Fungal Depsidones Stimulate AKT-Dependent Glucose Uptake in 3T3-L1 Adipocytes.

Enhanced glucose uptake in insulin-sensitive tissues is one of the therapeutic strategies to ameliorate hyperglycemia and maintain glucose homeostasis in type 2 diabetes. This study disclosed the role of fungal depsidones in glucose uptake and the underlying mechanism in 3T3-L1 adipocytes. Depsidones, including nidulin, nornidulin, and unguinol, isolated from Aspergillus unguis, stimulate glucose uptake in adipocytes. Compared to the others, nidulin exhibited an upward trend in glucose uptake. The effect of nidulin was found to be dose- and time-dependent. Nidulin also enhanced insulin- and metformin-stimulated glucose uptake. Upregulation of GLUT4 expression and AKT and AMPK phosphorylation were observed with nidulin treatment. Blockage of AKT, but not AMPK, phosphorylation was largely accompanied by diminished glucose uptake. In agreement, nidulin triggered the translocation of GLUT4 to the plasma membrane. Importantly, nidulin elevated glucose uptake associated with increased AKT phosphorylation in insulin-resistant adipocytes. Taken together, nidulin could stimulate glucose uptake mainly through AKT-dependent GLUT4 translocation, serving as a seed compound in drug discovery for type 2 diabetes.

Oudemansin and 9-methoxystrobilurin derivatives with antimalarial activity from cultures of the basidiomycete Favolaschia minutissima: assignments of the absolute configurations of the isoprene-derived units.

Five undescribed polyketide metabolites, oudemansins E (1), M (2), P (3), and Q (4), and 9-methoxystrobilurin I (5), were isolated from cultures of basidiomycete Favolaschia minutissima TBRC-BCC 19434. A γ-lactone derivative (6) of noroudemansin A (8), which was previously reported as a semisynthetic compound, was also isolated. The absolute configuration of the isoprene-derived moiety of the known cometabolite 9-methoxystrobilurin E (9) was determined to be 2'R,6'S by comparison of the experimental and calculated ECD data, which was correlated to the new derivative 1. These compounds exhibited antimalarial activity against Plasmodium falciparum K1 (multidrug-resistant strain). A putative minor natural product, namely 9-methoxystrobilurin P (13), was prepared by semisynthesis, which exhibited significant antimalarial activity (IC50 0.086 µM).

Antimalarial Lanostane Dimers from Artificially Cultivated Fruiting Bodies of Ganoderma weberianum.

Investigation of cultivated fruiting bodies of Ganoderma weberianum led to the isolation of 11 previously unreported lanostane dimers, ganoweberianones C (3a), D (4a), E (5a), F (6a), G (7a), and H (8a) and isoganoweberianones A (1b), B (2b), D (4b), G (7b), and H (8b). Six new ganodermanontriol derivatives as three pairs of diastereomers (11/12, 13/14, and 15/16) and five new ganoweberianic acids (17-21) were also isolated. A method for semisynthesis of lanostane dimers by condensation of natural lanostanes was established, which was utilized in the structure elucidation and NMR data assignments of the undescribed natural lanostane dimers. Ganoweberianone D (4a) and isoganoweberianone D (4b) showed significant antimalarial activity against Plasmodium falciparum K1 (multidrug-resistant strain) with IC50 values of 0.057 and 0.035 µM, respectively, whereas their cytotoxicity to Vero cells was weaker (IC50 8.1 and 19 µM, respectively).

Antroxazole A, an oxazole-containing chamigrane dimer from the fungus Antrodiella albocinnamomea with immunosuppressive activity.

Antroxazole A (1), a chamigrane type sesquiterpene dimer containing an oxazole moiety, has been characterized from cultures of the fungus Antrodiella albocinnamomea. The structure with absolute configuration was determined by extensive spectroscopic methods and single crystal X-ray diffraction. A plausible biosynthetic pathway for 1 was proposed. Compound 1 exhibits inhibition specifically against the LPS-induced proliferation of B lymphocyte cells with an IC50 value of 16.3 µM.

Ganoweberianones A and B, Antimalarial Lanostane Dimers from Cultivated Fruiting Bodies of the Basidiomycete Ganoderma weberianum.

