Bioactive Spirocyclic C‐Arylglycosides From the Fungal–Fungal Co‐Culture of Pestalotiopsis sp. and Nigrospora sp.

In this study, two new papulacandin analogs (1-2), together with 12 known compounds (3-14), were identified from the co-culture of two endophytic fungi, Pestalotiopsis sp. J025 and Nigrospora sp. Wn-2-2, which were isolated from Wikstroemia nutans Champ. ex Benth. The aim of this study is to investigate the antifungal activity of papulacandins and other secondary metabolites from the co-culture of two endophytic fungi. Their chemical structures, including relative configurations, were elucidated using extensive spectroscopic analyses, including HRESIMS, 1D and 2D NMR, ECD calculations, and quantum mechanical-NMR calculations, as well as comparison with reported analogs. Compound 3 demonstrated promising in vitro antifungal activity against fluconazole-resistant Candida albicans with a minimum inhibitory concentration in 50% isolates (MIC50) of 0.57 ± 0.01 μM. These findings demonstrate that the papulacandin family is a promising resource for the development of antifungal agents against invasive Candida infections.