title: Cytotoxicity of labdane-type diterpenoids from Hedychium forrestii.
abstract: Two new labdane-type diterpenoids, hedyforrestin D (1) and 15-ethoxy-hedyforrestin D (2), and three known compounds, yunnancoronarin A (4), B (3) and C (5) were isolated from the rhizomes of Hedychium forrestii. The structure of the new diterpenoids was established as 6beta,15xi-dihydroxylabda-8(17),11,13-trien-15,16-olide (1), and 6beta-hydroxy-15xi-ethoxylabda-8(17),11,13-trien-15,16-olide (2) on the basis of spectroscopic analyses. In addition, the isolated compounds were evaluated for their cytotoxicity against the lung adenocarcinoma cells A549 and leukemia cells K562 through 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assays. Of these, compounds 3 and 4 exhibited the most activity with IC(50) values of 0.92 and 2.20 microM, respectively, whereas 5 was inactive against A549 cells and 1 was inactive against both cell lines up to a concentration of 300.81 microM. This shows that both the hydroxy substitution and orientation of unsaturated lactone group in the five-membered ring of C-13 to C-16 seem to play an important role in the anti-tumor activities of human lung adenocarcinoma and leukemia.
authors.affiliation: State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, The Chinese Academy of Sciences, Heilongtan, Kunming, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhao
authors.forename: Chen
authors.initials: C
authors.lastname: Qing
authors.forename: Xiao Jiang
authors.initials: XJ
authors.lastname: Hao
authors.forename: Jun
authors.initials: J
authors.lastname: Han
authors.forename: Guo Ying
authors.initials: GY
authors.lastname: Zuo
authors.forename: Cheng
authors.initials: C
authors.lastname: Zou
authors.forename: Gui Li
authors.initials: GL
authors.lastname: Xu
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D045744:Cell Line, Tumor; D018360:Crystallography, X-Ray; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D020014:K562 Cells; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D021241:Spectrometry, Mass, Electrospray Ionization; D013055:Spectrophotometry, Infrared; D013329:Structure-Activity Relationship; D013778:Tetrazolium Salts; D013844:Thiazoles; D030521:Zingiberaceae / Q000737:chemistry*
chemical_list: C527314:15-ethoxy-hedyforrestin D; D000972:Antineoplastic Agents, Phytogenic; D004224:Diterpenes; D013778:Tetrazolium Salts; D013844:Thiazoles; C527315:hedyforrestin D; C433017:labdane; C022616:thiazolyl blue