Effect of tocotrienol on the activities of cytosolic glutathione-dependent enzymes in rats treated with 2-acetylaminofluorene

Shamaan, Nor Aripin; Ngah, Wan Zurinah Wan; Ibrahim, Rusli; Jarien, Zanariah; Top, Abdul Gapor Md; Kadir, Khalid Abdul

doi:10.1016/0006-2952(93)90052-x

Cited by 12 publications

(6 citation statements)

References 11 publications

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“…Significant GR activation was detected in all tissues of tetrachlorobiphenyl-injected trout in this study ( fig. 2), confirming similar results in rodents after PCB or other toxicant exposures (Kamohara et al 1984;Shamaan et al 1993).…”

Section: Discussionsupporting

confidence: 78%

“…These results are in contrast to studies using rats fed PCB containing diets for short and long durations which reported significantly decreased hepatic GPX activities (Kamohara et al 1984;Saito 1990). In other studies, however, rat GPX activity remained unchanged after injection with different PCB congeners, while administration of various other compounds including isosafrole, phenobarbital or 2-acetylaminofluorene resulted in significantly increased GPX activities (Schramm et al 1985;Shamaan et al 1993). Short-and long-term exposures of different fish species to PCB mixtures resulted in increased lipid peroxidation within liver, muscles and ovarian tissues (Thomas & Wofford 1993;Rudneva-Titova & Zherko 1994).…”

Section: Discussioncontrasting

confidence: 72%

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3,3′,4,4′‐Tetrachlorobiphenyl Effects on Antioxidant Enzymes and Glutathione Status in Different Tissues of Rainbow Trout

Otto

Moon

1995

Pharmacology & Toxicology

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Polychlorinated biphenyls are known to cause induction in cytochrome P450-dependent monooxygenase activities and alteration in the antioxidant defense of mammals. To determine whether similar detoxication processes are activated in rainbow trout (Oncorhynchus mykiss), we investigated P450-dependent enzyme activities, antioxidant enzymes and glutathione status (reduced and oxidized glutathione, GSH and GSSG) in this species injected intraperitoneally with 3,3',4,4'-tetrachlorobiphenyl at 5 mg/kg body weight 6 weeks post injection. Ethoxyresorufin O-deethylase activities increased 11- and 40-fold in liver and kidney. UDPglucuronosyltransferase activities were 2- and 5-fold higher in these organs, while glutathione S-transferase activity was enhanced greater than 2-fold in liver of tetrachlorobiphenyl injected trout in comparison with controls. Glutathione peroxidase activities were increased in liver and white muscle of dosed fish. Tetrachlorobiphenyl exposure resulted in a significant increase in glutathione reductase activities, with 7-fold enhancement in liver and significantly elevated activities in kidney, red and white muscles. Similarly, cytosolic superoxide dismutase and catalase activities were increased in white muscle of injected trout. Tetrachlorobiphenyl exposure significantly increased GSH concentrations in liver and kidney, while GSSG levels were increased in liver and blood plasma. These changes, however, did not modify the GSSG/GSH ratios in these tissues. Overall, these results imply a major tetrachlorobiphenyl effect on GSH status and antioxidant enzymes in trout tissues and identify white muscle along with liver and kidney as important tissues in the detoxication process in this animal.

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Section: Discussionsupporting

confidence: 78%

Section: Discussioncontrasting

confidence: 72%

3,3′,4,4′‐Tetrachlorobiphenyl Effects on Antioxidant Enzymes and Glutathione Status in Different Tissues of Rainbow Trout

Otto

Moon

1995

Pharmacology & Toxicology

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“…Expression of biomarkers of liver carcinogenesis such as glutathione, alkaline phosphatase, and gamma-glutamyl transpeptidase was enhanced by the carcinogens but attenuated by tocotrienols, decreasing the impact of the carcinogens. A similar study by others confirmed these findings [110]. All these studies suggest that tocotrienols have potential to both prevent and treat cancer.…”

Section: Animal Studies With Tocotrienolssupporting

confidence: 79%

Tocotrienols, the vitamin E of the 21st century: Its potential against cancer and other chronic diseases

