Two new steroids with cytotoxicities from fungus Acrocalymma cycadis

Thirteen steroids (1–13), including two undescribed steroids, acrocalysterol C (1) and acrocalysterol D (2), were isolated from cultures of the fungus Acrocalymma cycadis using the OSMAC approach. Compounds 1 and 2 represent highly oxygenated steroids that contain an epoxy fragment. Through NMR and HRESIMS analyses, quantum chemical calculations, and electronic circular dichroism (ECD) experiments, their structures and absolute configurations were characterized. Then, the in vitro cytotoxicity of each compound was evaluated. Compounds 4 and 8-10 exhibited remarkable cytotoxicities against HeLa cells. Obviously, compound 10 exhibited twofold greater activity against HeLa than positive control, with IC50 values of 13.2 ± 1.23 μM. Additionally, compound 2 presented moderate potent cytotoxicity activities against three human cancer cells, comparable to the positive control. Thus, the bioactive metabolites of the strain A. cycadis may serve as a novel resource for development. [Display omitted] •Thirteen steroids were identified from the fungus Acrocalymma cycadis.•The absolute configurations of two new steroids were established based on NMR, HRESIMS, calculation ECD.•Compound 10 exhibited twofold greater activity against HeLa than positive control.•Compound 2 presented moderate potent cytotoxicities on three human cancer cells, verging on the positive control.