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PubMed1980

Effects of ergothioneine, cysteine, and glutathione on nitrosation of secondary amines under physiologic conditions.

The effects of ergothioneine, cysteine, and glutathione, which are naturally occurring sulfhydryl compounds, on the aerobic and anaerobic nitrosation of dimethylamine were studied at pH 2.0-7.0 and at 37 degrees C. Under aerobic conditions, ergothioneine increased the formation of dimethylnitrosamine (DMN) at all pH values tested, cysteine and glutathione had the same effect at pH 4.0-6.0, and cysteine formed DMN at pH 7.0. However, as compared to controls cysteine showed no increased effect in an O2 atmosphere at pH 6.0. The effects of sulfhydryl compounds on anaerobic nitrosation were more significant (p < 0.001) than on aerobic nitrosation, probably because these sulfhydryl compounds, except ergothioneine, are easily oxidized. Ergothioneine increased aerobic nitrosation almost as strongly as anaerobic nitrosation. The effects of sulfhydryl compounds, especially ergothioneine, on nitrosation at physiologic pH and temperature might be significant in the in vivo formation of N-nitrosamines in the hemorrhage or ulcerous gastrointestinal tract or injured organs.

Animals↗

PubMed1993

Stability and nonreactivity of ergothioneine in human erythrocytes studied by 1H NMR.

The N(CH3)3 resonance of ergothioneine in 1H spin-echo Fourier transform (SEFT) NMR spectra of red blood cells is usually a large singlet and it has been common practice to use this apparently unchanging resonance as an intensity reference. Recently, Reglinski et al. (Magn. Reson. Med. 6, 217-223 (1988)) have questioned this practice, reporting changes seen in the resonance in response to oxidative stress induced by arsenicals. We propose that the changes in the ergothioneine resonance that were reported are artifacts due to alterations in osmolality and magnetic susceptibility induced by the addition of nonisotonic solutions to red blood cell suspensions. These factors change the specific intensity of the intracellular resonances of all compounds. Ergothioneine was observed not to take part in any chemical reactions with arsenicals in free solution or in intact erythrocytes, and we conclude that ergothioneine may still be used as an internal intensity reference in 1H SEFT NMR spectra, bearing in mind the above physical factors.

Artifacts↗

PubMed1991

The antioxidant action of ergothioneine.

Ergothioneine is a product of plant origin that accumulates in animal tissues. Its suggested ability to act as an antioxidant has been evaluated. Ergothioneine is a powerful scavenger of hydroxyl radicals (.OH) and an inhibitor of iron or copper ion-dependent generation of .OH from hydrogen peroxide (H2O2). It is also an inhibitor of copper ion-dependent oxidation of oxyhaemoglobin, and of arachidonic acid peroxidation promoted by mixtures of myoglobin (or haemoglobin) and H2O2. Ergothioneine is a powerful scavenger of hypochlorous acid, being able to protect alpha 1-antiproteinase against inactivation by this molecule. By contrast, it does not react rapidly with superoxide (O2-) or hydrogen peroxide (H2O2) and it does not inhibit microsomal lipid peroxidation in the presence of iron ions. Overall, our results show that ergothioneine at the concentrations present in vivo could act as an antioxidant.

Animals↗

PubMed1966

The presence of ergothioneine in the central nervous system and its probable identity with the cerebellar factor.

1. Ergothioneine has been detected and quantitatively estimated in the brains of mice, rats, guinea-pigs, rabbits, cats and sheep. It is present in the cerebellum in amounts ranging from about 3.0 mug/g in the cat to 10 mug/g in the guinea-pig. Amounts in the cerebral hemispheres are much smaller, ranging from < 0.1 mug/g in the cat to 1.6 mug/g in the guinea-pig.2. Large amounts of ergothioneine (about 30 mug/g) were found in the optic nerves of the rabbit. None was detected in the dorsal columns of the spinal cord of the same species.3. Ergothioneine has an excitatory action on the electrical activity of the cerebellum of the decerebrate rabbit and the excitatory actions of cerebellar extracts on this preparation are completely accounted for by their contained ergothioneine.4. It is concluded that the cerebellar factor of Crossland & Mitchell (1956) is identical with ergothioneine.

