Three New Derivatives of Zopfinol from <i>Pseudorhypophila Mangenotii</i> gen. et comb. nov.

<i>Triangularia mangenotti</i> was analyzed for the production of secondary metabolites, resulting in the isolation of known zopfinol (<b>1</b>) and its new derivatives zopfinol B–C (<b>2–4</b>), the 10-membered lactones 7-O-acetylmultiplolide A (<b>5</b>) and 8-O-acetylmultiplolide A (<b>6</b>), together with sordarin (<b>7</b>), sordarin B (<b>8</b>), and hypoxysordarin (<b>9</b>). The absolute configuration of <b>1</b> was elucidated by the synthesis of MPTA-esters. Compound <b>1</b> showed antimicrobial activity against the Gram-positive bacteria <i>Bacillus subtilis</i> and <i>Staphylococcus aureus</i> and the fungus <i>Mucor hiemalis</i>. While <b>4</b> was weakly antibacterial, <b>3</b> showed stronger antibiotic activity against the Gram-positive bacteria and weak antifungal activity against <i>M. hiemalis</i> and <i>Rhodotorula glutinis</i>. We furthermore observed the cytotoxicity of <b>1</b>, <b>3</b> and <b>4</b> against the mammalian cell lines KB3.1 and L929. Moreover, the new genus <i>Pseudorhypophila</i> is introduced herein to accommodate <i>Triangularia mangenotii</i> together with several species of <i>Zopfiella</i>—<i>Z. marina</i>, <i>Z. pilifera</i>, and <i>Z. submersa</i>. These taxa formed a well-supported monophyletic clade in the recently introduced family Navicularisporaceae, located far from the type species of the respective original genera, in a phylogram based on the combined dataset sequences of the internal transcribed spacer region (ITS), the nuclear rDNA large subunit (LSU), and fragments of the ribosomal polymerase II subunit 2 (<i>rpb2</i>) and β-tubulin (<i>tub2</i>) genes. <i>Zopfiella submersa</i> is synonymized with <i>P. marina</i> due to the phylogenetic and morphological similarity. The isolation of zopfinols <b>1</b>–<b>4</b> and sordarins <b>7</b>–<b>9</b> confirms the potential of this fungal order as producers of bioactive compounds and suggests these compounds as potential chemotaxonomic markers.