Labdane and Tetranorlabdane Diterpenoids from Botryosphaeria sp. MHF, an Endophytic fungus of Maytenus hookeri

Five new diterpenoids, named botryosphaerins A–E ( 1 – 5 , resp.), including one labdane and four tetranorlabdane diterpenes, were isolated from the solid culture of the endophytic fungal strain Botryosphaeria sp. MHF of Maytenus hookeri , together with seven known diterpenoids, namely 13,14,15,16‐tetranorlabd‐7‐ene‐19,6 β  : 12,17‐diolide ( 6 ), acrostalidic acid ( 7 ), acrostalic acid ( 8 ), agathic acid ( 9 ), isocupressic acid ( 10 ), LL‐Z1271 β ( 11 ), and CJ‐14445 ( 12 ). The structures of all compounds were established on the basis of comprehensive spectroscopic studies. The relative configurations of 1 and 2 were determined by single‐crystal X‐ray diffraction analyses. All compounds except 4 were evaluated for their inhibitory activities against several pathogenic bacterial and fungal strains. However, only compound 12 showed significant inhibitions against Candida albicans, Saccharomyces cerevisiae , and Penicillium avellaneum UC‐4376 with nystatin as a positive control.