Displaying publications 1 - 20 of 1831 in total

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  1. Ngah WZ, Jarien Z, San MM, Marzuki A, Top GM, Shamaan NA, et al.
    Am J Clin Nutr, 1991 04;53(4 Suppl):1076S-1081S.
    PMID: 1672785 DOI: 10.1093/ajcn/53.4.1076S
    The effects of tocotrienols on hepatocarcinogenesis in rats fed with 2-acetylaminofluorene (AAF) were followed morphologically and histologically for a period of 20 wk. No differences between treated and control rats in the morphology and histology of their livers was observed. Cell damage was extensive in the livers of AAF-treated rats but less extensive in the AAF-tocotrienols-treated rats when compared with normal and tocotrienols-treated rats. 2-Acetylaminofluorene significantly increases the activities of both plasma and liver microsomal gamma-glutamyltranspeptidase (GGT) and liver microsomal UDP-glucuronyltransferase (UDP-GT). Tocotrienols administered together with AAF significantly decrease the activities of plasma GGT after 12 and 20 wk (P less than 0.01, P less than 0.002, respectively) and liver microsomal UDP-GT after 20 wk (P less than 0.02) when compared with the controls and with rats treated only with tocotrienols. Liver microsomal GGT also showed a similar pattern to liver microsomal UDP-GT but the decrease was not significant. These results suggest that tocotrienols administered to AAF-treated rats reduce the severity of hepatocarcinogenesis.
    Matched MeSH terms: Antioxidants/therapeutic use*
  2. Zaiton Z, Merican Z, Khalid BA, Mohamed JB, Baharom S
    Gen. Pharmacol., 1993 Jan;24(1):195-9.
    PMID: 8482496
    1. The mean levels of lipid peroxidation products, namely conjugated diene and malonaldehyde, were increased in the soleus muscles of hyperthyroid cats, while the mean glutathione peroxidase activity was decreased. No corresponding similar changes were noted in the fast extensor digitorum longus muscles and serum. 2. Propranolol administration prevented the increase in conjugated diene level in the soleus muscles of hyperthyroid cat but not the malonaldehyde level. It also prevented the reduction in glutathione peroxidase activity in the slow oxidative soleus muscles of hyperthyroid cats. 3. Maximal twitch tension, subtetanic tension and maximum tetanic tension of soleus and EDL muscles were reduced in hyperthyroid cats. Propranolol administration for 5 weeks to hyperthyroid cats did not prevent the reduction in tension of contractions of these muscles. 4. It is suggested that lipid peroxidation might not be responsible for the myopathy in hyperthyroidism and propranolol administration does not improve skeletal muscle function in hyperthyroid animals.
    Matched MeSH terms: Antioxidants/metabolism*
  3. Lim VK
    Med J Malaysia, 1993 Dec;48(4):379-80.
    PMID: 8183159
    Matched MeSH terms: Antioxidants/therapeutic use
  4. Teoh MK, Chong JMK, Mohamed J, Phang KS
    Med J Malaysia, 1994 Sep;49(3):255-62.
    PMID: 7845276
    Antioxidants such as tocotrienols may protect against atherosclerosis since tissue injury from free radicals is a final common pathway of damage in arterial disease. In this study, the effects of tocotrienols on serum cholesterol, lipid peroxides, and aorta atheroma were assessed in rabbits fed an atherogenic diet for 12 weeks. Tocotrienols were more effective than tocopherols in preventing increases in serum LDL (p = 0.03) and total cholesterol (p = 0.008) levels in the cholesterol-fed rabbits. Elevation of serum lipid peroxides was effectively suppressed by tocotrienols (p = 0.01). Both tocopherols and tocotrienols offered significant protection against atheroma in the rabbit aorta, but tocotrienols had a stronger hypolipidaemic effect.
    Comment in: Pathmanathan R, Wong KT. Protection by tocotrienols against hypercholesterolaemia and atheroma. Med J Malaysia. 1995 Mar;50(1):117
    Matched MeSH terms: Antioxidants/therapeutic use*
  5. Nesaretnam K, Guthrie N, Chambers AF, Carroll KK
    Lipids, 1995 Dec;30(12):1139-43.
