Cytotoxic Curvalarol C and Other Compounds from Marine Fungus Asteromyces cruciatus KMM 4696

The present study aimed to isolate new specialized metabolites from the obligate marine fungus Asteromyces cruciatus KMM 4696. The strain KMM 4696 was identified based on the 28S rRNA, ITS, and TEF1 molecular genetic markers. Chromatographic separation of the fungal extract obtained from KI-containing nutrient media cultivation led to the isolation of undescribed pentanorlanostanes curvalarols C (1) and D (2), as well as an undescribed 6/6/5 anthraquinone acruciquinone D (3), along with eight known metabolites. The structures of the isolated compounds were established based on 1D and 2D NMR and MS data. The cytotoxic activity of curvalarol C (1) was assessed in MCF-10A and MCF-7 cells. Curvalarol C exhibited selective activity against cancer MCF-7 cells and inhibiting colony formation with an IC₅₀ of 4.7 µM.