Antimicrobial metabolites produced by endophytic fungi associated with the leaves of Vochysia divergens .

Investigation of the endophytic fungi Nigrospora sphaerica , Nigrospora oryzae , and Pseudofusicoccum stromaticum MeOH fractions isolated from the leaves of Vochysia divergens , a medicinal species from the Brazilian Pantanal, led to the identification of five compounds, namely a new compound (1 E ,8 Z )-10,11-dihydroxy-5,5,8-trimethyl-4-oxocycloundeca-1,8-diene-1-carbaldehyde ( 1 ) and four known compounds: 5-methylmellein ( 2 ), sclerone ( 3 ), daldinone A ( 4 ), and lasiodiplodin ( 5 ). All compounds were identified using spectroscopic methods, and 1 was corroborated with mass spectrometry, while the known compounds were compared with data in the literature. The relative configuration of compound 1 was determined based on theoretical conformational studies as well as the J experimental values between the hydroxymethyne hydrogens. The antimicrobial activity of the compounds was evaluated. Promising results were obtained for compounds 2 , 4 , and 5 since they inhibited the bacterium Pseudomonas aeruginosa , an opportunistic pathogen, suggesting the potential of these microorganisms as a source of new antibacterial agents.