title: Norsesquiterpenes from the brown alga Dictyopteris divaricata.
abstract: Three bisnorsesquiterpenes (1-3) with novel carbon skeletons and a norsesquiterpene (4) have been isolated from the brown alga Dictyopteris divaricata. By means of spectroscopic data including IR, HRMS, 1D and 2D NMR techniques, single-crystal X-ray diffraction, and CD, their structures including absolute configurations were proposed as (+)-(1R,6S,9R)-1-hydroxyl-6-isopropyl-9-methylbicyclo[4.3.0]non-4-en-3-one (1), (-)-(1S,6S,9R)-1-hydroxyl-6-isopropyl-9-methylbicyclo[4.3.0] non-4-en-3-one (2), (+)-(5S,6R,9S)-5-hydroxyl-6-isopropyl-9-methylbicyclo[4.3.0]non-1-en-3-one (3), and (-)-(1R,7S,10R)-1-hydroxy-11-norcadinan-5-en-4-one (4). Biogenetically, the carbon skeleton of 1-3 may be derived from the co-occurring cadinane skeleton by ring contraction and loss of two carbon units, and compound 4 from the oxidation of cadinane derivatives. Compounds 1-4 were inactive (IC50 > 10 microg/mL) against several human cancer cell lines including lung adenocarcinoma (A549), stomach cancer (BGC-823), breast cancer (MCF-7), hepatoma (Bel7402), and colon cancer (HCT-8) cell lines.
authors.affiliation: Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, People's Republic of China.
authors.forename: Fuhang
authors.initials: F
authors.lastname: Song
authors.forename: Xiuli
authors.initials: X
authors.lastname: Xu
authors.forename: Shuai
authors.initials: S
authors.lastname: Li
authors.forename: Sujuan
authors.initials: S
authors.lastname: Wang
authors.forename: Jielu
authors.initials: J
authors.lastname: Zhao
authors.forename: Peng
authors.initials: P
authors.lastname: Cao
authors.forename: Yongchun
authors.initials: Y
authors.lastname: Yang
authors.forename: Xiao
authors.initials: X
authors.lastname: Fan
authors.forename: Jiangong
authors.initials: J
authors.lastname: Shi
authors.forename: Lan
authors.initials: L
authors.lastname: He
authors.forename: Yang
authors.initials: Y
authors.lastname: Lü
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D002681:China; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D020128:Inhibitory Concentration 50; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D000459:Phaeophyceae / Q000737:chemistry*; D012717:Sesquiterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D013237:Stereoisomerism; D014407:Tumor Cells, Cultured
chemical_list: C504947:1-hydroxy-11-norcadinan-5-en-4-one; C504945:1-hydroxyl-6-isopropyl-9-methylbicyclo(4.3.0)non-4-en-3-one; C504946:5-hydroxyl-6-isopropyl-9-methylbicyclo(4.3.0)non-1-en-3-one; D000970:Antineoplastic Agents; D012717:Sesquiterpenes