Ergosterol Derivatives Research Articles

New and antioxicant secondary metabolites from the endophytic fungus Nigrospora sphaerica

A new isochromene derivative (1), was isolated from the endophytic fungus Nigrospora sphaerica and chemically identified as 3-(3,4-dihydroxyphenyl)-4,6,8-trihydroxy-1 H-isochromen-1- one-6-O-b-D-glucopyranoside. In addition nineteen known compounds (2 – 20) have been isolated and were chemically identified to be seven ergosterol derivatives (2 – 8), 4-(hydroxymethyl)-3,5- dimethyl dihydrofuran-2(3 H)-one (9), 3-(1-hydroxyethyl)-4-methyl dihydrofuran-2(3 H)-one (10), uridine (11), adenosine (12), 3-benzylhexahydropyrrolo[1,2-a]pyrazine-1,4-dione (13), 3-methylhexahydro pyrrolo [1,2-a]pyrazine-1,4-dione (14), methyl 4-hydroxybenzoate (15), 4-(2-hydro-xyethyl)phenol (16) and four fatty acids (17 – 20). In vitro antioxidant activities of (1 – 20) were examined. The antioxidant activity was expressed in terms of CAA units. Compounds 1, 13 and 14 showed activities as shown in the table:

A new benzyl ester and ergosterol derivatives from the fungus Gymnoascus reessii

A new benzyl ester, reessiate (1), anthraquinone, islandicin (2), ergosterol and seven ergosterol derivatives (3–9) were isolated from the fungus Gymnoascus reessii. All structures were identified by spectroscopic methods. This is the first report of their isolation from this fungus. Compounds 4–7 and 9 exhibited antimalarial activity against Plasmodium falciparum with IC50 values in the range of 3.3–4.5 μg/mL. In addition, 4 showed cytotoxicity against KB, MCF7 and NCI-H187 cancer cell lines. It was found that 4 has cytotoxic effect to MCF7 (IC50 = 7.9 μg/mL) lower than Doxorubicin (IC50 = 8.5 μg/mL).

Lipid Constituents of the Edible Mushroom, Pleurotus giganteus Demonstrate Anti-Candida Activity

Different solvent extracts of Pleurotus giganteus fruiting bodies were tested for antifungal activities against Candida species responsible for human infections. The lipids extracted from the ethyl acetate fraction significantly inhibited the growth of all the Candida species tested. Analysis by GC/MS revealed lipid components such as fatty acids, fatty acid methyl esters, ergosterol, and ergosterol derivatives. The sample with high amounts of fatty acid methyl esters was the most effective antifungal agent. The samples were not cytotoxic to a mammalian cell line, mouse embryonic fibroblasts BALB/c 3T3 clone A31. To our knowledge, this is the first report of antifungal activity of the lipid components of Pleurotus giganteus against Candida species.

Storage temperature and UV-irradiation influence on the ergosterol content in edible mushrooms

Ergosterol (5,7,22-ergostatrien-3β-ol) and ergosteryl derivatives from different genera of edible mushrooms were separated and quantified by an isocratic reversed-phase high performance liquid chromatography (HPLC) method. The technique allowed a rapid separation of free ergosterol and two ergosteryl derivatives occurring in mushrooms. The ergosterol content varied considerably depending on the fungus. Thus, the species Agaricus bisporus and Hygrophorus marzuolus presented high quantities of ergosterol (6.4–6.8mg/g, dry matter) followed by Pleurotus ostreatus, Calocybe gambosa, Lentinus edodes, and Boletus edulis (3.3–4.0mg/g). In contrast, other species, such as Cantharellus cibarius, Lactarius deliciosus and Craterellus cornucopioides, contained significantly lower ergosterol amounts (0.2–0.4mg/g). Two ergosteryl derivatives were found in mushrooms and also the content depended on the fungus. The stability of ergosterol, in terms of the formation of ergosterol peroxide, was evaluated under different storage temperatures and UV radiation. The lower the temperature (−20°C) and the radiation time (10min), the lower ergosterol oxidation was observed.

Synthesis of Ergosterol and 5,6-Dihydroergosterol Glycosides and Their Inhibitory Activities on Lipopolysaccharide-Induced Nitric Oxide Production

We have synthesized several glycosyl ergosterols and 5,6-dihydroergosterols (DHE) and examined their effects on production of nitric oxide (NO) and iNOS protein expression in LPS-treated RAW264.7 macrophage cells. Our results showed that DHE derivatives inhibited production of NO and iNOS protein expression more strongly than ergosterol derivative. Especially, DHE-Glc exhibited most potent inhibitory activity without cytotoxicity up to the concentration of .

