Hepatoprotective diterpenes from the nodes of Pinus massoniana

Three new diterpenes, named pinusins D-F (1-3), were isolated from the Chinese medicine "Pini Lignum Nodi" (the dried tuberculate or branched nodes of Pinus massoniana), along with twelve known diterpenes. The structures of these new compounds were determined using detailed spectroscopic methods and ECD calculations. Compounds 4-15 displayed moderate hepatoprotective activity against H2O2-induced oxidative damage in HepG2 cells, while compounds 5-15 exhibited markedly enhanced efficacy -surpassing that of bicyclol (positive control).