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.