Cyclooxygenase-2 inhibitory phenylbutenoids from the rhizomes of Zingiber cassumunar

Phenylbutenoids 1-6 isolated previously from the CHCl3 extracts of the rhizomes of Zingiber cassumunar, were evaluated for their cyclooxygenase-2 (COX-2) inhibitory activity along with a new isolate, 7 from the n-BuOH extracts of this plant. The COX-2 inhibitory assay was performed by measuring prostaglandin E-2 production in lipopolysaccharide-stimulated mouse macrophage RAW 264.7 cells. Two phenylbutenoid dimers, 1 and 2, exhibited considerable activity with IC50 values of 2.71 and 3.64 mu M. Two phenylbutenoid monomers, 3 and 4, showed moderate activity (IC50 14.97, 20.68 mu m, respectively). The other three phenylbutenoids, 5-7, were found to be inactive. Compound 7 was elucidated as a new phenylbutenoid glycoside, namely, (E)-4-(3,4-dimethoxy-phenyl)but-3-en-1-O-beta-D-glucopyranoside by spectral analysis including various 1D- and 2D-NMR experiments.