Two lanostane dimers, ganoweberianones A (1) and B (2), together with seven previously undescribed lanostanes, ganoweberianic acids A-G (3-9), and three known compounds (10-12), were isolated from the artificially cultivated fruiting bodies of the basidiomycete Ganoderma weberianum. Ganoweberianone A (1) exhibited significant antimalarial activity against Plasmodium falciparum K1 (multidrug-resistant strain) with an IC50 value of 0.050 µM. A method for semisynthesis of 1 by condensation of the corresponding lanostane monomers and acid-catalyzed intramolecular transesterification was demonstrated.

Highly Modified Lanostane Triterpenes from the Wood-Rot Basidiomycete Ganoderma colossus: Comparative Chemical Investigations of Natural and Artificially Cultivated Fruiting Bodies and Mycelial Cultures.

The wood-rot basidiomycete Ganoderma colossus has been chemically investigated. Comparative analyses of the natural fruiting body, artificially cultivated fruiting bodies, and mycelial cultures resulted in the isolation, in total, of 13 new highly modified lanostanes, ganocolossusins A-H (1-8) and ganodermalactones T-X (9-13), together with 23 known compounds (14-36). There were significant overlaps of the same compounds among the three different states of the fungal materials. Ganocolossusin D (4) displayed the most potent antimalarial activity against Plasmodium falciparum K1 (multi-drug-resistant strain) with an IC50 value of 2.4 µM, while it was noncytotoxic to Vero cells at 50 µg/mL.

Antimalarial 9-Methoxystrobilurins, Oudemansins, and Related Polyketides from Cultures of Basidiomycete Favolaschia Species.

Fourteen new compounds, oudemansins 1-4, oudemansinols 5-7, favolasins 8-10, favolasinin (12), polyketides 13-15, and (R,E)-2,4-dimethyl-5-phenyl-4-pentene-2,3-diol (16), together with nine known compounds were isolated from the basidiomycete fungus Favolaschia sp. BCC 18686. Two new compounds, favolasin E (11) and 9-oxostrobilurin E (17), were isolated from the closely related organism Favolaschia calocera BCC 36684 along with nine ß-methoxyacrylate-type derivatives. Compounds in the class of oudemansins and strobilurins exhibited moderate to strong antimalarial activity with relatively low cytotoxicity against Vero cells (African green monkey kidney fibroblasts). Potent antimalarial activity was demonstrated for 9-methoxystrobilurins G, K, and E (IC50 values 0.061, 0.089, and 0.14 µM, respectively). The structure-activity relationships (SAR) for antimalarial activity is proposed on the basis of the activity of the new and several known ß-methoxyacrylate derivatives in combination with the data from previously isolated compounds. Furthermore, several compounds showed specific cytotoxicity against NCI-187 cells (human small-cell lung cancer), although the SAR was different from that for antimalarial activity.

Highly Modified Lanostane Triterpenes from Fruiting Bodies of the Basidiomycete Tomophagus sp.

Thirty-one highly modified lanostanes (1-31), together with 19 known compounds (32-50), were isolated from fruiting bodies of the wood-rot basidiomycete Tomophagus sp. The structures were elucidated by analyses of HRMS and NMR spectroscopic data. The present work demonstrates the high structural diversity of modified lanostane triterpenoids from Tomophagus. This paper also discusses structural revisions of several known derivatives. Some of the isolated compounds exhibited moderate antimalarial activity against Plasmodium falciparum K1 (IC50 5.1-19 µM).

Structural Determination of (-)-SCH 64874 and Hirsutellomycin by Semisynthesis.

The structure of a C2-symmetric epidithiodiketopiperazine alkaloid, SCH 64874, was determined by semisynthesis. The relative stereochemistry of the ß-hydroxy carboxylic acid chain having three chiral centers was determined by comparison of the NMR data of the four possible diastereomeric ß-hydroxy carboxylic acid fragments with those of SCH 64874. Condensation of the (-)-deacetylaranotin core with two enantiomeric ß-hydroxy carboxylic acids revealed the relative stereochemistry of SCH 64874. The relative stereochemistry of the ß-keto carboxylic acid chain of the analogous alkaloid hirsutellomycin was determined in a stepwise manner. The C4'-C6' syn relationships were predicted by comparing the NMR data of the corresponding ester fragments with that of hirsutellomycin. The relative stereochemistry of the whole molecule, including the epimerizable C2' stereocenter, was determined by introduction of four possible side chains into the bisdethiodi(methylthio)deacetylaranotin core. We found that the stereochemistry of C2' converged with that of the thermodynamically stable form influenced by the core structure.

Antitubercular Activity of Mycelium-Associated Ganoderma Lanostanoids.

