title: [Studies on chemical constituents of Laurencia tristicha ( II )].
abstract: OBJECTIVE
  To search for chemical constituents with structural diversity from Laurencia tristicha to supply for biological assay.
  
  
  METHODS
  Compounds were isolated by means of column chromatography over normal phase silica gel and Sephadex LH-20, recrystallization and HPLC. Structures were identified by spectroscopic methods including 1D NMR, IR and MS. Cytotoxicities of the purified compounds were evaluated by MTT method.
  
  
  RESULTS
  Seven compounds were isolated from L. tristicha. Their structures were elucidated as cholesterol (1), cholesta- 5-en-3beta, 7alpha-diol (2), beta-stigmasterol (3), phytol (4), zeaxanthin (5), 4 -hydroxybenzaldehyde (6), indolyl-3-carbaldehyde (7). In the cytotoxic assay compound 2 was active against human cancer cell lines HCT-8, Bel-7402, BGc-823, A549 and HELA with IC50 values of 1.90, 2.02, 1.99, 6.52 and 1.20 microg x mL(-1), respectively. Compound 4 showed cytotoxicity against HCT-8 and HELA with IC50 value of 3.51 and 2.04 microg x mL(-1), and other compounds were inactive ( IC50 > 10 microg x mL(-1)).
  
  
  CONCLUSIONS
  Compounds 1-7 were isolated from L. tristicha for the first time. In additon, compounds 2 and 4 were cytotoxic against several human cancer cell lines.
authors.affiliation: College of Life Science, Ludong Univercity, Yantai 264025, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Sun
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Han
authors.forename: Run-Ya
authors.initials: RY
authors.lastname: Yang
authors.forename: Da-Yong
authors.initials: DY
authors.lastname: Shi
authors.forename: Zhao-Hui
authors.initials: ZH
authors.lastname: Uan
authors.forename: Jian-Gong
authors.initials: JG
authors.lastname: Shi
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D045744:Cell Line, Tumor / Q000187:drug effects; D002782:Cholestenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D002784:Cholesterol / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D006801:Humans; D020128:Inhibitory Concentration 50; D044722:Laurencia / Q000737:chemistry*; D010836:Phytol / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D002782:Cholestenes; C540791:cholesta-5-en-3,7-diol; D010836:Phytol; D002784:Cholesterol