Volatiles from the xylarialean fungus Hypoxylon invadens

Abstract

The volatiles emitted by agar plate cultures of the xylarialean fungus Hypoxylon invadens were investigated by use of a closed loop stripping apparatus in combination with GC–MS. Several aromatic compounds were found that could only be identified by comparison to all possible constitutional isomers with different ring substitution patterns. For the set of identified compounds a plausible biosynthetic scheme was suggested that gives further support for the assigned structures.

Volatiles from the hypoxylaceous fungi Hypoxylon griseobrunneum and Hypoxylon macrocarpum

“…The main compounds released by H. macrocarpum were identified as 3,4-dimethoxytoluene ( 43 ) and 4-methylsalicylaldehyde ( 39 ), while 2,5-dimethylphenol ( 38 ) and 2-methoxy-4-methylbenzaldehyde ( 40 ) were detected in lower amounts. All four compounds were previously observed in the bouquet of H. invadens and unambiguously identified by comparison to all possible isomers with different ring substitution patterns [19]. Furthermore, comparison to all ten isomers of methoxy-methylbenzaldehydes described in this study allowed for the identification of another trace compound from H. macrocarpum as 3-methoxy-4-methylbenzaldehyde ( 41 ).…”

“…1,8-Dimethoxynaphthalene ( 27 ) was also found and has been reported previously from other Hypoxylon spp. [19,37]. The corresponding compound 1,8-dihydroxynaphthalene is a known precursor of fungal melanin pigments [38].…”

“…We have recently reported on two chlorinated aromatic compounds from an endophytic Geniculosporium sp. [18] and on a series of structurally related phenols, benzaldehydes and anisole derivatives from Hypoxylon invadens [19] that could only be identified with certainty following this approach of extensive compound comparisons. Members of the family Hypoxylaceae are regarded to be extremely rich in secondary metabolites [20], but not much is known about volatiles from these fungi [21].…”

Recent progress in biodiversity research on the Xylariales and their secondary metabolism

“…Moreover, this study also resulted in the recognition of Muscodor/Induratia and the related genus Emarcea as a unique phylogenetic lineage for which the new family Induratiaceae has been erected [117]. Interestingly, these fungi were never studied for the production of nonvolatile secondary metabolites and even the identity of the compounds that were detected by database aided GC-MS analytics often remains dubious [103,[118][119][120]. The Induratiaceae certainly deserve further studies of their secondary metabolome, including the identification of metabolites that show pronounced production in dual antagonist cultures.…”

Volatiles from the ascomyceteDaldinia cf. childiae(Hypoxylaceae), originating from China

“…The second most abundant volatile from D. clutidae was identified as 1,8-dimethoxynaphthalene (24). This compound has been previously reported from other fungi including D. eschscholtzii, 30 Hypoxylon invadens 31 and Hypoxylon griseobrunneum 32 that all belong to the family Hypoxylaceae. 33 The corresponding compound 1,8dihydroxynaphthalene (1,8-DHN), which is likely the biosynthetic precursor of 24, also serves as a building block of 1,8-DHN melanin in ascomycota.…”