    PMID: 8614304
    The tocotrienol-rich fraction (TRF) of palm oil consists of tocotrienols and some alpha-tocopherol (alpha-T). Tocotrienols are a form of vitamin E having an unsaturated side-chain, rather than the saturated side-chain of the more common tocopherols. Because palm oil has been shown not to promote chemically-induced mammary carcinogenesis, we tested effects of TRF and alpha-T on the proliferation, growth, and plating efficiency (PE) of the MDA-MB-435 estrogen-receptor-negative human breast cancer cells. TRF inhibited the proliferation of these cells with a concentration required to inhibit cell proliferation by 50% of 180 microgram/mL whereas alpha-T had no effect at concentrations up to 1000 microgram/mL as measured by incorporation of [3H]thymidine. The effects of TRF and alpha-T also were tested in longer-term growth experiments, using concentrations of 180 and 500 microgram/mL. We found that TRF inhibited the growth of these cells by 50%, whereas alpha-T did not. Their effect on the ability of these cells to form colonies also was studied, and it was found that TRF inhibited PE, whereas alpha T had no effect. These results suggest that the inhibition is due to the presence of tocotrienols in TRF rather than alpha T.
    Matched MeSH terms: Antioxidants/pharmacology
  6. Ima-Nirwana S, Merican Z, Jamaluddin M, Viswanathan P, Khalid BA
    Asia Pac J Clin Nutr, 1996 Jun;5(2):100-4.
    PMID: 24394519
    The atherogenic potential of soybean oil (Sb) and palm oil (PO) was compared by measuring lipid profile, lipid peroxidation (LP) and activity of the antioxidant enzyme glutathione peroxidase (GSHPx) in rat sera and liver and heart homogenates. Male Rattus norwegicus rats were fed a basal diet, or basal diet fortified with 20% weight/ weight Sb or PO for 4 or 9 months. There was no difference in high density lipoprotein cholesterol:low density lipoprotein cholesterol ratio between the two groups, but triglyceride concentrations were higher in the PO fed rats compared to the Sb fed rats, although the difference diminished after 9 months. No differences in serum LP and GSHPx activity were seen between the two groups. In the liver and heart, LP was lower in PO after 4 months feeding, but the reverse was seen after 9 months. Liver and heart GSHPx activity was higher in the PO group after both treatment periods. In conclusion, both PO and Sb fed rats appeared comparable in their lipid profile, but the PO food had a temporary beneficial effect on the LP process in liver and heart. GSHPx activity however did not correlate well with LP in liver and heart, suggesting involvement of other antioxidants.
    Matched MeSH terms: Antioxidants
  7. Adam A, Marzuki A, Ngah WZ, Top GM
    Pharmacol. Toxicol., 1996 Dec;79(6):334-9.
    PMID: 9000262
    The hepatic and pulmonary effects of nitrofurantoin (40 mg/kg, intraperitoneally) were determined at 4 and 24 hr following its administration in mice fed for 10 weeks with a vitamin E sufficient, deficient or enriched diet. Liver glutathione (GSH) was reduced by nitrofurantoin at 4 hr but was unchanged 20 hr later. Nitrofurantoin did not affect liver glutathione peroxidase, glutathione reductase or superoxide dismutase activities. Liver catalase activities were decreased by nitrofurantoin at 4 hr. Lung GSH levels were increased whilst glutathione peroxidase activity was decreased at 4 and 24 hr. Lung glutathione reductase activity was reduced in certain groups. Nitrofurantoin did not affect lung superoxide dismutase, but catalase was decreased at 24 hr. Liver malondialdehyde levels were increased by nitrofurantoin in the vitamin E deficient group whilst lung malondialdehyde levels remained unchanged. Both liver and lung malondialdehyde levels were unaffected by vitamin E supplementation when compared to the vitamin E-sufficient group. These results suggest that nitrofurantoin (40 mg/kg) was deleterious to the liver and lung. Nitrofurantoin-induced lipid peroxidation was seen in vitamin E deficiency but an increase in dietary vitamin E content did not provide additional protection compared to the recommended daily allowance. The antioxidant activities of alpha-tocopherol and gamma-enriched tocotrienol were similar.
    Matched MeSH terms: Antioxidants/pharmacology*
  8. Khor GL
    Asia Pac J Clin Nutr, 1997 Jun;6(2):122-42.
