Preparative isolation of highly polar free radical inhibitor from Floccularia luteovirens using hydrophilic interaction chromatography directed by on-line HPLC-DPPH assay.

Wild edible macro fungi Floccularia luteovirens proved to be a valuable source for the identification of novel lead molecules with therapeutic potential. Nevertheless, the chemical constituents of Floccularia luteovirens are rarely reported due to absence of efficient purification methods. In this study, a hydrophilic interaction chromatography directed by on-line HPLC-DPPH assay has been developed and successfully applied for the isolation of free radical inhibitor from the methanolic extract of Floccularia luteovirens. Using a hydrophilic interaction chromatographic column coupled with the HPLC-DPPH assay for screening the potential radical scavengers, the mid-pressure hydrophilic interaction chromatography (HILIC) proved to be more efficient in the pretreatment stage, yielding the fraction rich in free radical scavengers in good yield (5.9% recovery from 130.0 g of fresh F. luteovirens). From highly potent fraction, the target compound was isolated using the Click XION preparative chromatography with 17.2% recovery. The isolated compound was L-(+)-ergothioneine, where the purity (>95%) and antioxidant activity of were confirmed by chromatography and HPLC-DPPH assay, while the structure of this compound was elucidated from HR ESI-MS and NMR data. This method proved to be very efficient for the recognition and isolation of highly polar free radical inhibitors from fungi extracts, and is also applicable for the purification of highly polar compounds from other sources.

Extraction of Ergothioneine from Pleurotus eryngii and P. citrinopileatus (Agaricomycetes) and Preparation of Its Product.

Ergothioneine is an effective antioxidant and is abundant in species of genus Pleurotus. This research focused on developing an ergothioneine extract from P. eryngii and P. citrinopileatus under optimal extraction conditions. The hot-water and 70% ethanol extractions yielded more ergothioneine than microwave, ultrasonic, and autoclaving extractions. Hot-water extraction with optimal conditions-125 rpm at 75°C for 5 minutes-produced P. eryngii and P. citrinopileatus extracts with 0.86 and 3.73 mg ergothioneine/g dry weight, respectively. In addition to 50% of added maltodextrin, spray-dried products from mushrooms contained 23.07-16.58% carbohydrates and 18.32-21.40% protein. The microstructure of spray-dried products showed shrunken spheres with mean particle diameters of 15.82-19.94 µm. After in vitro simulated gastric and intestinal digestion, the spray-dried P. eryngii and P. citrinopileatus products contained 88% and 91% residual ergothioneine, respectively. Overall, the spray-dried products could be used as antioxidative supplements.

A comprehensive screening shows that ergothioneine is the most abundant antioxidant in the wild macrofungus Phylloporia ribis Ryvarden.

The polar and non-polar extracts from the authenticated wild mushroom Phylloporia ribis were separated by hydrophilic interaction liquid chromatography (HILIC) and by reverse phase (RP)-HPLC, respectively. A split valve separated the eluents into two fractions for free-radical scavenging analysis and for structural identification. Forty-six compounds showed scavenging activity of the stable-free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). The structures of 8 antioxidants (inosine, caffeic acid, ergothioneine, p-hydroxybenzoic acid, adenosine, 3,4-dihydroxybenzaldehyde, apigenin, and naringenin) are characterized by Mass Spectrometer. Among them, ergothioneine was the most abundant (>65%) and most active antioxidant in P. ribis.

A mushroom-derived amino acid, ergothioneine, is a potential inhibitor of inflammation-related DNA halogenation.

Myeloperoxidase (MPO)-generated halogenating molecules, such as hypochlorous acid and hypobromous acid (HOBr), in inflammatory regions are postulated to contribute to disease progression. In this study, we showed that ergothioneine (EGT), derived from an edible mushroom, inhibited MPO activity as well as the formation of 8-bromo-2'-deoxyguanosine in vitro. The HOBr scavenging effect of EGT is higher than those of ascorbic acid and glutathione. We initially observed that the administration of Coprinus comatus, an edible mushroom containing a high amount of EGT, inhibited the UV-B-induced inflammatory responses and DNA halogenation, suggesting that EGT is a promising anti-inflammatory agent from mushrooms.

Crystallization and preliminary X-ray analysis of the ergothioneine-biosynthetic methyltransferase EgtD.

Ergothioneine is an amino-acid betaine derivative of histidine that was discovered more than one century ago. Despite significant research pointing to a function in oxidative stress defence, the exact mechanisms of action of ergothioneine remain elusive. Although both humans and bacterial pathogens such as Mycobacterium tuberculosis seem to depend on ergothioneine, humans are devoid of the corresponding biosynthetic enzymes. Therefore, its biosynthesis may emerge as potential drug target in the development of novel therapeutics against tuberculosis. The recent identification of ergothioneine-biosynthetic genes in M. smegmatis enables a more systematic study of its biology. The pathway is initiated by EgtD, a SAM-dependent methyltransferase that catalyzes a trimethylation reaction of histidine to give N(α),N(α),N(α)-trimethylhistidine. Here, the recombinant production, purification and crystallization of EgtD are reported. Crystals of native EgtD diffracted to 2.35 Å resolution at a synchrotron beamline, whereas crystals of seleno-L-methionine-labelled protein diffracted to 1.75 Å resolution and produced a significant anomalous signal to 2.77 Å resolution at the K edge. All of the crystals belonged to space group P212121, with two EgtD monomers in the asymmetric unit.

