title: ent-6,7-Secokaurane diterpenoids from Rabdosia serra and their cytotoxic activities.
abstract: Investigation of the hydrophobic extract of Rabdosia serra (Lamiaceae) led to the isolation of seven ent-6,7-secokaurane diterpenoids rabdosins E-K, along with twelve known ent-kaurane diterpenoids. Their structures were established by extensive spectroscopic analysis. The absolute configurations of rabdosins E, F, H and I were determined by single-crystal X-ray diffraction, with rabdosin E having a 3,20-epoxy group. These diterpenoids could be divided into two types according to their skeletons: rabdosins E-J are ent-6,20-epoxy-6,7-secokaur-1,7-olides, and rabdosin K is an ent-6,7-secokaur-7,20-olide. Cytotoxicity evaluation showed that serrin B, serrin A, isodocarpin and lushanrubescensin J exhibited weak to moderate cytotoxic activities (IC50<10μM) against two human cancer cell lines.
authors.affiliation: State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Zhangjiang Hi-Tech Park, Shanghai 201203, PR China.
authors.forename: Wen-Qiong
authors.initials: WQ
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Zhangjiang Hi-Tech Park, Shanghai 201203, PR China. Electronic address: ljxuan@mail.shcnc.ac.cn.
authors.forename: Li-Jiang
authors.initials: LJ
authors.lastname: Xuan
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D018360:Crystallography, X-Ray; D045786:Diterpenes, Kaurane / Q000737:chemistry; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D037602:Isodon / Q000737:chemistry*; D008968:Molecular Conformation; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D045786:Diterpenes, Kaurane
keywords: Cytotoxic activity; Lamiaceae; Rabdosia serra; ent-Kaurane diterpenoids