Recebido em 18/12/2018; aceito em 29/04/2019; publicado na web em 16/05/2019 The upscaling of Xylaria cubensis, an endophyte of Eugenia brasiliensis (Myrtaceae), in PDB medium led to the isolation of known compounds including cytochalasin D (7) and cytochalasin C (8), which exhibited relatively higher phytotoxic activity in all the concentrations tested compared to the commercial herbicide GOAL ®. Besides the aforementioned metabolites, one diketopiperazine (DKP) and two isocoumarins were isolated and two DKPs were also identified in the mixture. The structures were determined by 1D and 2D 1 H NMR, MS analyses and were compared with the literature.
Chemical investigation of the crude PDB extract obtained from the endophytic fungus Schizophyllum commune afforded the pure substances, cyclo(L-Pro-L-Val) (1), uracil (2), cyclo(Pro-Tyr) (3), p-hydroxybenzoic acid (4) and a mixture of Rel.cyclo(Pro-Phe) (5) and Rel.cyclo(Pro-Ile) (6). When cultured in corn, the extract of this fungus yielded N-(2-phenylethyl) acetamide (7) and N-(4-hydroxyphenylethyl) acetamide (8). The structures of all compounds were determined based on the analyses of their MS, 1D and 2D-NMR spectroscopic data. Analysis of the crude extracts obtained from small-scale cultures (in PBD, YM, Nutrient, Czapek, Malt Extract, Corn and Rice) and a large-scale culture (in PDB) by mass spectrometry showed the presence of diketopiperazines 1, 3, 5 and 6. The crude extracts showed promising antioxidant, antifungal and acetylcholinesterase (AChE) inhibitory activities. The metabolites 7 and 8 showed antifungal and AChE inhibitory activities in vitro. This is the first report of the identification and isolation of diketopiperazines, arylethylamides, p-hydroxybenzoic acid in endophytic fungus of the Schizophyllum genus.
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