Animals↗

PubMed1968

Biosynthesis of ergothioneine from endogenous hercynine in Mycobacterium smegmatis.

Ergothioneine was synthesized and accumulated in growing cultures of Mycobacterium smegmatis when the medium was adequately supplied with sulfur. In a low sulfur medium, the accumulation was sharply limited although growth of the organism was apparently normal. Synthesis of hercynine, the precursor of ergothioneine, was unaffected by low sulfur levels and was markedly increased by addition of l-histidine, the precursor of hercynine. Resting-cell pellicle experiments, performed with cells grown on the low sulfur high histidine medium, showed that ergothioniene was synthesized from endogenous hercynine, when cysteine or compounds readily converted to cysteine (such as cystine, lanthionine, cystathionine, and thiazolidine carboxylic acid) were added. Homocysteine and djenkolic acid allowed for minimal synthesis of betaine, whereas methionine, S-methylcysteine, sodium sulfate, and sodium thiosulfate were unable to donate sulfur for ergothioniene synthesis under the experimental conditions employed. Addition of cysteine to a resting pellicle preparation caused the formation of 100 to 200 mug of ergothioneine per g of dry cells in 2.5 to 3 hr. A modified procedure for isolating ergothioneine and hercynine, employing a 75% ethyl alcohol extraction of wet organisms, followed by a single alumina column separation of the compounds, is described.

Betaine↗

PubMed1992

Possible mechanism of inhibition of nitrite-induced oxidation of oxyhemoglobin by ergothioneine and uric acid.

The time course of oxyhemoglobin oxidation by nitrite consisted of a kinetic lag followed by a transition phase which progressed into a rapid autocatalytic phase. The imidazolthione and imidazolone derivatives, ergothioneine and uric acid, respectively, caused an increase in the duration of the lag phase in a concentration-dependent manner, without affecting the onset and rate of the autocatalytic phase. Neither compound reacted with H2O2 or nitrite, oxidizing species required in the initiation steps of oxyhemoglobin oxidation. On the other hand, both compounds reduced effectively and at comparable rates the high oxidation state of hemoglobin, i.e., ferrylhemoglobin, which is an intermediate species occurring in the autocatalytic phase. In addition, the rate of ergothioneine oxidation, upon its reaction with ferrylmyoglobin, was accelerated by nitrite, thus suggesting a reaction between the thione and nitrogen dioxide. Nitrogen oxide and ferrylhemoglobin are key species in the free radical chain propagation leading to oxyhemoglobin oxidation by nitrite. These data support the view that ergothioneine and urate delay oxyhemoglobin oxidation by nitrite upon the temporary removal of the propagating species, i.e., nitrogen dioxide and, secondarily, ferrylhemoglobin, and within a mechanism encompassing alterations of the nitrite in equilibrium with nitrogen dioxide and ferrylhemoglobin in equilibrium with methemoglobin redox transitions.

Adult↗

PubMed2001

L-ergothioneine level in red blood cells of healthy human males in the Western province of Saudi Arabia.

Ergothioneine is widely distributed in biological systems, particularly in red blood cells of animals. However, it's functional role in human body is not well understood. In order to investigate the biochemical effect of L-ergothioneine, its concentration changes in human blood with respect to ages in healthy individuals was first investigated. L-ergothioneine concentrations in the blood of Saudi males from western province at different stages of life were measured by the procedure of Carlsson et al., 1974. At early stages of life (1-10 years), the concentrations of LER is 1.5-2.0 mg/100 ml. It increases gradually at the age of 11-18 years where it reaches the maximum value of 3.7 mg/100 ml. Then, it declines gradually to 3.0-2.3 mg/ 100 ml during the period of 19-50 years. An increase in the level of LER (2.8 mg/100 ml) was seen at the age of 51+.

