Cadinane sesquiterpenes from Curcuma phaeocaulis with their inhibitory activities on nitric oxide production in RAW 264.7 cells

Four new cadinane-type sesquiterpenes named phacadinanes A-D (1-4) were isolated from the rhizomes of Curcuma phaeocaulis. Their structures were elucidated by 1D and 2D NMR, as well as accurate mass measurements. Compound 4 was the first example of a rare 4,5-seco-cadinane sesquiterpene isolated from the Zingiberaceae family. Furthermore, inhibitory effects of the isolated compounds on nitric oxide production in LPS-activated macrophages were evaluated. Compounds 1 and 2 showed strong inhibitory activities on NO production with IC50 values of 3.88 +/- 058 and 225 +/- 0.71 mu M, respectively. A possible biogenetic pathway for 4,5-seco-cadinane sesquiterpene (4) was postulated. (C) 2015 Elsevier B.V. All rights reserved.