title: Cytotoxic 3,20-epoxy-ent-kaurane diterpenoids from Isodon eriocalyx var. laxiflora.
abstract: Four new ent-kaurane diterpenoids, laxiflorins J-M (1-4), along with maoecrystal A (5) and maoecrystal P (6), were isolated from the leaves of Isodon eriocalyx var. laxiflora. Their structures were determined by spectroscopic analyses. All the compounds were assayed for their cytotoxic effects on human tumor K562, A549, and T24 cell lines. Compounds 1 and 6 showed significant inhibitory effects on human tumor K562 and T24 cells, with IC(50) values less than 0.5 microg/mL. Compound 3 also demonstrated cytotoxic activities against all three types of human tumor cells, with IC(50) values in the range of 1-25 microg/mL.
authors.affiliation: State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, The Chinese Academy of Sciences, Kunming 650204, Yunnan, People's Republic of China.
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Niu
authors.forename: Sheng-Hong
authors.initials: SH
authors.lastname: Li
authors.forename: Shuang-Xi
authors.initials: SX
authors.lastname: Mei
authors.forename: Zhi
authors.initials: Z
authors.lastname: Na
authors.forename: Qin-Shi
authors.initials: QS
authors.lastname: Zhao
authors.forename: Zhong-Wen
authors.initials: ZW
authors.lastname: Lin
authors.forename: Han-Dong
authors.initials: HD
authors.lastname: Sun
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D002681:China; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D020128:Inhibitory Concentration 50; D037602:Isodon / Q000737:chemistry*; D020014:K562 Cells / Q000187:drug effects; D008175:Lung Neoplasms; D008968:Molecular Conformation; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D018515:Plant Leaves / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D004224:Diterpenes; C473434:maoecrystal A; C473436:maoecrystal P