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Keywords:

  • Cladosporium uredinicola;
  • Psidium guajava;
  • Depsides;
  • Antimicrobial activity

Abstract

Four depsides, all of them new as natural products, were isolated from Cladosporium uredinicola solid-media culture and identified as 3-hydroxy-2,5-dimethylphenyl 2,4-dihydroxy-3,6-dimethylbenzoate (1), 3-hydroxy-2,4,5-trimethylphenyl 2,4-dihydroxy-3,6-dimethylbenzoate (2), 3-hydroxy-2,5-dimethylphenyl 3-[(2,4-dihydroxy-3,6-dimethylbenzoyl)oxy]-6-hydroxy-2,4-dimethylbenzoate (3), and 3-hydroxy-2,4,5-trimethylphenyl 3-[(2,4-dihydroxy-3,6-dimethylbenzoyl)oxy]-6-hydroxy-2,4-dimethylbenzoate (4). The endophytic fungus was isolated from Psidium guajava fruits and cultivated over sterilized rice. The compounds 14 were purified by classical chromatographic procedures, and the chemical structures were identified by spectroscopic studies, mainly 1D- and 2D-NMR and LC/ESI-MS/MS. Three of the isolated depsides exhibited moderate bacteriostatic and/or bactericide effects on Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus subtillis.