Diterpenoids from the Endophytic Fungus Botryosphaeria sp. P483 of the Chinese Herbal Medicine Huperzia serrata

Two new tetranorlabdane diterpenoids, named botryosphaerins G (1) and H (2), were isolated from the solid fermentation products of Botryosphaeria sp. P483 along with seven known tetranorlabdane diterpenes (3-9). Their structures were elucidated by extensive analysis, including 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS). Their absolute configuration was confirmed by single-crystal X-ray diffraction analyses using the anomalous scattering of Cu K radiation. All of the isolated compounds were tested for activity against phytopathogenic fungi and nematodes. Compounds 2 and 3 showed antifungal activity and compound 2 showed weak nematicidal activity.