    PMID: 24394715
    Changes in the dietary intake patterns of countries in the Asia Pacific region are considered in relation to trends of cardiovascular disease mortality. Cardiovascular disease now constitutes the major cause of mortality in many of the countries of the region. The mortality rate for coronary heart disease (CHD) has been on the decline since the mid-1960s in countries such as Australia, New Zealand and Japan, while a decline in other countries, including Singapore and Hong Kong, appears to be occurring about two decades later after a delayed increase. In contrast, countries like Malaysia and China have had and continue an upward trend for CHD mortality. Nonetheless, the mortality rates due to CHD in New Zealand, Australia, Singapore followed by Hong Kong rank among the highest in the region. In China, Taiwan and Japan, death due to cerebrovascular disease remains a major cause of death, although the latter two countries have undergone a significant decline in stroke death rates since 1970. The intakes of fat from land animal products, fish and vegetable oils, depending on fatty acid patterns and, possibly other constituents, are candidate contributors to the different atherogenic and thrombotic effects. Countries which have a higher mortality from CHD tend to have a higher intake of energy from fat and proportion of fat from animal products. These fat intakes may operate to increase hypercholesterolemia and overweight in various countries. Again, intakes of other food items and constituents used in the region such as soybeans, dietary antioxidants in fruits, vegetables, seeds, cereals, nuts and tea and alcohol consumption are candidate cardio-protectants. The wide dietary scope of Asia Pacific populations, from diverse socio-cultural backgrounds, and at different levels of economic and technological development poses several analytic challenges and opportunities. Future research should improve the datasets and think laterally about pathogenesis and intervention.
    Matched MeSH terms: Antioxidants
  9. Newaz MA, Nawal NN
    Am J Hypertens, 1998 Dec;11(12):1480-5.
    PMID: 9880131
    The aim of this study was to determine the effects of alpha-tocopherol on lipid peroxidation and total antioxidant status of spontaneously hypertensive rats (SHR), comparing them with normal Wistar-Kyoto (WKY) rats. SHR were divided into three groups and treated with different doses of alpha-tocopherol (alpha1, 17 mg/kg diet; alpha2, 34 mg/kg diet; and alpha3, 170 mg/kg diet). Normal WKY and untreated SHR were used as normal (N) and hypertensive control (HC). Blood pressures were recorded every 10 days for 3 months. At the end of the trial, animals were killed and measurement of plasma total antioxidant status, plasma superoxide dismutase (SOD) activity, and lipid peroxide levels in plasma and blood vessels was carried out following well-established methods. From our study it was found that lipid peroxides in thoracic aorta (N, 0.47 +/- 0.17; H, 0.96 +/- 0.37; P < .0001) and plasma (N, 0.06 +/- 0.01; H, 0.13 +/- 0.01) were significantly higher in hypertensives than in normal rats. SOD activity was significantly lower in hypertensive than normal rats (N, 172.93 +/- 46.91; H, 110.08 +/- 14.38; P < .005). Total antioxidant status was significantly higher in normal than hypertensive rats (N, 0.88 +/- 0.05; H, 0.83 +/- 0.02; P < .05). After the antioxidant trial, it was found that in the treated groups rise of blood pressure was prevented significantly (P < .001) and lipid peroxides in blood vessels were significantly reduced more than in the controls (P < .001). For plasma lipid peroxide it was only significant for groups alpha2 (P < .001) and alpha3 (P < .05). Although all three treated groups showed improved total antioxidant status, only groups alpha2 (0.87 +/- 0.04, P < .005) and alpha3 (1.20 +/- 0.18, P < .001) were statistically significant. All the three groups showed significant increases in their SOD activity (P < .001). Correlation studies showed that total antioxidant status and SOD were significantly negatively correlated with blood pressure in normal rats (P = .007; P = .008). Lipid peroxides in both blood vessel and plasma showed a positive correlation. In the treated groups, lipid peroxides in blood vessels maintained a significant positive correlation with blood pressure in all groups (alpha1, P = .021; alpha2, P = .019; alpha3, P = .002), whereas for plasma lipid peroxides the correlation was in groups alpha1 (P = .005) and alpha2 (P = .009). For SOD activity, significant negative correlations were found with blood pressure in the alpha2 (P = .017) and alpha3 (P = .025) groups. Total antioxidant status maintained a significant negative correlation with blood pressure in all three groups (alpha1, P = .012; alpha2, P = .044; alpha3, P = .014). In conclusion it was found that supplement of alpha-tocopherol may prevent development of increased blood pressure, reduce lipid peroxides in plasma and blood vessels, and enhance the total antioxidant status, including SOD activity.
