Microporenic Acids A–G, Biofilm Inhibitors, and Antimicrobial Agents from the Basidiomycete Microporus Species

The need for effective compounds to combat antimicrobial resistance and biofilms which play important roles in human infections continues to pose a major health challenge. Seven previously undescribed acyclic diterpenes linked to isocitric acid by an ether linkage, microporenic acids A-G (1-7), were isolated from the cultures of a hitherto undescribed species of the genus Microporus (Polyporales, Basidiomycota) originating from Kenya's Kakamega forest. Microporenic acids D and E (4 and 5) showed antimicrobial activity against a panel of Gram positive bacteria and a yeast, Candida tenuis. Moreover, microporenic acids A and B (1 and 2) demonstrated dose-dependent inhibition of biofilm formation by Staphylococcus aureus. Compound 1 further showed significant activity against Candida albicans and Staphylococcus aureus preformed biofilms.