Abstract:
Herein, we report the targeted isolation and characterization of
four linear nonribosomally synthesized tetrapeptides (pseudoxylaramide
A–D) and two cyclic nonribosomal peptide synthetase-
polyketide synthase-derived natural products (xylacremolide
A and B) from the termite-associated stowaway fungus
Pseudoxylaria sp. X187. The fungal strain was prioritized for
further metabolic analysis based on its taxonomical position
and morphological and bioassay data. Metabolic data were
dereplicated based on high-resolution tandem mass spectrometry
data and global molecular networking analysis. The
structure of all six new natural products was elucidated based
on a combination of 1D and 2D NMR analysis, Marfey’s analysis
and X-ray crystallography.