    Matched MeSH terms: Antioxidants/pharmacology*
  10. Marcus SR, Chandrakala MV, Nadiger HA
    Asia Pac J Clin Nutr, 1998 Dec;7(3/4):201-5.
    PMID: 24393672
    The protection against ethanol-induced lipid peroxidation is rendered by antioxidants such as vitamin E and glutathione (GSH) interacting with each other and also functioning independently. A study of the levels of GSH and activities of glutathione peroxidase (GP), glutathione reductase (GR) and glutathione transferase (GST) in the cerebral cortex (CC), cerebellum (CB) and brain stem (BS) of vitamin E-supplemented and -deficient rats subjected to ethanol administration for 30 days was carried out. Chronic ethanol administration to vitamin E-supplemented rats elevated GP, GR and GST activities in the three regions and GSH levels in the CB. Chronic ethanol administration to vitamin E-deficient rats elevated GR activity in the three regions and GP activity in the CC and CB, decreased GST activity in the CC and CB, but did not alter GSH levels compared with normal rats subjected to chronic ethanol administration. The results indicate that vitamin E helps to maintain GSH levels to combat increased peroxidation while its absence has a deleterious effect.
    Matched MeSH terms: Antioxidants
  11. Newaz MA, Nawal NN
    Clin Exp Hypertens, 1999 Nov;21(8):1297-313.
    PMID: 10574414
    The aim of this study was to determine the effects of gamma tocotrienol on lipid peroxidation and total antioxidant status of spontaneously hypertensive rats (SHR), comparing them with normal Wistar Kyoto (WKY) rats. SHR were divided into three groups and treated with different doses of gamma tocotrienol (gamma1, 15 mg/kg diet; gamma2, 30 mg/kg diet and gamma3, 150 mg/kg diet). Normal WKY and untreated SHR were used as normal (N) and hypertensive control (HC). Blood pressure were recorded every fortnightly for three months. At the end of the trial, animals were killed and measurement of plasma total antioxidant status, plasma superoxide dismutase (SOD) activity and lipid peroxide levels in plasma and blood vessels were carried out following well established methods. Study shows that lipid peroxides were significantly higher in hypertensive plasma and blood vessels compared to that of normal rats (Plasma- N: 0.06+/-0.01, HC: 0.13+/-0.008; p<0.001, B1. Vessels - N: 0.47+/-0.17, HC: 0.96+/-0.37; p<0.001). SOD activity was significantly lower in hypertensive than normal rats (N = 148.58+/-29.56 U/ml, HC = 110.08+/-14.36 U/ml; p = 0.014). After three months of antioxidant trial with gamma-tocotrienol, it was found that all the treated groups have reduced plasma lipid peroxides concentration but was only significant for group gamma1 (gamma1: 0.109+/-0.026, HC: 0.132+/-0.008; p = 0.034). On the other hand, lipid peroxides in blood vessels reduced significantly in all treated groups (gamma1; p<0.05, gamma2; p<0.001, gamma3; p<0.005). All the three treated groups showed improve total antioxidant status (p<0.001) significantly. SOD activity also showed significant improvement in all groups (gamma1: p<0.001, gamma2: p<0.05, gamma3: p<0.001). Correlation studies showed that, total antioxidant status (TAS) and SOD were significantly negatively correlated with blood pressure in normal rats (p = 0.007; p = 0.008) but not in SHR control. This correlation regained in all three groups SHR's after treatment with tocotrienol. Lipid peroxides in blood vessel and plasma showed a positive correlation with blood pressure in normal and SHR control. This correlation also remains in treated groups significantly except that in gamma3 where positive correlation with plasma lipid peroxide was not significant. In conclusion it was found that antioxidant supplement of gamma-tocotrienol may prevent development of increased blood pressure, reduce lipid peroxides in plasma and blood vessels and enhanced total antioxidant status including SOD activity.
    Matched MeSH terms: Antioxidants/metabolism*
  12. Cheah PB, Gan SP
    J Food Prot, 2000 Mar;63(3):404-7.