Inhibition of human neutrophil elastase by ergosterol derivatives from the mycelium of Phellinus linteus

Inhibition of human neutrophil elastase by ergosterol derivatives from the mycelium of Phellinus linteus

Structural complex of sterol 14α-demethylase (CYP51) with 14α-methylenecyclopropyl-Δ7-24, 25-dihydrolanosterol

Sterol 14α-demethylase (CYP51) that catalyzes the removal of the 14α-methyl group from the sterol nucleus is an essential enzyme in sterol biosynthesis, a primary target for clinical and agricultural antifungal azoles and an emerging target for antitrypanosomal chemotherapy. Here, we present the crystal structure of Trypanosoma (T) brucei CYP51 in complex with the substrate analog 14α-methylenecyclopropyl-Δ7-24,25-dihydrolanosterol (MCP). This sterol binds tightly to all protozoan CYP51s and acts as a competitive inhibitor of F105-containing (plant-like) T. brucei and Leishmania (L) infantum orthologs, but it has a much stronger, mechanism-based inhibitory effect on I105-containing (animal/fungi-like) T. cruzi CYP51. Depicting substrate orientation in the conserved CYP51 binding cavity, the complex specifies the roles of the contact amino acid residues and sheds new light on CYP51 substrate specificity. It also provides an explanation for the effect of MCP on T. cruzi CYP51. Comparison with the ligand-free and azole-bound structures supports the notion of structural rigidity as the characteristic feature of the CYP51 substrate binding cavity, confirming the enzyme as an excellent candidate for structure-directed design of new drugs, including mechanism-based substrate analog inhibitors.

1,4-Dioxane and ergosterol derivatives from Withania somnifera roots

The chemical investigation on the n-hexane extract of Withania somnifera roots has yielded octacosane, oleic and stearic fatty acids, stigmasterone, stigmasterol, sitostanone, oleanolic acid along with the ergosterol and 1,4-dioxane derivatives as new compounds. The isolation of alkenyl-1,4-dioxane compound is rare, whereas the ergosterol derivative may have biogenetic significance in the lactone formation in the E ring of withanolides. The presence of a 1,4-dioxane derivative in the nonpolar extract of roots assumes importance as this type of compound has not been reported earlier from W. somnifera. The structures of new compounds were elucidated by spectroscopic methods and chemical transformations.

Antioxidant and Cytotoxic Activity of the Wild Edible Mushroom Gomphus clavatus

The fruiting bodies of the edible mushroom Gomphus clavatus (Family Gomphaceae) were collected from the wild and extracted with solvents of increasing polarity. Crude extracts were evaluated for their total phenolic content, their antioxidant capacity, and their cytotoxic activity against MCF-7 and PC-3 cancer cell lines. Concerning total phenolics and antioxidant activity, the methanol extract showed the most potent radical scavenging activity with inhibition of 45.5% of 1,1-diphenyl-2-picrylhydrazyl at 3 mg/mL. Further chemical investigation of the methanol extract led to the isolation and identification of nine compounds, among them four ergosterol derivatives. Concerning cytotoxicity, the dichloromethane (DCM) extract showed the most interesting activity, with half-maximal inhibitory concentration (IC(50)) values of 55.3 and 49.0 μg/mL in the MCF-7 and PC-3 cell lines, respectively. Further investigation of the DCM extract lead to the identification of methyl esters of fatty acids and the isolation of four fatty acids and three ergosterol derivatives. Ergosterol peroxide (compound 6) was one of the most active constituents, with IC(50) values of 35.8 μM and 30.6 μM for MCF-7 and PC-3 cells, respectively, suggesting that the cytotoxic activity of the crude extract could be at least partly attributed to the presence of ergostan derivatives. Those findings suggest that G. clavatus can be considered as a medicinal food with antioxidant and chemopreventive activities.

Ganodermasides A and B, two novel anti-aging ergosterols from spores of a medicinal mushroom Ganoderma lucidum on yeast via UTH1 gene

Two novel ergosterol derivatives, ganodermasides A and B, hydroxylated at C-15 were isolated from the methanol extract of spores of a medicinal mushroom, Ganoderma lucidum, showed to extend the replicative life span of Saccharomyces cerevisiae, a yeast of K6001 strain. The stereostructures of ganodermasides A and B were determined based on the spectroscopic analysis and comparison of spectroscopic data. These new sterols have a 4, 6, 8(14), 22-tetraene-3-one unit with a unique hydroxylation at C-15. The anti-aging activity of these compounds on yeast is comparable to a well-known substance, resveratrol. Based on results of the investigation of the mechanism of biological activity, ganodermasides A and B regulated UTH1 expression in order to extend the replicative life span of yeast.

