Geniculol, a new biologically active diterpene from the endophytic fungus Geniculosporium sp.

An endophytic fungus of the genus Geniculosporium was isolated from Teucriu m scorodonia. The EtOAc extract of this isolate exhibited antialgal activit ies, as well as demonstrating an interesting profile during chemical screen ing. After mass cultivation of this fungus, in an optimized agar medium, tw o of the compounds responsible for the observed biological activity were is olated, the new diterpene geniculol (1), and the known fungal metabolite cy tochalasin F (2). Geniculol is an unprecedented and irregular diterpenoid. For 1 and 2 complete H-1 and C-13 NMR data are reported. Both metabolites e xhibit algacidal properties. Additionally, cytochalasin F was shown to be a n inhibitor of photosynthesis, suggesting an ecological function in the pla nt-symbiont relationship for this secondary metabolite.