RESUMEN

Cultivation and extraction of the fungus Stereum hirsutum (Willd.) Pers. yielded 12 isopentenyl benzene derivatives, including six previously undescribed derivatives, named stereuins A-F. Their structures were established based on NMR and mass spectroscopy analyses, supplemented by comparison with previously reported data. Stereuins A-C are unique benzoate derivatives containing fatty acid subunits. Stereuins D and E feature a valylene group and a 6/6/6 ring system. In vitro, stereuin A significantly promoted neurite outgrowth. Several compounds exhibited antibacterial activity against Staphylococcus aureus. Stereuin F has an IC50 value of 5.2 µg/mL against S. aureus, comparable to the positive control, penicillin G sodium (1.4 µg/mL).

Asunto(s)

RESUMEN

Mushroom Jin Er has attracted widespread attention in Asia over the past two decades due to its medicinal properties and nutritional values. In the present study, Jin Er basidiocarps were often found to be surrounded by Stereum hirsutum fruiting bodies in their natural habitat and occasionally in artificial cultivation. The observation of two different kinds of mycelia within the hymenium and analyses of ITS sequences confirmed that Jin Er basidiocarps were composed of two fungal species, Naematelia aurantialba and S. hirsutum. This heterogeneity of Jin Er fruiting bodies is indeed distinct from the homogeneous hypha of Tremella fuciformis found in Yin Er mushroom, although its development also requires the presence of another fungus Annulohypoxylon stygium. Basidiospores can germinate on the surface of basidiocarps and produce mycelia. However, basidiospores in PDA medium can only bud into yeast-like conidia. The yeast-like conidia of N. aurantialba can transform into pseudohyphae with a change in temperature from 20 °C to 28 °C or switch into filamentous cells on an induction medium (IDM) at 20 °C, 25 °C and 28 °C. This dimorphic was reported for the first time in N. aurantialba. Haustorium-like structures were abundantly observed both within the hymenium and in the aerial mycelia cultured on the IDM. The developmental process was documented firstly in this study, involving the formation of protuberances with basal clamp connections, elongation at the protuberances, branch production, and eventual maturation. However, further observation is required to determine whether the haustorium-like structures can penetrate S. hirsutum hyphae. These findings are expected to provide valuable insights into the relationship and interaction between these two fungi, thereby advancing the cultivation of fruiting bodies.

RESUMEN

Wood Decay Fungi (WDF) are fungi specialized in degrading wood. An interesting perspective is their use as a source of Novel Foods or food ingredients. Here, for the first time, the metabolite profiling of hydroalcoholic and organic extracts from A. biennis, F. iberica, S. hirsutum mycelia was investigated by NMR methodology. Amino acids (alanine, arginine, asparagine, aspartate, betaine, GABA, glutamate, glutamine, histidine, isoleucine, leucine, lysine, phenylalanine, threonine, tryptophan, tyrosine, valine), sugars (galactose, glucose, maltose, trehalose, mannitol), organic acids (acetate, citrate, formate, fumarate, lactate, malate, succinate), adenosine, choline, uracil and uridine were identified and quantified in the hydroalcoholic extracts, whereas the 1H spectra of organic extracts showed the presence of saturated, mono-unsaturated and di-unsaturated fatty chains, ergosterol,1,2-diacyl-sn-glycero-3-phosphatidylethanolamine, and 1,2-diacyl-sasglycero-3-phosphatidylcholine. A. biennis extracts showed the highest amino acid concentration. Some compounds were detected only in specific species: betaine and mannitol in S. hirsutum, maltose in A. biennis, galactose in F. iberica, GABA in F. iberica and S. hirsutum, and acetate in A. biennis and S. hirsutum. S. hirsutum showed the highest saturated fatty chain concentration, whereas DUFA reached the highest concentration in A. biennis. A high amount of ergosterol was measured both in A. biennis and F. iberica. The reported results can be useful in the development of WDF-based products with a high nutritional and nutraceutical value.

