Cytotoxic labdane-type diterpenes from Hedychium longipetalum inhibiting production of nitric oxide.

Three new labdane diterpenes, hedylongnoids A (1), B (2) and C (3), were isolated from the rhizomes of Hedychium longipetalum, together with three known ones yunnancoronarin A (4), hedyforrestin C (5) and hedyforrestin B (6). Their structures were established by spectroscopic analysis, including 2D-NMR spectroscopic techniques. Compounds 1-6 exhibited inhibitory effects against nitric oxide (NO) production in LPS and IFN-γ-induced RAW 264.7 murine macrophages with IC50 values ranging from 0.56 to 7.50 μg/ml, and 3-6 showed cytotoxicities against cancer cell lines SGC-7901 and Hela with IC50 values ranging from 6.21 to 14.53 μg/ml and from 6.58 to 14.83 μg/ml, respectively.