A New Record of Neohelicosporium guangxiense and Its Secondary Metabolites

In a diversity study of helicosporous hyphomycetes, a new record viz. Neohelicosporium guangxiense was collected, isolated and identified based on multi-gene phylogenetic analyses and morphological evidence. In this study, secondary metabolites of N. guangxiense were also investigated, from which four compounds were isolated and identified, including three α-tetralon derivatives (1-3) and one isocoumarin derivative (4). This is the first time that these compounds were isolated from the fungal genus Neohelicosporium, and compound 1 was firstly isolated from natural resources. Their structures were assigned based on the extensive 1D/2D NMR spectroscopic analyses, ESI-MS, and HR-ESI-MS measurements, especially the 2D NMR spectra of compound 1 were described in detail, and the absolute configuration of compound 1 was also elucidated for the first time. Furthermore, the bioactivities of all compounds were inactive in our bioassays.