Aggarwal

Sundaram

Prasad

et al. 2010

Biochemical Pharmacology

497

382

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Initially discovered in 1938 as a "fertility factor," vitamin E now refers to eight different isoforms that belong to two categories, four saturated analogues (α, β, γ, and δ) called tocopherols and four unsaturated analogues referred to as tocotrienols. While the tocopherols have been investigated extensively, little is known about the tocotrienols. Very limited studies suggest that both the molecular and therapeutic targets of the tocotrienols are distinct from those of the tocopherols. For instance, suppression of inflammatory transcription factor NF-κB, which is closely linked to tumorigenesis and inhibition of HMG-CoA reductase, mammalian DNA polymerases and certain protein tyrosine kinases, is unique to the tocotrienols. This review examines in detail the molecular targets of the tocotrienols and their roles in cancer, bone resorption, diabetes, and cardiovascular and neurological diseases at both preclinical and clinical levels. As disappointment with the therapeutic value of the tocopherols grows, the potential of these novel vitamin E analogues awaits further investigation.

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“…lntragastric administration of tocotrienol for 30 days caused a significant elevation in different components of hepatic antioxidant defence and reduction in serum enzymes of hepatic damage in rats fed with 2-acetylaminofluorene (AAF) [ 113 ]. Shamaan et al [ 114 ] investigated the effect of tocotrienol on the activities of glutathione S-transferases (GSTs), glutathione reductase (GR) and glutathione peroxidase (GPx) in rats given 2-acetylaminofluorene (AAF) over a 20 week period. Liver and kidney GST and liver GR activities were significantly increased after AAF administration.…”

Section: Pharmacological Propertiesmentioning

confidence: 99%

Pharmacological potential of tocotrienols: a review

et al. 2014

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Tocotrienols, members of the vitamin E family, are natural compounds found in a number of vegetable oils, wheat germ, barley, and certain types of nuts and grains. Like tocopherols, tocotrienols are also of four types viz. alpha, beta, gamma and delta. Unlike tocopherols, tocotrienols are unsaturated and possess an isoprenoid side chain. Tocopherols are lipophilic in nature and are found in association with lipoproteins, fat deposits and cellular membranes and protect the polyunsaturated fatty acids from peroxidation reactions. The unsaturated chain of tocotrienol allows an efficient penetration into tissues that have saturated fatty layers such as the brain and liver. Recent mechanistic studies indicate that other forms of vitamin E, such as γ-tocopherol, δ-tocopherol, and γ-tocotrienol, have unique antioxidant and anti-inflammatory properties that are superior to those of α-tocopherol against chronic diseases. These forms scavenge reactive nitrogen species, inhibit cyclooxygenase- and 5-lipoxygenase-catalyzed eicosanoids and suppress proinflammatory signalling, such as NF-κB and STAT. The animal and human studies show tocotrienols may be useful against inflammation-associated diseases. Many of the functions of tocotrienols are related to its antioxidant properties and its varied effects are due to it behaving as a signalling molecule. Tocotrienols exhibit biological activities that are also exhibited by tocopherols, such as neuroprotective, anti-cancer, anti-inflammatory and cholesterol lowering properties. Hence, effort has been made to compile the different functions and properties of tocotrienols in experimental model systems and humans. This article constitutes an in-depth review of the pharmacology, metabolism, toxicology and biosafety aspects of tocotrienols. Tocotrienols are detectable at appreciable levels in the plasma after supplementations. However, there is inadequate data on the plasma concentrations of tocotrienols that are sufficient to demonstrate significant physiological effect and biodistribution studies show their accumulation in vital organs of the body. Considering the wide range of benefits that tocotrienols possesses against some common human ailments and having a promising potential, the experimental analysis accounts for about a small fraction of all vitamin E research. The current state of knowledge deserves further investigation into this lesser known form of vitamin E.Electronic supplementary materialThe online version of this article (doi:10.1186/1743-7075-11-52) contains supplementary material, which is available to authorized users.

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Effect of tocotrienol on the activities of cytosolic glutathione-dependent enzymes in rats treated with 2-acetylaminofluorene

Cited by 12 publications

References 11 publications

3,3′,4,4′‐Tetrachlorobiphenyl Effects on Antioxidant Enzymes and Glutathione Status in Different Tissues of Rainbow Trout

3,3′,4,4′‐Tetrachlorobiphenyl Effects on Antioxidant Enzymes and Glutathione Status in Different Tissues of Rainbow Trout

Tocotrienols, the vitamin E of the 21st century: Its potential against cancer and other chronic diseases

Pharmacological potential of tocotrienols: a review

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