Antimicrobial Oligophenalenone Dimers from the Soil Fungus Talaromyces stipitatus.

New polyketide-derived oligophenalenone dimers, 9a-epi-bacillisporin E (1) and bacillisporins F-H (2-5), along with the known bacillisporin A (6), were isolated from the fungus Talaromyces stipitatus. Their structures and absolute configurations were determined on the basis of spectroscopic analyses, electronic circular dichroism, and GIAO NMR shift calculation followed by DP4 analysis. The antimicrobial activity of these compounds was evaluated against a panel of human pathogenic bacteria. Among them, bacillisporin H (5) exhibited antimicrobial activity together with modest cytotoxicity against HeLa cells.