Omnipolyphilins C and D and Mycoarpeptins A-D from a North American Mycoarthris Isolate

A soil-derived Mycoarthris sp. isolate yielded a combination of eight new and known secondary metabolites consisting of four cyclic tetrapeptides, omnipolyphilins A-D (1-4), and four lipopeptides, mycoarpeptins A-D (5-8). The structures of natural products 1-8 were established based on analysis of the HRESIMS, MS/MS fragmentation, and 1D and 2D NMR data. Their absolute configurations were determined using Marfey's analysis, chemical synthesis, and conformational analysis. Omnipolyphilins A-D (1-4) stand as a unique group of fungal cyclopeptides characterized by the presence of a hexahydropyrrolo[2,3-b]indole-2-carboxylic acid (HPIC) and 3-hydroxytyrosine (DOPA). Mycoarpeptins A-D (5-8) are acyclic lipopeptides featuring non-proteinogenic β-aminoisobutyric acid (BAIBA) residues. A survey of the metabolite profiles indicated the likelihood of regional and phylogenetic variation in the production of omnipolyphilins and mycoarpeptins.