<i>p</i>‑Terphenyl Derivatives from the Endolichenic Fungus <i>Floricola striata</i>

Ten new <i>p</i>-terphenyl derivatives, floricolins A–J (<b>1</b>–<b>10</b>), together with six known compounds (<b>11</b>–<b>16</b>), were isolated from the extract of the endolichenic fungus <i>Floricola striata</i>. Chemical structures of these compounds were elucidated using spectroscopic data (HRESIMS and NMR). Among them, <b>9</b> and <b>10</b> were enantiomeric mixtures, and their configurations were established by single-crystal X-ray diffraction analysis using Cu Kα radiation. Evaluation of the isolated compounds against <i>Candida albicans</i> revealed that the most active compound, <b>3</b> (MIC 8 μg/mL), exerted fungicidal action by destruction of the cell membrane

Tetramic Acids and Pyridone Alkaloids from the Endolichenic Fungus <i>Tolypocladium cylindrosporum</i>

Three new tetramic acid derivatives, tolypocladenols A₁, A₂, and B (<b>1</b>–<b>3</b>), a new pyridone alkaloid, tolypyridone A (<b>4</b>), and a new coumarin derivative, 3,8-dihydroxy-4-(4-hydroxyphenyl)-6-methylcoumarin (<b>5</b>), together with four known compounds (<b>6</b>–<b>9</b>) were isolated from the endolichenic fungus <i>Tolypocladium cylindrosporum</i>, which inhabits the lichen <i>Lethariella zahlbruckneri</i>. Structures of these compounds were determined by comprehensive analysis of spectroscopic data and single-crystal X-ray diffraction determination. Bioassay of the isolated compounds found that pyridoxatin (<b>7</b>) was cytotoxic to human cancer cells by induction of G0/G1 cell cycle arrest and apoptosis

Heptaketides from an Endolichenic Fungus <i>Biatriospora</i> sp. and Their Antifungal Activity

Twelve new heptaketides, biatriosporins A–L (<b>1</b>–<b>12</b>), biatriosporin M (<b>13</b>) (a ramulosin derivative), and 19 known compounds (<b>14</b>–<b>32</b>) were isolated from the endolichenic fungus <i>Biatriospora</i> sp. (8331C). The structures of these compounds were determined by analyzing MS and NMR data. The absolute configurations of compounds <b>1</b>, <b>2</b>, <b>7</b>, and <b>9</b> were determined by single-crystal X-ray diffraction analysis, whereas compound <b>10</b> was deduced with Mosher’s method. Four of the compounds were active in an antifungal assay. The most potent compound, compound <b>4</b>, also sensitized clinically derived azole-resistant <i>Candida albicans</i> strains to fluconazole (FLC). A mechanistic investigation revealed that <b>4</b> inhibited the function of efflux pumps and reduced the transcriptional expression of the efflux-pump-related genes <i>CDR1</i> and <i>CDR2</i>