RESUMEN

Three new acetylenic aromatic compounds, sterehirsutynes A-C (1-3), along with three known congeners, frustulosinol (4), vibrayne (5), and sterehirsutinol (6), were isolated from the culture broth of Stereum hirsutum. Their structures were determined by detailed analyses of NMR and high-resolution mass. Chiral column analysis showed that compounds 2 and 3 were racemic mixtures. These new compounds were evaluated for porcine pancreatic lipase (PPL) inhibitory activities, and compounds 1 and (±) 3 showed moderate inhibitory activity against PPL, with IC50 values of 23.2 ± 1.04 and 21.8 ± 2.15 µM, respectively.

Asunto(s)

RESUMEN

Eighteen linear triquinane sesquiterpenoids (LTSs), including seventeen previously undescribed ones (hirsutuminoids A-Q), were isolated from the fermentation of the fungus Stereum hirsutum (Willd.) Pers. The structures and absolute configurations of the isolates were characterized by extensive spectroscopic analysis (1D, 2D NMR, and HRMS data), together with comparing the experimental and calculated data of both electronic circular dichroism and NMR data, as well as X-ray crystallography. Based on the literature survey and efforts on constructing the absolute configurations of these LTSs in this study, one empirical rule about the orientations of substitutions at C-2/C-3/C-7/C-9 was summarized. Anti-inflammatory and cytotoxic bioassays showed that only hirsutuminoid B inhibited the nitric oxide (NO) production in RAW 264.7 macrophages with an IC50 value, 18.9 µM.

Asunto(s)

RESUMEN

In our preview research, four novel quaternary ammonium hybrids were isolated from the Stereum hirsutum FP-91666. To further discover this type of compounds, S. hirsutum was fermented in 30 L YMG broth, and eight hybrid compounds including four new quaternary ammoniums were obtained, which are sesquiterpenes combined with α-amino acids. Their structures were elucidated by extensive spectroscopic analyses, including 1D- and 2D-NMR, and HR-MS experiments.

Asunto(s)

RESUMEN

The fungal genus Stereum (Stereaceae) produces a broad variety of specialised metabolites, including a wide range of terpenes. This probably relates to the presence of an extensive biosynthetic machinery for this group of compounds: genomic analysis of Stereum hirsutum has identified 16 terpene synthase gene clusters, 6 polyketide synthase gene clusters, and 1 polyketide synthase non-ribosomal polypeptide heterodimer gene cluster in S. hirsutum FP-91666. In the present study, the One Strain Many Compounds (OSMAC) approach was employed to discover undescribed metabolites from this strain. Fermentation was carried out in five media and the products of the strain cultivated on different media were analyzed by LC-MS. From cultures grow in WGB medium (30.0 g wheat bran, 20.0 g glucose, 1.5 g KH2PO4, and 1.5 g MgSO4), four previously undescribed metabolites, a sesquiterpene sterostrein X and three mixed terpenes (stereumamides I-K) were isolated, together with seven known compounds (drimene-2,11-diol, stereumamide E, stereumamide D, stereumamide B, stereumamide A, stereumamide C, and sterostrein Q). The drimane-type sesquiterpene drimene-2,11-diol was found in S. hirsutum FP-91666 for the first time. All structures were elucidated by spectroscopic data analysis. The absolute configurations of stereumamides I, J and K were assigned by comparing their experimental and calculated electronic circular dichroism (ECD) spectra. An anti-Mycobacterium tuberculosis experiment showed that stereumamides I-K and sterostrein Q had weak antibacterial activity against this pathogen.

