title: Diterpenoids with diverse skeletons from the roots of Euphorbia micractina.
abstract: Twelve new minor diterpenoids, possessing 5/6/8 (1 and 2), 5/6/7/3 (3-9), and 5/6/6/4 (10-12) fused-ring skeletons, as determined by spectroscopic analysis, were isolated from an ethanol extract of the roots of Euphorbia micractina, together with 25 known compounds. The structures of the diterpene skeletons are rare and have been found only in compounds isolated from Euphorbia micractina and Euphorbia villosa. On the basis of the octant rule for cyclohexanones, the absolute configurations of 1-12, as well as of the known euphactins A-D and euphoractins A-D (13-15), could be assigned by circular dichroism spectroscopy. In addition, the co-occurring jolkinol B (16) was chemically transformed to euphoractin E (17), supporting the absolute configuration assignment and the biogenetic relationship between the different types of diterpenes. Compound 9 showed activity against HIV-1 replication in vitro, with an IC50 value of 8.8 ± 0.6 μM.
authors.affiliation: State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, People's Republic of China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Tian
authors.forename: Wendong
authors.initials: W
authors.lastname: Xu
authors.forename: Chenggen
authors.initials: C
authors.lastname: Zhu
authors.forename: Sheng
authors.initials: S
authors.lastname: Lin
authors.forename: Ying
authors.initials: Y
authors.lastname: Guo
authors.forename: Jiangong
authors.initials: J
authors.lastname: Shi
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D003512:Cyclohexanones / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D004224:Diterpenes / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D004354:Drug Screening Assays, Antitumor; D004365:Drugs, Chinese Herbal / Q000737:chemistry; D028481:Euphorbia / Q000737:chemistry*; D015497:HIV-1 / Q000187:drug effects; D020128:Inhibitory Concentration 50; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D018517:Plant Roots / Q000737:chemistry
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D003512:Cyclohexanones; D004224:Diterpenes; D004365:Drugs, Chinese Herbal; C036468:cyclohexanone; C042195:jolkinol B