Adolescent↗

PubMed1974

A convenient spectrophotometric assay for the determination of L-ergothioneine in blood.

1. A convenient spectrophotometric assay for the determination of l-ergothioneine in solution including deproteinized blood haemolysate was developed. 2. The method consists of deproteinization by heat precipitation and Cu(2+)-catalysed oxidation of thiols such as glutathione and of l-ascorbic acid, both in alkaline media, and titration of l-ergothioneine (which is not oxidized under these conditions) by its virtually instantaneous reaction with 2,2'-dipyridyl disulphide at pH1. 3. This method and the results obtained with it for the analysis of human, horse, sheep and pig blood are compared with existing methods of l-ergothioneine analysis and the results obtained thereby.

Animals↗

PubMed2005

beta-Hydroxyergothioneine, a new ergothioneine derivative from the mushroom Lyophyllum connatum, and its protective activity against carbon tetrachloride-induced injury in primary culture hepatocytes.

A new ergothioneine derivative named beta-hydroxyergothioneine was isolated from the mushroom Lyophyllum connatum. Ergothioneine,N-hydroxy-N',N'-dimethylurea, and connatin (N-hydroxy-N',N'-dimethylcitrulline) were also isolated. All the compounds displayed the ability to scavenge free radicals, based on a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. Structural determination, including the absolute stereochemistry of beta-hydroxyergothioneine, was achieved by spectroscopic analysis and X-ray crystallography. The radical scavenging activity of beta-hydroxyergothioneine was almost the same as that of ergothioneine. beta-Hydroxyergothioneine showed the greatest protective activity against carbon tetrachloride-induced injury in primary culture hepatocytes.

Agaricales↗

PubMed1963

DEGRADATION OF ERGOTHIONEINE BY CELL-FREE EXTRACTS OF ALCALIGENES FAECALIS. II. PRODUCTION OF GLUTAMIC ACID.

Booth, James S. (University of Southern California, Los Angeles) and Milo D. Appleman. Degradation of ergothioneine by cell-free extracts of Alcaligenes faecalis. II. Production of glutamic acid. J. Bacteriol. 85:654-657. 1963.-On the basis of oxidation and paper chromatographic procedures, glutamic acid was identified as the end product of ergothioneine degradation by cell-free extracts of Alcaligenes faecalis. Hydrogen sulfide and ammonia yields were determined. Several differences between the metabolism of whole cells and cell-free extracts were noted. Cleavage of the imidazole ring by cell-free extracts appeared to be hydrolytic rather than oxidative.

Alcaligenes↗

PubMed2006

Activity of the dietary antioxidant ergothioneine in a virus gene-based assay for inhibitors of HIV transcription.

The "Long Terminal Repeat" (LTR) of HIV-1 is the target of cellular transcription factors such as NF-kappaB, and serves as the promoter-enhancer for the viral genome when integrated in host DNA. Various LTR-reporter gene constructs have been used for in vitro studies of activators or inhibitors of HIV-1 transcription, e.g., to show that antioxidants such as lipoic acid and selenium inhibit NF-kappaB-dependent HIV-1 LTR activation. One such construct is the pHIVlacZ plasmid, with the HIV-1 LTR driving expression of the lacZ gene (encoding beta-galactosidase, beta-gal). Typically, for inhibitor screening, cells transfected with pHIVlacZ are activated using tumor necrosis factor-alpha (TNF-alpha), and the colorimetric o-nitrophenol assay is used to assess changes in beta-gal activity. A variant of this assay was developed as described here, in which LTR activation was induced by pro-fs, a novel HIV-1 gene product encoded via a -1 frameshift from the protease gene. Cotransfection of cells with pHIVlacZ along with a pro-fs construct produced a significant increase in beta-gal activity over controls. L-ergothioneine dose dependently inhibited both TNF-alpha-mediated and pro-fs-mediated increases in beta-gal activity, with an IC50 of about 6 mM. Thus antioxidant strategy involving ergothioneine derived from food plants might be of benefit in chronic immunodeficiency diseases.