Asunto(s)

RESUMEN

Mushrooms are cosmopolitan organisms living on different substrates and have different pharmacological properties, such as antioxidant, antimicrobial, and anti-inflammatory effects thanks to many bioactive compounds. Edible and medicinal higher fungi have been used by humankind for millennia. They are collected and used directly not only for their nutritional values as a main source of food or as a part of a regular diet but also for their medicinal purpose as a source of powerful new bioactive compounds. Antioxidative and anti-inflammatory functions and therefore lipid-lowering effects correlate with antiatherogenic effects. This study determined the total antioxidant capacity (TAS), total oxidant capacity (TOS), oxidative stress index (OSI), 1-diphenyl-2-picrylhydrazyl (DPPH) activity, and antimicrobial activity of ethanolic and methanolic extracts of Stereum hirsutum (Willd.) Pers. Moreover, the effects on atherosclerosis are discussed according to the antioxidant activity of the mushroom. The TAS, TOS, and OSI values of S. hirsutum were determined using Rel Assay kits. According to the results, the TAS, TOS, and OSI values were determined at 5.289±0.113 mmol/L, 20.540±0.416 μmol/L, and 0.389±0.012. Furthermore, free radical scavenging activity was determined by the DPPH method. The ethanol (EtOH) extracts of S. hirsutum showed higher DPPH activity than methanol extracts. The EtOH extracts at a concentration of 2 mg/mL showed a DPPH inhibition of 45.84±0.81%. Antimicrobial activities were tested on 9 standard bacterial and fungal strains, including Staphylococcus aureus, S. aureus MRSA, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Candida albicans, C. krusei,and C. glabrata using a modified agar dilution method. Extracts showed high activity against S. aureus, S. aureus MRSA, and A.baumannii. In conclusion, it was suggested that S. hirsutum can be used as a natural source related to the effects on atherosclerosis due to its antioxidant and antimicrobial activities.

Asunto(s)

RESUMEN

Eight unexpected vibralactone homodimers, bisvibralactones A-H (1-8), and three new vibralactone monomers, hirsutumins A-C (9-11), were isolated from the culture of Stereum hirsutum. Their structures and absolute configurations were determined by detailed analyses of NMR, optical rotations, ECD, and high-resolution mass spectra as well as chemical transformation. Compounds 1-8 are unusual vibralactone dimers formed by the esterification of two vibralactone monomers. The absolute configurations of compounds 1 and 5 were determined by chemical conversions. All of the isolated compounds were evaluated for Porcine Pancreatic Lipase (PPL) inhibitory activities, and compound 10 showed significant inhibitory activity against PPL, with an IC50 value of 8.31 ± 1.04 µM.

Asunto(s)

RESUMEN

The mushroom Hericium erinaceus contains isolectins, including the ricin B-like lectin HEL1 and the core 1 O-glycan-binding lectin HEL2. Recombinant HEL2 reportedly binds O-linked glycans, but recombinant HEL1 (rHEL1) has not been characterized. HEL1 and Stereum hirsutum lectin (SHL1) orthologues, which contain the typical (QxW)3 ricin-B like motif, were evaluated. Interestingly, under non-denaturing conditions, recombinant SHL1 (rSHL1) existed as a trimer and exhibited agglutination activity, whereas rHEL1 existed as a monomer with no agglutination activity. The hemagglutination activity of rSHL1 was inhibited by N-linked glycoprotein transferrin. A glycan-array analysis revealed that the two recombinant lectins had different binding intensities toward fucosylated N-glycans harboring fucose-α(1,2) galactose or fucose-α(1,4) N-acetylglucosamine. Isothermal calorimetry showed that compared with rHEL1, rSHL1 interacted more strongly with transferrin, a fucosylated glycoprotein, than with other fucosylated disaccharide glycoconjugates. Finally, rSHL1 and rHEL1 were comparable in their ability to detect highly fucosylated N-glycans within glycoproteins on the surface of SW1116 human colorectal carcinoma cells. Therefore, these ricin B-like lectins might enable detection of highly fucosylated glycoepitopes on cancer cells for diagnostic applications.