    PMID: 10716573
    The antioxidant and microbial stabilities of galangal (Alpinia galanga) extract in raw minced beef were examined at 4 +/- 1 degree C. Raw minced beef containing galangal extracts (0 to 0.10%, wt/wt) were prepared. Lipid oxidation during refrigerated storage was assessed by monitoring malonaldehyde formation, using the thiobarbituric acid reactive substances method. In minced beef, added galangal extract improved oxidative stability. Galangal extract at higher concentrations of 0.05% and 0.10% (wt/wt) were also found to extend the shelf-life of minced beef. Addition of alpha-tocopherol (0.02%, wt/wt) to galangal extract (0.05%, wt/wt) were observed to increase the oxidative but not the microbial stability of minced beef during the storage of 7 days. Galangal extract may prove useful in inhibiting lipid oxidation and increasing microbial stability of minced meat.
    Matched MeSH terms: Antioxidants/pharmacology*
  13. Habsah M, Amran M, Mackeen MM, Lajis NH, Kikuzaki H, Nakatani N, et al.
    J Ethnopharmacol, 2000 Oct;72(3):403-10.
    PMID: 10996279
    Dichloromethane and methanol extracts of 13 Zingiberaceae species from the Alpinia, Costus and Zingiber genera were screened for antimicrobial and antioxidant activities. The antimicrobial activity of most of the extracts was antibacterial with only the methanol extract of Costus discolor showing very potent antifungal activity against only Aspergillus ochraceous (MID, 15.6 microg per disc). All the extracts showed strong antioxidant activity comparable with or higher that of alpha-tocopherol.
    Matched MeSH terms: Antioxidants/pharmacology*
  14. Ismail M, Manickam E, Danial AM, Rahmat A, Yahaya A
    J Nutr Biochem, 2000 Nov;11(11-12):536-542.
    PMID: 11137889
    This study investigated the components present in and the total antioxidant activity of leaves of Strobilanthes crispus (L.) Bremek or Saricocalyx crispus (L.) Bremek (Acanthacea). Proximate analyses and total antioxidant activity using ferric thiocyanate and thiobarbituric acid methods were employed. Minerals content was determined using the atomic absorption spectrophotometer, whereas the water-soluble vitamins were determined by means of the UV-VIS spectrophotometer (vitamin C) and fluorimeter (vitamins B(1) and B(2)). Catechin, tannin, caffeine, and alkaloid contents were also studied. All data were compared to the previously reported results of Yerbamate, green tea, black tea, and Indian tea. The dried leaves contained a high amount of total ash (21.6%) as a result of a high amount of minerals including potassium (51%), calcium (24%), sodium (13%), iron (1%), and phosphorus (1%). High content of water-soluble vitamins (C, B(1), and B(2)) contributed to the high antioxidant activity of the leaves. The leaves also contained a moderate amount of other proximate composition as well as other compounds such as catechins, alkaloids, caffeine, and tannin, contributing further to the total antioxidant activity. Catechins of Strobilanthes crispus leaves showed highest antioxidant activity when compared to Yerbamate and vitamin E. Consumption of the leafy extract daily (5 g/day) as an herbal tea could contribute to the additional nutrients and antioxidants needed in the body to enhance the defense system, especially toward the incidence of degenerative diseases.
    Matched MeSH terms: Antioxidants
  15. Yap SP, Yuen KH, Wong JW
    J Pharm Pharmacol, 2001 Jan;53(1):67-71.
    PMID: 11206194
    We have investigated the pharmacokinetics and bioavailability of alpha-, gamma- and delta-tocotrienols under fed and fasted conditions in eight healthy volunteers. The volunteers were administered a single oral dose of mixed tocotrienols (300 mg) under fed or fasted conditions. The bioavailability of tocotrienols under the two conditions was compared using the parameters peak plasma concentration (Cmax), time to reach peak plasma concentration (Tmax) and total area under the plasma concentration-time curve (AUC(o-infinity)). A statistically significant difference was observed between the fed and fasted logarithmic transformed values of Cmax (P < 0.01) and AUC(0-infinity) (P < 0.01) for all three tocotrienols. In addition, the 90% confidence intervals for the ratio of the logarithmic transformed AUC(0-infinity) values of alpha-, gamma- and delta-tocotrienols under the fed state over those of the fasted state were found to lie between 2.24-3.40, 2.05-4.09 and 1.59-3.81, respectively, while those of the Cmax were between 2.28-4.39, 2.31-5.87 and 1.52-4.05, respectively. However, no statistically significant difference was observed between the fed and fasted Tmax values of the three homologues. The mean apparent elimination half-life (t(1/2)) of alpha-, gamma- and delta-tocotrienols was estimated to be 4.4, 4.3 and 2.3 h, respectively, being between 4.5- to 8.7-fold shorter than that reported for alpha-tocopherol. No statistically significant difference was observed between the fed and fasted t(1/2) values. The mean apparent volume of distribution (Vd/f) values under the fed state were significantly smaller than those of the fasted state, which could be attributed to increased absorption of the tocotrienols in the fed state.
