Pimarane diterpenes from the fungus Epicoccum sp. HS-1 associated with Apostichopus japonicus

Three new pimarane diterpenes (1, 2 and 3) as well as a known compound 4, were isolated from the marine-derived fungus HS-1 from Apostichopus japonicus. Their structures and relative stereochemistry of 1-3 were elucidated using a combination of NMR spectroscopy and CD. In the primary bioassay, compounds 1, 2 and 4 inhibited the growth of KB and KBv200 with IC(50) of 3.51, 2.34 μg/mL, 20.74, 14.47 μg/mL, and 3.86, 6.52 μg/mL,...