Abietane Diterpenoids\nfrom the Rhizomes of <i>Kaempferia roscoeana</i> and Their\nAnti-Inflammatory Activities

Six new abietane diterpenes, roscoeananes A–F\n(<b>1</b>–<b>6</b>), along with two known compounds\n(<b>7</b>–<b>8</b>) were isolated from the rhizomes\nof <i>Kaempferia roscoeana</i>. The structures of all compounds\nwere\nelucidated by analysis of spectroscopic data, and the absolute configurations\nwere assigned by a comparison of the theoretical and experimental\nelectronic circular dichroism (ECD) spectra and a comparison with\nliterature values. The unreported compound <b>5</b> is an ether-linked\ndimer of roscoeanane B (<b>2</b>). Most of the isolated compounds\nwere tested for their nitric oxide inhibitory effects in lipopolysaccharide-activated\nRAW264.7 cells. Among them, roscoeanane A (<b>1</b>) was found\nto reduce NO levels in murine macrophage cells with an IC<sub>50</sub> value of 3.58 ± 0.95 μM and exhibited low cytotoxicity\n(IC<sub>50</sub> > 50 μM).