Pro-apoptotic activity of ergosterol derivatives in human prostate cancer cells

Pro-apoptotic activity of ergosterol derivatives in human prostate cancer cells

Bioactive ergosterol derivatives isolated from the fungus Lactarius hatsudake

Bioactive ergosterol derivatives isolated from the fungus Lactarius hatsudake

Ergosterol peroxides as phospholipase A2 inhibitors from the fungus Lactarius hatsudake

Four ergosterol derivatives (1-4) have been isolated for the first time from the fruiting bodies of a basidiomycete fungus, Lactarius hatsudake, through activity-guided fractionation. Their structures were determined, using spectroscopic analysis, as: (22E,24R)-ergosta-5,7,22-dien-3beta-ol (ergosterol, 1); 5alpha,8alpha-epidioxy-(22E,24R)-ergosta-6,22-dien-3beta-ol (ergosterol peroxide, 2); 5alpha,8alpha-epidioxy-(24S)-ergosta-6-en-3beta-ol (3); and (22E,24R)-ergosta-7,22-dien-3beta,5alpha,6beta-triol (cerevisterol, 4). Compounds 2 and 3 showed selective inhibitory activity against Crotalus adamenteus venom phospholipase A(2) (PLA(2)) enzyme, but not against Apis mellifcra bee venom PLA(2). The antiphospholipase A(2) activity of compounds 2 and 3 are reported here for the first time.

Cytotoxic ergosterols from Paecilomyces sp. J300.

Seven ergosterol derivatives (1-7) were isolated from silkworm larvae infected with Paecilomyces sp. J300. On the basis of spectroscopic means, their structures have been elucidated as 3beta,5alpha-dihydroxy-ergosta-7,22-diene (1), 5alpha,6alpha-epoxy-(22E,24R)-ergosta-8(14), 22-diene-3beta, 7alpha-diol (2), 5alpha,6alpha-epoxy-(22E,24R)-ergosta-8,22-diene-3beta,7alpha-diol (3), ergosta-4,6,8(14),22-tetraene-3-one (4), ergosterol (5), ergosterol endoperoxide (6), 3beta,5alpha-dihydroxy-6beta-methoxyergosta-7,22-diene (7). Compounds 3-7 showed moderate cytotoxicity against five tumor cells.

A novel sterol from Chinese truffles Tuber indicum.

From the fruiting bodies of Ascomycetes Tuber indicum, a new steroidal glucoside with polyhydroxy ergosterol nucleus, tuberoside (2), has been isolated along with additional four known ergosterol derivatives, (22E, 24R)-ergosta-7, 22-dien-3beta, 5alpha, 6beta-triol (1), 5alpha, 8alpha-epidioxy-(22E, 24R)-ergosta-6, 22-dien-3beta-ol (3), (22E, 24R)-ergosta-5, 22-dien-3beta-ol (4), and (22E, 24R)-ergosta-4, 6, 8(14), 22-tetraen-3-one (5). The structure of new compound was established as 3-O-beta-D-glucopyranosyl-(22E, 24R)-ergosta-7, 22-dien-5alpha, 6beta-diol (2) on the basis of chemical and spectroscopic means ((1)H NMR, (13)C NMR, HMQC, HMBC, MS, and IR). This is the first example of isolation of a polyhydroxylated ergosterol glucoside from higher fungi in nature.

Effects of singlet oxygen on membrane sterols in the yeast Saccharomyces cerevisiae.

Photodynamic treatment of the yeast Saccharomyces cerevisiae with the singlet oxygen sensitizer toluidine blue and visible light leads to rapid oxidation of ergosterol and accumulation of oxidized ergosterol derivatives in the plasma membrane. The predominant oxidation product accumulated was identified as 5alpha, 6alpha-epoxy-(22E)-ergosta-8,22-dien-3beta,7a lpha-diol (8-DED). 9(11)-dehydroergosterol (DHE) was identified as a minor oxidation product. In heat inactivated cells ergosterol is photooxidized to ergosterol epidioxide (EEP) and DHE. Disrupted cell preparations of S. cerevisiae convert EEP to 8-DED, and this activity is abolished in a boiled control indicating the presence of a membrane associated enzyme with an EEP isomerase activity. Yeast selectively mobilizes ergosterol from the intracellular sterol ester pool to replenish the level of free ergosterol in the plasma membrane during singlet oxygen oxidation. The following reaction pathway is proposed: singlet oxygen-mediated oxidation of ergosterol leads to mainly the formation of EEP, which is enzymatically rearranged to 8-DED. Ergosterol 7-hydroperoxide, a known minor product of the reaction of singlet oxygen with ergosterol, is formed at a much lower rate and decomposes to give DHE. Changes of physical properties of the plasma membrane are induced by depletion of ergosterol and accumulation of polar derivatives. Subsequent permeation of photosensitizer through the plasma membrane into the cell leads to events including impairment of mitochondrial function and cell inactivation.