Animals↗

PubMed1988

Spin-echo 1H NMR detected response of ergothioneine to oxidative stress in the intact human erythrocyte.

Human erythrocytes were subjected to oxidative stress using arsenicals. The study is a model for thiol-related redox processes observed in the etiology of diseases such as rheumatoid arthritis. Spin-echo NMR spectroscopy of the living cell was used to monitor the cellular biochemistry. Oxidation of glutathione and the first demonstrated response of ergothioneine to a chemical stimulus in a cell were observed. The reversible nature of the ergothioneine response is interpreted as an environmental rather than a chemical change.

Arthritis, Rheumatoid↗

PubMed1997

Antioxidant action of ergothioneine: assessment of its ability to scavenge peroxynitrite.

The superoxide radical (O.2-) and nitric oxide (NO.) combine very rapidly to form peroxynitrite (ONOO-), a reactive tissue damaging nitrogen species thought to be involved in the pathology of several chronic diseases. The natural product ergothioneine protects against the nitration of tyrosine and the inactivation of alpha 1-antiproteinase by ONOO-. Ergothioneine merits further investigation as a biological and therapeutic antioxidant agent.

Antioxidants↗

PubMed2004

Ergothioneine pretreatment protects the liver from ischemia-reperfusion injury caused by increasing hepatic heat shock protein 70.

BACKGROUND: Reperfusion of the liver after ischemia induces the expression of the heat shock genes and the synthesis of the heat shock proteins (HSP). We studied the effects of the natural antioxidant ergothioneine (EGT) treatment on the expression of HSP70 in ischemic-reperfused (IR) liver. METHODS: Adult male Wistar rats were randomly divided into three groups: Sham group given standard laboratory chow and water for 3 weeks followed by sham operation; Control group given standard laboratory chow and water for 3 weeks followed by liver IR injury; EGT group given standard laboratory chow supplementation l-ergothioneine (1.2 mg/kg/d body weight) administered by gavage and water for 3 weeks followed by liver IR injury. Ten rats from each group were killed to determine serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactic dehydrogenase (LDH), tissue malondialdehyde (MDA), HSP70 levels, and histologic changes at 30, 60, and 120 min of reperfusion, respectively. Survival was followed for 1 week. RESULTS: IR caused significant increase in serum AST, ALT, LDH, and tissue MDA levels. As compared with the control group, animals treated with EGT experienced a significant decrease in serum AST, ALT, and LDH levels in all reperfusion periods. Tissue MDA levels in animals receiving EGT were significantly reduced as compared with control group at 30 min and 60 min after reperfusion. After ischemia, reperfusion caused a remarkable production of HSP70 in the control group. When the rats were pretreated with EGT, the levels of HSP70 increased significantly in their livers after reperfusion compared with the control group. Liver injury in the EGT-treated animals was lower to that in the control group. The 7-day survival rate was significantly improved (from 50% to 80%) by EGT pretreatment. CONCLUSION: HSP70 has been shown to induce tolerance against warm IR injury in rat livers. EGT pretreatment protects the liver from IR injury by over-expression of HSP and the subsequent suppression of lipid peroxidation.

Alanine Transaminase↗

PubMed1999

Protection against oxidative damage and cell death by the natural antioxidant ergothioneine.

The natural antioxidant ergothioneine (EGT) was tested for its ability to inhibit cell death caused by hydrogen peroxide (H2O2) and to inhibit DNA oxidation by peroxynitrite (ONOO-) in human neuronal hybridoma cell line (N-18-RE-105). High concentrations of EGT (5 mM) were tolerated by the N-18-RE-105 cells. N-acetylcysteine (NAC) was not well tolerated by the cells at concentrations greater than 3 mM (cell viability averaged 50%). Increasing concentrations of EGT increases cell viability in the presence of NAC. EGT at concentrations up to 2 mM weakly improved cell viability in the presence of H2O2. NAC at concentrations up to 2 mM weakly decreased, but not significantly, the viability of the cells. At a higher concentration of 5 mM, NAC weakly protected the neuronal cells against the H2O2-induced cell death. The protection was significantly enhanced by preincubation with EGT. Ergothioneine inhibited ONOO(-)-induced oxidative damage in isolated calf thymus DNA and DNA in N-18-RE-105 cells. The concentration of EGT in human and mammalian tissue has been estimated to be 1-2 mM, which suggests that EGT may serve as a non-toxic thiol buffering antioxidant in vivo and may find applications in pharmaceutical preparations where oxidative stability is desired.

