Dentifragilones A-B and Other Benzoic Acid Derivatives from the European Basidiomycete Dentipellis fragilis .

A chemical and biological exploration of the European polypore Dentipellis fragilis afforded two previously undescribed natural products ( 1 and 2 ), together with three known derivatives ( 3 - 5 ). Chemical structures of the isolated compounds were confirmed through 1D/2D NMR spectroscopic analyses, mass spectrometry, and by comparison with the reported literature. The relative and absolute configurations of 1 were determined according to the ROESY spectrum and time-dependent density functional theory electronic circular dichroism (TDDFT-ECD), respectively. Furthermore, the absolute configuration of dentipellinol ( 3 ) was revisited and revealed to be of ( R ) configuration. All the isolated compounds were assessed for their cytotoxic and antimicrobial activities, with some being revealed to have weak to moderate antimicrobial activity, particularly against Gram-positive bacteria.