title: New norclerodane diterpenoids from the tubers of Dioscorea bulbifera.
abstract: Phytochemical investigations of the tubers of Dioscorea bulbifera L. resulted in the isolation of nine norclerodane diterpenoids, including two new compounds, diosbulbins N (1) and P (3), a new naturally occurring compound, diosbulbin O (2), and six known ones, diosbulbins A-D, F and G (4-9). Their structures were established by spectroscopic and chemical methods. The absolute stereochemistry of 1 was determined by a modified Mosher's method, and the absolute configuration of 2 was determined by a single-crystal X-ray diffraction analysis with CuKα irradiation. Compounds 1-3 were evaluated for in vitro cytotoxicity against five human cancer cell lines.
authors.affiliation: Department of Pharmacy, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology.
authors.forename: Ying
authors.initials: Y
authors.lastname: Tang
authors.forename: Yong-bo
authors.initials: YB
authors.lastname: Xue
authors.forename: Lei
authors.initials: L
authors.lastname: Zhou
authors.forename: Jin-wen
authors.initials: JW
authors.lastname: Zhang
authors.forename: Guang-min
authors.initials: GM
authors.lastname: Yao
authors.forename: Zeng-wei
authors.initials: ZW
authors.lastname: Luo
authors.forename: Guang
authors.initials: G
authors.lastname: Du
authors.forename: Yong-hui
authors.initials: YH
authors.lastname: Zhang
mesh_terms: D018360:Crystallography, X-Ray; D027742:Dioscorea / Q000737:chemistry* / Q000378:metabolism; D045785:Diterpenes, Clerodane / Q000737:chemistry* / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D035281:Plant Tubers / Q000737:chemistry / Q000378:metabolism; D013237:Stereoisomerism
chemical_list: D045785:Diterpenes, Clerodane