title: Chemical constituents of the red alga Laurencia tristicha.
abstract: Six new sesquiterpenes, 10-hydroxy-epiaplysin (1), 10-hydroxy-aplysin (2), 10-hydroxy-debromoepiaplysin (3), aplysin-9-ene (4), epiaplysinol (5) and debromoepiaplysinol (6), together with 13 known compounds (7-19), have been isolated from the red alga Laurencia tristicha. The structures of 1-6 were determined by spectroscopic methods including IR, EI-MS, HREI-MS, and 1D and 2D NMR techniques. All compounds were obtained from this species for the first time and were tested for cytotoxic activities against several human cancer cell lines including lung adenocarcinoma (A549), stomach cancer (BGC-823), hepatoma (Bel 7402), colon cancer (HCT-8) and HeLa cell lines. Compound 6 showed selective cytotoxicity against HeLa cell line with IC(50) 15.5 microM, cholest-5-en-3beta,7alpha-diol (14) was toxic to all tested cell lines with IC(50) values of 16.8, 5.1, 0.5, 0.5, and 0.3 microM, respectively, and other compounds were inactive (IC(50)>10 microg/ml).
authors.affiliation: Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Sun
authors.forename: Da-Yong
authors.initials: DY
authors.lastname: Shi
authors.forename: Shuai
authors.initials: S
authors.lastname: Li
authors.forename: Su-Juan
authors.initials: SJ
authors.lastname: Wang
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Han
authors.forename: Xiao
authors.initials: X
authors.lastname: Fan
authors.forename: Yong-Chun
authors.initials: YC
authors.lastname: Yang
authors.forename: Jian-Gong
authors.initials: JG
authors.lastname: Shi
mesh_terms: D045744:Cell Line, Tumor; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D000461:Rhodophyta / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization