Guanacastane-type diterpenoids from Coprinus radians

► Radianspenes A-M with guanacastane skeleton were isolated from Coprinus radians M65. ► Radianspene M represents a dimeric diterpenoid besides ent-kaurane dimer. ► The structure of radianspene M was confirmed by X-ray diffraction analysis. ► Radianspene C shows cytotoxicity to MDA-MB-435 with IC50 of 0.91 μM.