    Matched MeSH terms: Antioxidants/pharmacokinetics*
  16. Rahmat A, Seam CK, Endrini S, Mansor SM
    Malays J Med Sci, 2001 Jan;8(1):41-5.
    PMID: 22973155
    Milk is a physiological fluid which has high nutritional value and soybean has strong antioxidant characteristics which is believed to inhibit carcinogenesis. The objective of this study was to investigate the effects of administration of soybean and goat's milk on hepatocarcinogenesis in rats (fed with diethylnitrosamine; DEN and acetylaminofluorene; AAF) by determining the activities of plasma gamma-glutamyl transpeptidase (GGT) and alkaline phosphatase (ALP). Thirty-six rats from the species Sprague-Dawley were divided into 6 groups : control, DEN/AAF, soybean, DEN/AAF with soybean treatment, goat's milk and DEN/AAF with goat's milk treatment. Soybean and goat's milk administrations were given 5 ml/day. The rats were sacrificed after 8 weeks and the blood was collected. Treatment with DEN/AAF caused an increase in ALP and GGT levels and a decrease in weight significantly (p<0.05). ALP and GGT activities decreased significantly after administration of soybean and goat's milk (p<0.05). Administration of goat's milk and soybean alone did not cause any changes in the enzyme activities. Comparison between the effect of soybean and goat's milk in reducing the enzyme activities (ALP and GGT) did not give significant values (p>0.05). However, a decrease in weight was observed in the rats given soybean as well as goat's milk. The results obtained suggested that soybean and goat's milk may work as anti cancer agents in hepatocarcinogenesis although further studies are required to further elucidate this aspect.
    Matched MeSH terms: Antioxidants
  17. Nafeeza MI, Norzana AG, Jalaluddin HL, Gapor MT
    Malays J Pathol, 2001 Jun;23(1):17-25.
    PMID: 16329543
    This study investigated the effects of a tocotrienol-rich fraction (TTRF) on the microscopic development of atherosclerosis and lipid peroxidation in the aorta of rabbits. Group 1 was fed a normal diet, group 2 received a 2% cholesterol diet and group 3 received a 2% cholesterol diet plus daily oral administration of the TTRF. After 10 weeks, the aortic content of malondialdehyde (MDA) was measured as an index of lipid peroxidation. The MDA was lowest in rabbits that received the TTRF compared to the groups that did not. The degree of intimal thickening was higher in the cholesterol-fed rabbits without the TTRF compared to the cholesterol-fed rabbits with TTRF (P<0.05). The continuity of the internal elastic lamina (IEL) was noted to be preserved in the cholesterol-fed rabbits with TTRF but appeared disrupted in the cholesterol-fed rabbits without the TTRF. The disrupted and fragmented IEL may have resulted from the injury caused by lipid peroxidation that contributed to the more extensive intimal thickening. We conclude that the antioxidant activities of the TTRF can reduce experimental atherosclerosis.
    Matched MeSH terms: Antioxidants/therapeutic use*
  18. Inayat-Hussain SH, Osman AB, Din LB, Taniguchi N
    Toxicol Lett, 2002 May 28;131(3):153-9.
    PMID: 11992734
    Plant styryl-lactone derivatives isolated from Goniothalamus sp. are potential compounds for cancer chemotherapy. In this study, we have examined the mechanisms of apoptosis induced by altholactone, a stryl-lactone isolated from the Malaysian plant G. malayanus on human HL-60 promyelocytic leukemia cells. Flow cytometric analysis of the externalization of phosphatidylserine (PS) using the annexin V/PI method on altholactone treated HL-60 cells showed a concentration-dependent increase of apoptosis from concentrations ranging from 10.8 (2.5 microg/ml) to 172.4 microM (40 microg/ml). Pre-treatment with the antioxidant N-acetylcysteine (1 mM) completely abrogated apoptosis induced by altholactone, suggesting for the involvement of oxidative stress. Further flow cytometric assessment of the level of intracellular peroxides using the fluorescent probe 2',7'-dichlorofluorescein diacetate (DCFH-DA) confirmed that altholactone induced an increase in cellular oxidative stress in HL-60 cells which was suppressed by N-acetylcysteine. In summary, our results demonstrate for the first time that altholactone induced apoptosis in HL-60 cells occurs via oxidative stress.