In a continuation of our research into antitubercular lanostane triterpenoids from submerged cultures of Ganoderma species, three strains, Ganoderma orbiforme BCC 22325, Ganoderma sp. BCC 60695, and Ganoderma australe BCC 22314, have been investigated. Fourteen new lanostane triterpenoids, together with 35 known compounds, were isolated. Antitubercular activities of these mycelium-associated Ganoderma lanostanoids against Mycobacterium tuberculosis H37Ra were evaluated. Taken together with the assay data of previously isolated compounds, structure-activity relationships of the antitubercular activity are proposed. Most importantly, 3ß- and 15α-acetoxy groups were shown to be critical for antimycobacterial activity. The most potent compound was (24E)-3ß,15α-diacetoxylanosta-7,9(11),24-trien-26-oic acid (35).

Antitubercular Lanostane Triterpenes from Cultures of the Basidiomycete Ganoderma sp. BCC 16642.

Sixteen new lanostane triterpenoids (1-16), together with 26 known compounds (17-42), were isolated from cultures of the basidiomycete Ganoderma sp. BCC 16642. Antitubercular activities of these Ganoderma lanostanoids against Mycobacterium tuberculosis H37Ra were evaluated, and structure-activity relationships are proposed.

Antimalarial 9-methoxystrobilurin derivatives from cultures of the basidiomycete Favolaschia minutissima.

Investigation of cultures of the basidiomycete Favolaschia minutissima TBRC-BCC 19434 led to the isolation of two undescribed ß-methoxyacrylate metabolites, 9-methoxystrobilurins R (1) and S (2), and a degraded aldehyde derivative, favodehyde E (3). 9-Methoxystrobilurin derivatives 1 and 2 exhibited significant antimalarial activity against Plasmodium falciparum K1 (multidrug-resistant strain) with IC50 values of 0.12 and 0.21 µM, respectively.

Ganopyrone A, a highly rearranged lanostane triterpenoid with antimalarial activity from artificially cultivated fruiting bodies of Ganoderma colossus.

Three previously undescribed highly modified lanostane triterpenoids, ganopyrone A, ganocolossusin I, and ganodermalactone Y, were isolated from the artificially cultivated fruiting bodies of the basidiomycete Ganoderma colossus TBRC-BCC 17711. Ganopyrone A possesses an unprecedented polycyclic carbon skeleton with an α-pyrone ring and C-18/C-23 bond. It showed antimalarial activity against Plasmodium falciparum K1 (multidrug-resistant strain) with an IC50 value of 7.8 µM (positive control: dihydroartemisinin, IC50 1.4 nM), while its cytotoxicity (Vero cells) was much weaker (IC50 103 µM).

Chemical analysis and antitubercular activity evaluation of the dried mycelial powders of the basidiomycete Ganoderma australe TBRC-BCC 22314.

The isolation of lanostane triterpenoids possessing significant anti-tuberculosis (anti-TB) activity from mycelial cultures of the basidiomycete Ganoderma australe strain TBRC-BCC 22314 was previously reported. To demonstrate the potential of the dried mycelial powder for utilization in anti-TB medicinal products, its authentic chemical analysis was performed. Considering the possibility of the changes in the lanostane compositions and anti-TB activity by sterilization, both autoclave treated and non-autoclaved mycelial powder materials were chemically investigated. The study led to the identification of the lanostanes responsible for the activity of the mycelial extract against Mycobacterium tuberculosis H37Ra. The anti-TB activity of the extracts from autoclaved and non-autoclaved mycelial powders were the same (MIC 3.13 µg/mL). However, the analytical results revealed several unique chemical conversions of the lanostanes under the sterilization conditions. The most potent major lanostane, ganodermic acid S (1), was shown to be significantly active also against the extensively drug-resistant (XDR) strains of M. tuberculosis.

Colossolactone J, a highly modified lanostane triterpenoid from a natural fruiting body of Ganoderma colossus.

Colossolactone J (1), an undescribed lanostane triterpenoid was isolated from a natural fruiting body of Ganoderma colossus using silica gel column chromatography and preparative HPLC. Its structure was elucidated on the basis of the spectroscopic method. The absolute configuration was determined by the combination of the modified Mosher's method and detailed NMR data analysis.

Lanostane triterpenoids from artificially cultivated fruiting bodies of Ganoderma cf. mastoporum.