The Neurospora crassa mutant NcΔEgt-1 identifies an ergothioneine biosynthetic gene and demonstrates that ergothioneine enhances conidial survival and protects against peroxide toxicity during conidial germination.

Ergothioneine (EGT) is a histidine derivative with sulfur on the imidazole ring and a trimethylated amine; it is postulated to have an antioxidant function. Although EGT apparently is only produced by fungi and some prokaryotes, it is acquired by animals and plants from the environment, and is concentrated in animal tissues in cells with an EGT transporter. Monobromobimane derivatives of EGT allowed conclusive identification of EGT by LC/MS and the quantification of EGT in Colletotrichum graminicola and Neurospora crassa conidia and mycelia. EGT concentrations were significantly (α=0.05) higher in conidia than in mycelia, with approximately 17X and 5X more in C. graminicola and N. crassa, respectively. The first EGT biosynthetic gene in a fungus was identified by quantifying EGT in N. crassa wild type and knockouts in putative homologs of actinomycete EGT biosynthetic genes. NcΔEgt-1, a strain with a knockout in gene NCU04343, does not produce EGT, in contrast to the wild type. To determine the effects of EGT in vivo, we compared NcΔEgt-1 to the wild type. NcΔEgt-1 is not pleiotropically affected in rate of hyphal elongation in Vogel's medium either with or without ammonium nitrate and in the rate of germination of macroconidia on Vogel's medium. The superoxide-producer menadione had indistinguishable effects on conidial germination between the two strains. Cupric sulfate also had indistinguishable effects on conidial germination and on hyphal growth between the two strains. In contrast, germination of NcΔEgt-1 conidia was significantly more sensitive to tert-butyl hydroperoxide than the wild type; germination of 50% (GI(50)) of the NcΔEgt-1 conidia was prevented at 2.7 mM tert-butyl hydroperoxide whereas the GI(50) for the wild type was 4.7 mM tert-butyl hydroperoxide, or at a 1.7X greater concentration. In the presence of tert-butyl hydroperoxide and the fluorescent reactive oxygen species indicator 5-(and-6)-carboxy-2',7'-dichlorodihydrofluorescein diacetate, significantly (P=0.0002) more NcΔEgt-1 conidia fluoresced than wild type conidia, indicating that EGT quenched peroxides in vivo. While five to 21-day-old conidia of both strains germinated 100%, NcΔEgt-1 conidia had significantly (P<0.001) diminished longevity. Linear regression analysis indicates that germination of the wild type declined to 50% in 35 days, in comparison to 25 days for the NcΔEgt-1, which is equivalent to a 29% reduction in conidial life span in the NcEgt-1 deletion strain. Consequently, the data indicate that endogenous EGT helps protect conidia during the quiescent period between conidiogenesis and germination, and that EGT helps protect conidia during the germination process from the toxicity of peroxide but not from superoxide or Cu(2+). Based on an in silico analysis, we postulate that NcEgt-1 was acquired early in the mycota lineage as a fusion of two adjacent prokaryotic genes, that was then lost in the Saccharomycotina, and that NcEgt-1 catalyzes the first two steps of EGT biosynthesis from histidine to hercynine to hercynylcysteine sulfoxide.

[Studies on chemical constituents of Tylopilus plumbeoviolaceus].

OBJECTIVE: To study the chemical constituents of Tylopilus plumbeoviolaceus. METHODS: The compounds were isolated by silica gel column chromatography, and their structures were elucidated by spectral methods. RESULTS: Five compounds were isolated and identified as ergosterol (I), ergosterol 5a,8a-peroside (II), ergothioneine (III), adenosine (IV), uracil (V). CONCLUSION: All these compounds are obtained from this high fungus for the first time.

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.

Copper-thionein from fetal bovine liver.

It was of interest to examine whether or not a low molecular weight copper-rich metal-thionein was present in biological species which received no metal pretreatment at all. From bovine fetal liver an 8 Cu 2 Zn-thionein having a molecular weight of 11 500 was successfully isolated. 16% of the total copper present in the whole liver were recovered in this protein. During the isolation process anaerobic conditions had to be maintained to avoid uncontrolled oxidation leading to polymeric species and the loss of most of the copper. The similarity of both the present copper-thionein and the polymeric neonatal type mitochondrocuprein was shown. A comparison of different copper-thioneins containing variable amounts of copper was possible when xiCu from 280 nm to longer wavelength was determined. With respect to the ultraviolet properties there were no detectable differences between copper-thioneins prepared either in vivo or in vitro and the fetal copper-thionein. Furthermore, the positions of the Cotton effects as deduced from circular dichroism measurements were rather similar although the magnitude of the observed Cotton extrema was less pronounced and sometimes the signs were reversed. X-ray photoelectron spectrometric studies revealed a Cu(2p3/2) binding energy value of 932.9 eV. Unlike the S(2p1/2,3/2) value near 162 eV using Cu-thioneins from chicken liver or yeast the higher S(20p1/2,3/2) binding energy of 163.0 eV employing fetal Cu-thionein was attributed to partial oxidation of the protein moiety and/or a particular chemical environment. The second S(2p1/2,3/2) peak was assigned to the copper catalyzed oxidation of sulphur via OH to yield RSO-3. In the X-ray photoelectron spectrum of the apoprotein one homogeneous S(2p1/2,3/2) band at 163.7 eV was seen attributable to RSSR.