    Matched MeSH terms: Antioxidants/pharmacology
  19. Salleh MN, Runnie I, Roach PD, Mohamed S, Abeywardena MY
    J Agric Food Chem, 2002 Jun 19;50(13):3693-7.
    PMID: 12059144
    Twelve edible plant extracts rich in polyphenols were screened for their potential to inhibit oxidation of low-density lipoprotein (LDL) in vitro and to modulate LDL receptor (LDLr) activity in cultured HepG2 cells. The antioxidant activity (inhibition of LDL oxidation) was determined by measuring the formation of conjugated dienes (lag time) and thiobarbituric acid reagent substances (TBARS). Betel leaf (94%), cashew shoot (63%), Japanese mint (52%), semambu leaf (50%), palm frond (41%), sweet potato shoot, chilli fruit, papaya shoot, roselle calyx, and maman showed significantly increased lag time (>55 min, P < 0.05) and inhibition of TBARS formation (P < 0.05) compared to control. LDLr was significantly up-regulated (P < 0.05) by Japanese mint (67%), semambu (51%), cashew (50%), and noni (49%). Except for noni and betel leaf, most plant extracts studied demonstrated a positive association between antioxidant activity and the ability to up-regulate LDL receptor. Findings suggest that reported protective actions of plant polyphenols on lipoprotein metabolism might be exerted at different biochemical mechanisms.
    Matched MeSH terms: Antioxidants/pharmacology*
  20. Norazlina M, Ima-Nirwana S, Abul Gapor MT, Abdul Kadir Khalid B
    Asia Pac J Clin Nutr, 2002;11(3):194-9.
    PMID: 12230232
    In this study the effects of vitamin E deficiency and supplementation on bone calcification were determined using 4-month-old female Sprague-Dawley rats. The rats weighed between 180 and 200 g. The study was divided in three parts. In experiment I the rats were given normal rat chow (RC, control group), a vitamin E deficient (VED) diet or a 50% vitamin E deficient (50%VED) diet. In experiment 2 the rats were given VED supplemented with 30 mg/kg palm vitamin E (PVE30), 60 mg/kg palm vitamin E (PVE60) or 30 mg/kg pure alpha-tocopherol (ATF). In experiment 3 the rats were fed RC and given the same supplements as in experiment 2. The treatment lasted 8 months. Vitamin E derived from palm oil contained a mixture of ATF and tocotrienols. Rats on the VED and 50%VED diets had lower bone calcium content in the left femur compared to the RC group (91.6 +/- 13.3 mg and 118.3 +/- 26.0 mg cf 165.7 +/- 15.2 mg; P < 0.05) and L5 vertebra (28.3 +/- 4.0 mg and 39.5 +/- 6.2 mg compared with 51.4 +/- 5.8 mg; P < 0.05). Supplementing the VED group with PVE60 improved bone calcification in the left femur (133.6 +/- 5.0 mg compared with 91.6 +/- 13.3 mg; P < 0.05) and L5 vertebra (41.3 +/- 3.3 mg compared with 28.3 +/- 4.0 mg; P < 0.05) while supplementation with PVE30 improved bone calcium content in the L5 vertebra (35.6 +/- 3.1 mg compared with 28.3 +/- 4.0 mg; P < 0.05). However, supplementation with ATF did not change the lumbar and femoral bone calcium content compared to the VED group. Supplementing the RC group with PVE30, PVE60 or ATF did not cause any significant changes in bone calcium content. In conclusion, vitamin E deficiency impaired bone calcification. Supplementation with the higher dose of palm vitamin E improved bone calcium content, but supplementation with pure ATF alone did not. This effect may be attributed to the tocotrienol content of palm vitamin E. Therefore, tocotrienols play an important role in bone calcification.
    Matched MeSH terms: Antioxidants/administration & dosage; Antioxidants/metabolism*
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