Animals↗

PubMed2002

Ergothioneine treatment protects neurons against N-methyl-D-aspartate excitotoxicity in an in vivo rat retinal model.

Injection of the glutamate agonist N-methyl-D-aspartate into the vitreous body of the rat eye resulted in a number of morphological changes in the retina. Most apparent was a dramatic reduction in the density and sizes of neurons accompanied by a decrease in amyloid precursor protein and glial fibrillary acidic protein immunoreactivity. Cell counts revealed that 81% of ganglion cells and 43% of non-ganglion cells were lost as a result of the treatment. However, in animals treated with the antioxidant ergothioneine, these figures dropped to 44 and 31%, respectively. Thus, ergothioneine appears to be neuroprotective in this system and the data suggest that antioxidants may provide a useful means of modulating glutamate-based toxicity.

Amyloid beta-Protein Precursor↗

PubMed1968

A new route to the imidazole-2-thiones from 2-thiohydantoins. Implications in the study of ergothioneine.

1. 2-Thiohydantoins are reduced by borohydrides to 4(5)-hydroxyimidazolidine-2-thiones, which eliminate water in acid to form imidazole-2-thiones. Both steps take place in mild conditions, in high yield. A number of imidazole-2-thiones have been synthesized by this sequence of steps, with one, two or three substituents in the 1-, 3- and 4(5)-positions. 2. 4(5)-Hydroxyimidazolidine-2-thiones are ammonium pseudo-bases, giving rise to an equilibrium mixture of amino aldehyde, carbinolamine and mesomeric ammonium cationic forms. The elimination of water is suggested to be a property of the mesomeric ammonium cation. 3. The mild conditions in which imidazole-2-thiones are formed from 4(5)-hydroxyimidazolidine-2-thiones are similar to those in which ergothioneine, a naturally occurring imidazole-2-thione of uncertain function, is normally released and measured. It is suggested that the occurrence in vivo of a precursor to ergothioneine, in the form of a 4(5)-hydroxyimidazolidine-2-thione, would explain many otherwise conflicting published data.

Aldehydes↗

PubMed1988

Ergothioneine, histidine, and two naturally occurring histidine dipeptides as radioprotectors against gamma-irradiation inactivation of bacteriophages T4 and P22.

Bacteriophages P22, T4+, and T4os (osmotic shock-resistant mutant with altered capsids) were diluted in 0.85% NaCl and exposed to gamma irradiation (2.79 Gy/min) at room temperature (24 degrees C). T4+ was more sensitive to inactivation than was P22, and the T4os mutant was even more sensitive than T4+. Catalase exhibited a strong protective effect and superoxide dismutase a weaker protection, indicating that H2O2 or some product derived therefrom was predominant in causing inactivation of plaque formation. Low but significant (0.1-0.3 mM) reduced glutathione (GSH) enhanced phage inactivation, but a higher (1 mM) GSH concentration protected. A similar effect was found for the polyamine, spermidine. In contrast, 0.1 mM L-ergothioneine (2-thiol-L-histidine betaine) exhibited strong protection and 1 mM afforded essentially complete protection. L-Ergothioneine is present in millimolar concentrations in some fungi and is conserved up to millimolar concentrations in critical tissues when consumed by man. L-Histidine and two histidine-containing dipeptides, carnosine and anserine, protected at a concentration of 1 mM, a level at which they are present in striated muscles of various animals.

Anserine↗