Triterpene Glycosides Tricycloiridals A–D with Cytotoxicity Isolated from Fungus Chrysosporium sp. YX1242

Keratinophilic fungi are significant pathogens that cause dermatomycoses. Here, we report the discovery of four novel triterpene glycosides, tricycloiridals A–D (1–4), from the keratinophilic fungus Chrysosporium sp. YX1242, guided by mass-spectrometry-based molecular networking. Their structures, featuring unprecedented triterpene skeletons, were elucidated through comprehensive NMR, HRESIMS, and Snatzke’s and advanced Mosher’s methods. Notably, compound 1 exhibited potent cytotoxicity against human keratinocytes HaCaT (IC50 = 2.50 ± 0.2 μM), suggesting a potential role as a virulence factor in fungal pathogenesis. Additionally, bioinformatic analysis was used to predict the biosynthetic gene cluster responsible for these triterpene glycosides.