Evaluation of a Fluorodensitometric Method for Analysis of Ergosterol as a Fungal Marker in Compound Feeds

Ergosterol is the principal sterol of fungi and plays an essential role as a component of the cell membrane and other cell constituents. This molecule is considered a good marker of fungal contamination in foods and feeds. This paper reports a rapid and sensitive method to test ergosterol content in compound feeds based on fluorodensitometry after thin-layer chromatography (TLC) separation. This method involves a thermal treatment of TLC plates that leads to the formation of a highly fluorescent ergosterol derivative. Such a dosage allows ergosterol testing in any naturally contaminated samples (limit of detection: 1 ppm of ergosterol) and gives results in close agreement with high-pressure liquid chromatography determination. Moreover, values obtained on mixed feeds for animals at different steps of fungal contamination are linked to quantitative development of storage fungi, evaluated by mycological technique, reinforcing the interest of a rapid method for measuring this fungal marker.

4-hydroxy-17-methylincisterol, an inhibitor of DNA polymerase-α activity and the growth of human cancer cells in vitro

An ergosterol derivative, 4-hydroxy-17-methylincisterol (HMI), was found to be an inhibitor of mammalian DNA polymerases in vitro. HMI inhibited the activity of calf thymus DNA polymerase α (pol. α). Among the polymerases tested, pol. α was the most sensitive to inhibition by HMI, and the inhibition was concentration dependent. The inhibitory effect of HMI on pol. α was almost the same as that shown by aphidicolin, a well-known potent pol. α inhibitor. HMI had relatively less effect on rat DNA pol. β, human immunodeficiency virus type 1 reverse transcriptase (HIV-RT), and calf thymus terminal deoxynucleotidyl transferase (TdT) in vitro, and did not influence the activities of prokaryotic DNA polymerases such as Klenow Fragment of DNA polymerase I, or the DNA-metabolic enzyme DNase I. HMI was found to be able to prevent the growth of human cancer cell lines originating from patients with leukemia or various solid tumors; its ic 50 values ranged from 7.5 to 12 μM. We also synthesized other ergosterol derivatives and tested them, and found that two compounds, 17-methylincisterol and 4-acetyl-17-methylincisterol, have similar inhibitory effects.

Transcriptional regulation by ergosterol in the yeast Saccharomyces cerevisiae.

Sterol biosynthesis in the yeast Saccharomyces cerevisiae is an energy-expensive, aerobic process, requiring heme and molecular oxygen. Heme, also synthesized exclusively during aerobic growth, not only acts as an enzymatic cofactor but also is directly and indirectly responsible for the transcriptional control of several yeast genes. Because of their biosynthetic similarities, we hypothesized that ergosterol, like heme, may have a regulatory function. Sterols are known to play a structural role in membrane integrity, but regulatory roles have not been characterized. To test possible regulatory roles of sterol, the promoter for the ERG3 gene, encoding the sterol C-5 desaturase, was fused to the bacterial lacZ reporter gene. This construct was placed in strains making aberrant sterols, and the effect of altered sterol composition on gene expression was monitored by beta-galactosidase activity. The absence of ergosterol resulted in a 35-fold increase in the expression of ERG3 as measured by beta-galactosidase activity. The level of ERG3 mRNA was increased as much as ninefold in erg mutant strains or wild-type strains inhibited in ergosterol biosynthesis by antifungal agents. The observed regulatory effects of ergosterol on ERG3 are specific for ergosterol, as several ergosterol derivatives failed to elicit the same controlling effect. These results demonstrate for the first time that ergosterol exerts a regulatory effect on gene transcription in S. cerevisiae.

Adaptation of Aspergillus niger to Multiple Agents Whose Action Mechanisms are Different.

Adaptation of Aspergillus niger to amphotericin B (AMPH) and two imidazoles (miconazole (MCZ) and ketoconazole (KCZ)) was observed at a single hypha level with a continuous measurement system. It was found that a test hypha adapted to MCZ or KCZ was also adapted to AMPH but that a hypha adapted to AMPH was not adapted either to MCZ or KCZ. These adaptation phenomena to respective agents did not occur after incubation in the medium supplemented with ergosterol. The cross adaptation phenomena were suspected to be due to modification of the synthesis pathway of ergosterol and related derivatives.