Pogostol Biosynthesis by the Endophytic FungusGeniculosporium

Secondary Metabolites of Biscogniauxia: Distribution, Chemical Diversity, Bioactivity, and Implications of the Occurrence

The genus Biscogniauxia, a member of the family Xylariaceae, is distributed worldwide with more than 50 recognized taxa. Biscogniauxia species is known as a plant pathogen, typically acting as a parasite on tree bark, although certain members of this genus also function as endophytic microorganisms. Biscogniauxia endophytic strain has received attention in many cases, which includes constituent research leading to the discovery of various bioactive secondary metabolites. Currently, there are a total of 115 chemical compounds belonging to the class of secondary metabolites, and among these compounds, fatty acids have been identified. In addition, the strong pharmacological agents of this genus are (3aS,4aR,8aS,9aR)-3a-hydroxy-8a-methyl-3,5-dimethylenedecahydronaphto [2,3-b]furan-2(3H)-one (HDFO) (antifungal), biscopyran (phytotoxic activity), reticulol (antioxidant), biscogniazaphilone A and B (antimycobacterial), and biscogniauxone (Enzyme GSK3 inhibitor). This comprehensive research contributes significantly to the potential discovery of novel drugs produced by Biscogniauxia and holds promise for future development. Importantly, it represents the first-ever review of natural products originating from the Biscogniauxia genus.

Anti-inflammatory and anti-proliferative activities of chemical constituents from fungus Biscogniauxia whalleyi SWUF13-085

The fungus Biscogniauxia whalleyi SWUF13-085 from the Graphostomataceae family was studied for potential anti-inflammatory and anticancer agents. A diverse array of natural products was identified. Six of which were undescribed compounds, including xylariterpenoids L-N, (1R,2S,6R,7S)-1,2-dihydroxy-α-bisabolol, 6-[(1R)-1-hydroxy-1-methyl-2-propenyl]-4-methoxy-3-methyl-2H-pyran-2-one and (1R*,4S*,5S*,7S*,10R*)-guaia-11 (12)-en-7,10-diol. Several of the isolated compounds such as bergamotene, guaiane and phthalide derivatives showed activity in both the inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells with IC₅₀ values in the range of 2.48-10.82 μg/mL and anti-proliferation against HeLa cells with IC₅₀ values in the range of 8.64-31.16 μg/mL. While compounds such as cerebrosides A and C only exhibited inhibitory effects on NO production with IC₅₀ values in the range of 4.45-10.28 μg/mL.

Germacrene A-A Central Intermediate in Sesquiterpene Biosynthesis

This review summarises known sesquiterpenes whose biosyntheses proceed through the intermediate germacrene A. First, the occurrence and biosynthesis of germacrene A in Nature and its peculiar chemistry will be highlighted, followed by a discussion of 6-6 and 5-7 bicyclic compounds and their more complex derivatives. For each compound the absolute configuration, if it is known, and the reasoning for its assignment is presented.

Efficient labeling of organic molecules using 13C elemental carbon: universal access to 13C2-labeled synthetic building blocks, polymers and pharmaceuticals

Synthetic methodology enabled by ¹³C-elemental carbon is reported. Calcium carbide Ca¹³C₂ was applied to introduce a universal ¹³C₂ unit in the synthesis of labeled alkynes, O,S,N-vinyl derivatives, labeled polymers and ¹³C₂-pyridazine drug core.

Volatiles from the hypoxylaceous fungi Hypoxylon griseobrunneum and Hypoxylon macrocarpum

The volatiles emitted by the ascomycetes Hypoxylon griseobrunneum and Hypoxylon macrocarpum (Hypoxylaceae, Xylariales) were collected by use of a closed-loop stripping apparatus (CLSA) and analysed by GC–MS. The main compound class of both species were polysubstituted benzene derivatives. Their structures could only be unambiguously determined by comparison to all isomers with different substitution patterns. The substitution pattern of the main compound from H. griseobrunneum, the new natural product 2,4,5-trimethylanisole, was explainable by a polyketide biosynthesis mechanism that was supported by a feeding experiment with (methyl-²H₃)methionine.

Volatiles from the tropical ascomycete Daldinia clavata (Hypoxylaceae, Xylariales)

The volatiles from the fungus Daldinia clavata were collected by use of a closed-loop stripping apparatus and analysed by GC-MS. A few compounds were readily identified by comparison of measured to library mass spectra and of retention indices to published data, while for other compounds a synthesis of references was required. For one of the main compounds, 5-hydroxy-4,6-dimethyloctan-3-one, the relative and absolute configuration was determined by synthesis of all eight stereoisomers and gas chromatographic analysis using a homochiral stationary phase. Another identified new natural product is 6-nonyl-2H-pyran-2-one. The antimicrobial and cytotoxic effects of the synthetic volatiles are also reported.

Harzianone Biosynthesis by the Biocontrol Fungus Trichoderma

Analysis of the volatile terpenes produced by seven fungal strains of the genus Trichoderma by use of a closed-loop stripping apparatus (CLSA) revealed a common production of harzianone, a bioactive, structurally unique diterpenoid consisting of a fused tetracyclic 4,7,5,6-membered ring system. The terpene cyclization mechanism was studied by feeding experiments using selectively ¹³ C- and ² H-labeled synthetic mevalonolactone isotopologues, followed by analysis of the incorporation patterns by ¹³ C NMR spectroscopy and GC/MS. The structure of harzianone was further supported from a ¹³ C,¹³ C COSY experiment of the in-vivo-generated fully ¹³ C-labeled diterpene.

Genome of Diaporthe sp. provides insights into the potential inter-phylum transfer of a fungal sesquiterpenoid biosynthetic pathway

Fungi have highly active secondary metabolic pathways which enable them to produce a wealth of sesquiterpenoids that are bioactive. One example is Δ6-protoilludene, the precursor to the cytotoxic illudins, which are pharmaceutically relevant as anticancer therapeutics. To date, this valuable sesquiterpene has only been identified in members of the fungal division Basidiomycota. To explore the untapped potential of fungi belonging to the division Ascomycota in producing Δ6-protoilludene, we isolated a fungal endophyte Diaporthe sp. BR109 and show that it produces a diversity of terpenoids including Δ6-protoilludene. Using a genome sequencing and mining approach 17 putative novel sesquiterpene synthases were identified in Diaporthe sp. BR109. A phylogenetic approach was used to predict which gene encodes Δ6-protoilludene synthase, which was then confirmed experimentally. These analyses reveal that the sesquiterpene synthase and its putative sesquiterpene scaffold modifying cytochrome P450(s) may have been acquired by inter-phylum horizontal gene transfer from Basidiomycota to Ascomycota. Bioinformatic analyses indicate that inter-phylum transfer of these minimal sequiterpenoid secondary metabolic pathways may have occurred in other fungi. This work provides insights into the evolution of fungal sesquiterpenoid secondary metabolic pathways in the production of pharmaceutically relevant bioactive natural products.