In the quest for bioactive compounds from Ganoderma, artificially cultivated fruiting bodies of Ganoderma cf. mastoporum, strain TBRC-BCC 47851 were chemically investigated. The study led to the isolation of three undescribed lanostane triterpenoids (1-3) together with twelve known compounds. The structures were elucidated on the basis of NMR spectroscopic and mass spectrometry data. The new compounds were inactive in the antimalarial and antitubercular activity assays.

Pyridylnidulin exerts anti-diabetic properties and improves non-alcoholic fatty liver disease in diet-induced obesity mice.

Introduction: Non-alcoholic fatty liver disease (NAFLD) is one of the metabolic disorders related to the pathophysiology of type 2 diabetes mellitus (T2DM). Therapeutic strategies are focused on the improvement of energy balance and lifestyle modification. Additionally, the derivative of the bioactive fungal metabolite is of interest to provide health benefits, especially in obese and pre-diabetic conditions. In our screening of anti-diabetic compounds from fungal metabolites and semisynthetic derivatives, a depsidone derivative, namely pyridylnidulin (PN), showed potent glucose uptake-inducing activity. The present study aimed to investigate the liver lipid metabolism and anti-diabetic properties of PN in diet-induced obesity mice. Methods: Male C57BL/6 mice were induced obesity and pre-diabetic conditions by dietary intervention with a high-fat diet (HFD) for 6 weeks. These obese mice were orally administered with PN (40 or 120 mg/kg), metformin (150 mg/kg), or vehicle for 4 weeks. Glucose tolerance, plasma adipocytokines, hepatic gene and protein expressions were assessed after treatment. Results: Improved glucose tolerance and reduced fasting blood glucose levels were found in the PN and metformin-treated mice. Additionally, hepatic triglyceride levels were consistent with the histopathological steatosis score regarding hepatocellular hypertrophy in the PN and metformin groups. The levels of plasma adipocytokines such as tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1) were reduced in the PN (120 mg/kg) and metformin-treated mice. In addition, hepatic gene expression involved in lipid metabolism, including lipogenic enzymes was significantly reduced in the PN (120 mg/kg) and metformin-treated mice. The increased protein expression levels of phosphorylated AMP-activated protein kinase (p-AMPK) was also found in PN and metformin-treated mice. Discussion: Considering the increased p-AMPK protein expression levels in PN and metformin-treated mice were revealed as the underlying mechanisms to improve metabolic parameters. These results suggested that PN provided the health benefit to slow the progression of NAFLD and T2DM in obese and pre-diabetic conditions.

[20(22)E]-Lanostane Triterpenes from the Fungus Ganoderma australe.

Twelve new lanostane triterpenoids (1-5, 7-13) were isolated from the fruiting bodies of the fungus Ganoderma australe. The structures of the new compounds were elucidated by extensive 1D and 2D NMR, and HRESIMS spectroscopic analysis. All the triterpenes are featured by 20(22)E configurations which are uncommon in the Ganoderma triterpene family. The absolute configuration of the C-25 of compounds 1, 2, and 6 were determined by the phenylglycine methyl ester (PGME) method. A postulated biosynthetic pathway for compound 1 was discussed. This study opens new insights into the secondary metabolites of the chemically underinvestigated fungus G. australe.

Lanostane triterpenoids from cultivated fruiting bodies of basidiomycete Ganoderma mbrekobenum.

In the quest for medicinally active compounds in mushrooms of the genus Ganoderma, eleven undescribed lanostane triterpenoids, including a novel chlorinated derivative, i.e., (20S,24E)-21-chloro-15ß,20,29-trihydroxy-3,7,11-trioxolanosta-8,24-dien-26-oic acid, were isolated from artificially cultivated fruiting bodies of the basidiomycete Ganoderma mbrekobenum. The structures were elucidated on the basis of NMR spectroscopic and mass spectrometry data. The configuration of the C-20 atom in the most abundant 20-hydroxy-lanostane, (20S,24E)-15ß,20,29-trihydroxy-3,7,11-trioxolanosta-8,24-dien-26-oic acid, was established by chemical derivatization, and the absolute configuration of the lanostane skeleton was determined by ECD calculation. Two of the undescribed compounds exhibited moderate antimalarial activity.

Ring B aromatic norpimarane glucoside from a Xylaria sp.

A novel 20-norpimarane glucoside, xylopimarane (1), together with the known sphaeropsidin C (2) and clonostachydiol (3), was isolated from the fungus Xylaria sp. BCC 4297. Compound 1 exhibited cytotoxicity to cancer cell lines KB, MCF-7, and NCI-H187 with respective IC(50) values of 1.0, 13, and 65 µM.