title: Cytotoxic 7,20-epoxy ent-kauranoids from Isodon xerophilus.
abstract: Four 7,20-epoxy ent-kaurane diterpenoids, xerophilusins G (1) and I-K (2-4), were isolated from the leaves of Isodon xerophilus, along with four known ones, enanderianin C (5), rosthorin A (6), longikaurin B (7), and rabdoternin D (8). Their structures were determined primarily using NMR spectroscopic techniques. The structure and stereochemistry of 3 were confirmed by X-ray crystallography. Compounds 4 and 7 exhibited broad cytotoxicity against four kinds of human tumor cells (K562, HL-60, HCT, and MKN-28 cells) in the range of 2.23-15.35 and 0.30-8.61 microg/ml, respectively.
authors.affiliation: Laboratory of Phytochemistry, Kunming Institute of Botany, Academia Sinica, Kunming 650204, Yunnan, People's Republic of China.
authors.forename: A J
authors.initials: AJ
authors.lastname: Hou
authors.forename: Q S
authors.initials: QS
authors.lastname: Zhao
authors.forename: M L
authors.initials: ML
authors.lastname: Li
authors.forename: B
authors.initials: B
authors.lastname: Jiang
authors.forename: Z W
authors.initials: ZW
authors.lastname: Lin
authors.forename: H D
authors.initials: HD
authors.lastname: Sun
authors.forename: Y P
authors.initials: YP
authors.lastname: Zhou
authors.forename: Y
authors.initials: Y
authors.lastname: Lu
authors.forename: Q T
authors.initials: QT
authors.lastname: Zheng
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity; D018360:Crystallography, X-Ray; D004224:Diterpenes / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity; D045786:Diterpenes, Kaurane; D004354:Drug Screening Assays, Antitumor; D019686:Lamiaceae / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008958:Models, Molecular; D008968:Molecular Conformation; D010947:Plants, Toxic / Q000737:chemistry*
chemical_list: C441198:7,20-epoxy ent-kaurane; D000972:Antineoplastic Agents, Phytogenic; D004224:Diterpenes; D045786:Diterpenes, Kaurane