluene in tests such as the peroxide value, anisidine value, iodine value, free fatty acid, Oxidative Stability Index, and polar and polymer compound content. Sensory evaluation on French fries indicated that the extract was useful in improving colour, flavour and overall acceptability and the quality of the fried product. All samples were more acceptable by panellists, especially after the 40th hour frying, compared with those similarly fried in the control oils and the oil containing butylated hydroxytoluene. M. koenigii leaf extract, had a polyphenol content of 109.5+/-0.3 mg gallic acid equivalents/g extract, and contain a heat-stable antioxidant that could be a natural alternative to synthetic antioxidants for the industry.
    Matched MeSH terms: Antioxidants/isolation & purification; Antioxidants/pharmacology*
  19. Indran M, Mahmood AA, Kuppusamy UR
    West Indian Med J, 2008 Sep;57(4):323-6.
    PMID: 19566009
    The effects of Carica papaya leaf (CPL) aqueous extract on alcohol induced acute gastric damage and the immediate blood oxidative stress level were studied in rats. The results showed that gastric ulcer index was significantly reduced in rats pretreated with CPL extract as compared with alcohol treated controls. The in vitro studies using 2,2-Diphenyl-1-Picryl-Hydrazyl (DPPH) assay showed strong antioxidant nature of CPL extract. Biochemical analysis indicated that the acute alcohol induced damage is reflected in the alterations of blood oxidative indices and CPL extract offered some protection with reduction in plasma lipid peroxidation level and increased erythrocyte glutathione peroxidase activity. Carica papaya leaf may potentially serve as a good therapeutic agent for protection against gastric ulcer and oxidative stress.
    Matched MeSH terms: Antioxidants/pharmacology; Antioxidants/therapeutic use
  20. 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: Antioxidants/metabolism; Antioxidants/pharmacology
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