title: Cytotoxic clerodane diterpenoids from the leaves and twigs of Casearia balansae.
abstract: Ten new clerodane diterpenoids (1-10), caseabalansins A-G, 18-epicaseabalansin A, 2-epicaseabalansin B, and 2-epicaseabalansin C, one new triterpenoid, balansinone (11), and seven known diterpenoids (12-18) were obtained from the leaves and twigs of Casearia balansae. Compounds 1 and 2 are the first examples of clerodane diterpenoids with an oxygen bridge between C-2 and C-19, and compounds 5-7 are three new diterpenoid artifacts presumably formed during the extraction process. The structures of the new compounds were established on the basis of extensive spectroscopic data, and that of 11 was verified by single-crystal X-ray crystallographic analysis. Compound 15 showed cytotoxic activity against the tumor cell lines PC3, DU145, SKOV3, and A549 with IC₅₀ values of 4.5, 4.3, 5.1, and 5.7 μM, respectively. Compounds 1a, 2a, and 4 showed selective activity against PC3 tumor cells.
authors.affiliation: Department of Natural Product Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University , 44 West Wenhua Road, Jinan 250012, People's Republic of China.
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.forename: Xiao-Ling
authors.initials: XL
authors.lastname: Wang
authors.forename: Shu-Qi
authors.initials: SQ
authors.lastname: Wang
authors.forename: Tao
authors.initials: T
authors.lastname: Shen
authors.forename: Yong-Qing
authors.initials: YQ
authors.lastname: Liu
authors.forename: Huiqing
authors.initials: H
authors.lastname: Yuan
authors.forename: Hong-Xiang
authors.initials: HX
authors.lastname: Lou
authors.forename: Xiao-Ning
authors.initials: XN
authors.lastname: Wang
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D037821:Casearia / Q000737:chemistry*; D018360:Crystallography, X-Ray; D045785:Diterpenes, Clerodane / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D004354:Drug Screening Assays, Antitumor; D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D006801:Humans; D020128:Inhibitory Concentration 50; D008968:Molecular Conformation; D015394:Molecular Structure; D018515:Plant Leaves / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D045785:Diterpenes, Clerodane; D004365:Drugs, Chinese Herbal