New Labdane diterpenes from <i>Hedychium yunnanense</i> with cytotoxicity and inhibitory effects on nitric oxide production

<p>Two new labdane diterpenes, hedychenoids A (<b>1</b>) and B (<b>2</b>), were isolated from the rhizomes of <i>Hedychium yunnanense</i>, together with four known ones hedychenone (<b>3</b>), forrestin A (<b>4</b>), villosin (<b>5</b>) and calcaratarin C (<b>6</b>). Their structures were determined on the basis of NMR (1D and 2D) and mass spectroscopic analysis. Compounds <b>2</b>, <b>3</b> and <b>5</b> exhibited cytotoxicity against SGC-7901 with IC<sub>50</sub> values of 14.88 ± 0.52, 7.08 ± 0.21 and 7.76 ± 0.21 μg/ml, <b>3</b> and <b>5</b> against HeLa with IC<sub>50</sub> values of 9.76 ± 0.48 and 13.24 ± 0.63 μg/ml, respectively. Compounds <b>2</b>, <b>5</b> showed inhibitory effects against nitric oxide production in LPS and IFN-γ-induced RAW 264.7 murine macrophages with IC<sub>50</sub> values of 6.57 ± 0.88 and 5.99 ± 1.20 μg/ml, respectively.</p>