Asunto(s)

RESUMEN

The mushroom Stereum hirsutum is parasitized by Tremella aurantia to form a heterogeneous basidiocarp Jin'er, which has been used as food and folk medicine in Chinese society. In present work, the S. hirsutum was fermented in YMG broth, and four novel mixed terpenes, stereumamides A-D (1-4), which are sesquiterpenes combined with α-amino acids to form quaternary ammonium hybrids, were isolated from the Stereum hirsutum FP-91666 and their structures were elucidated by spectroscopic data analysis. Stereumamides A and D showed antibacterial activity against Escherichia coli, Staphylococcus aureus, and Salmonella typhimurium, with the minimum inhibitory concentration (MIC) values of 12.5-25.0 µg/mL. The stereumamides A-D should be apparently the first example of naturally occurring a quaternary ammonium compound (QAC) conjugated by sesquiterpene with an α-amino acid. QAC is a common antibacterial agent in food industry, which is found in the mycelium of Stereum hirsutum would suggest that the complex basidiocarp is a functional food and veritable folk medicine.

Asunto(s)

RESUMEN

Two white rot fungi, Ceriporia sp. ZLY-2010 (CER) and Stereum hirsutum (STH) were used as biocatalysts for the biotransformation of (-)-α-pinene. After 96 hr, CER converted the bicyclic monoterpene hydrocarbon (-)-α-pinene into α-terpineol (yield, 0.05 g/L), a monocyclic monoterpene alcohol, in addition to, other minor products. Using STH, verbenone was identified as the major biotransformed product, and minor products were myrtenol, camphor, and isopinocarveol. We did not observe any inhibitory effects of substrate or transformed products on mycelial growth of the fungi. The activities of fungal manganese-dependent peroxidase and laccase were monitored for 15 days to determine the enzymatic pathways related to the biotransformation of (-)-α-pinene. We concluded that a complex of enzymes, including intra- and extracellular enzymes, were involved in terpenoid biotransformation by white rot fungi.

RESUMEN

Two new phenol derivatives, 2-(3-methyl-2-buten-1-yl)-4-methoxyethyl-phenol (1) and 5-hydroxy-4-(hydroxymethyl)-2-(3-methylbut-2-en-1-yl)cyclohex-4-en-1-one (2), together with eight known compounds consisting of phenol derivatives (3 and 4), niacinamide (5), and five ergosta type compounds (6-10), were isolated from solid fermentation products of Stereum hirsutum FP-91666. Two new structures were elucidated by extensive spectroscopic methods, including 1D NMR and 2D NMR, and HR-EI-MS experiments.

Asunto(s)

RESUMEN

Two white rot fungi, Ceriporia sp. ZLY-2010 (CER) and Stereum hirsutum (STH) were used as biocatalysts for the biotransformation of (-)-alpha-pinene. After 96 hr, CER converted the bicyclic monoterpene hydrocarbon (-)-alpha-pinene into alpha-terpineol (yield, 0.05 g/L), a monocyclic monoterpene alcohol, in addition to, other minor products. Using STH, verbenone was identified as the major biotransformed product, and minor products were myrtenol, camphor, and isopinocarveol. We did not observe any inhibitory effects of substrate or transformed products on mycelial growth of the fungi. The activities of fungal manganese-dependent peroxidase and laccase were monitored for 15 days to determine the enzymatic pathways related to the biotransformation of (-)-alpha-pinene. We concluded that a complex of enzymes, including intra- and extracellular enzymes, were involved in terpenoid biotransformation by white rot fungi.

Asunto(s)

RESUMEN

In addition to the fruiting bodies, mushroom mycelia can be used as functional foods and nutraceutical materials. In this study, two new benzoate derivatives (1 and 2) and three new sesquiterpenoids (3-5) were isolated from the mycelia of Stereum hirsutum. Their chemical structures were elucidated by NMR experiments. The absolute configuration in 3 was assigned by X-ray crystallographic analysis. In bioactivities evaluation, compounds 1 and 2 showed antimicrobial effects against methicillin-resistant Staphylococcusaureus, and S. aureus with the MIC values of 25.0µg/mL; compounds 1 and 3 inhibited the NO overproduction in the LPS-induced macrophages with the IC50 values of 19.17 and 15.44µM, and also displayed cytotoxicity against A549 and HepG2 with IC50 in the range of 10-50µM. These results support the usage of the mycelia of S. hirsutum as a good functional food.

Asunto(s)