New Pyridinone Alkaloid and Polyketide from the Cordyceps-Colonizing Fungus Pseudogymnoascus roseus

One new pyridinone alkaloid pseudogymnone A (<b>1</b>) and one new tricyclic polyketide penijanthinone C (<b>2</b>), together with six known compounds, harzianic acid (<b>3</b>), 3-methyl-2-(2-nonenyl)-4(1<i>H</i>)-quinolinone (<b>4</b>), emodic acid (<b>5</b>), alaternin (<b>6</b>), violaceol-I (<b>7</b>), and violaceol-II (<b>8</b>), were obtained from the <i>Cordyceps</i>-colonizing fungus <i>Pseudogymnoascus roseus</i>. The structures and absolute configurations of the isolated compounds were elucidated through a combination of NMR and MS spectroscopic analyses, ECD calculations, and X-ray crystallography. Compound <b>3</b> exhibited obvious cytotoxicity against A549 (IC₅₀ = 4.2 µM) and MGC (IC₅₀ = 3.8 µM) cell lines. Integrated network pharmacology and molecular docking analyses indicated that compound <b>3</b> exerts potential anti-gastric-cancer effects by modulating multiple cancer-related signaling pathways, with EGFR identified as a potential target of compound <b>3</b>.