New Labdane diterpenes from Hedychium yunnanense with cytotoxicity and inhibitory effects on nitric oxide production

Two new labdane diterpenes, hedychenoids A (1) and B (2), were isolated from the rhizomes of Hedychium yunnanense, together with four known ones hedychenone (3), forrestin A (4), villosin (5) and calcaratarin C (6). Their structures were determined on the basis of NMR (1D and 2D) and mass spectroscopic analysis. Compounds 2, 3 and 5 exhibited cytotoxicity against SGC-7901 with IC₅₀ values of 14.88 ± 0.52, 7.08 ± 0.21 and 7.76 ± 0.21 μg/ml, 3 and 5 against HeLa with IC₅₀ values of 9.76 ± 0.48 and 13.24 ± 0.63 μg/ml, respectively. Compounds 2, 5 showed inhibitory effects against nitric oxide production in LPS and IFN-γ-induced RAW 264.7 murine macrophages with IC₅₀ values of 6.57 ± 0.88 and 5.99 ± 1.20 μg/ml, respectively.