title: Cytotoxic and antiproliferative constituents from Dictyota ciliolata, Padina sanctae-crucis and Turbinaria tricostata.
abstract: BACKGROUND
  The hexane extracts of Dictyota ciliolata Sonder ex Kützing (Dictyotaceae), Padina sanctae-crucis Børgesen (Dictyotaceae), and Turbinaria tricostata E.S. Barton (Sargassaceae) were found to exhibit cytotoxic and antiproliferative activities in vitro. Bioactive compounds responsible for these activities have not been studied in detail for these species and phytochemical studies are very limited.
  
  
  OBJECTIVE
  Isolate, evaluate, and elucidate the bioactive constituents of D. ciliolata, P. sanctae-crucis, and T. tricostata.
  
  
  METHODS
  Bioassay-guided cytotoxicity fractionations using the Hep-2 cell line of the hexane extracts from these brown algae were analyzed using various chromatographic techniques. Cytotoxic and antiproliferative activities of all isolated compounds were also evaluated on a panel of cell lines (KB, Hep-2, MCF-7, and SiHa). Furthermore, their selectivity index, the ratio of cytotoxicity on normal cells to cancer cells, was evaluated using the HEK-293 cell line.
  
  
  RESULTS
  Four compounds were isolated from studied species: two sterol, fucosterol (1) and 24ξ-hydroperoxy-24-vinylcholesterol (2); and two diterpenes, pachydictyol A (3) and dictyol B acetate (4). The major bioactive components of the hexane extracts of T. tricostata and P. sanctae-crucis were compounds 1 and 2 (with CC50 varying around 3.1-25.6 µg/mL) on cell lines tested. Whereas compounds 1, 3, and 4 showed cytotoxic activity against cancer cell lines (CC50 varying between 14.8 and 41.2 µg/mL) and were major bioactive constituents of hexane extract of D. ciliolata. Compounds 1 and 4 showed antiproliferative activity on MCF-7 (IC50 = 43.3 µg/mL for compound 1 and 38.3 µg/mL for compound 2) and SiHa (IC50 = 43.3 µg/mL for compound 1 and 38.3 µg/mL for compound 2) cell lines.
  
  
  CONCLUSIONS
  This study is the first investigation on the bioactive components of D. ciliolata, P. sanctae-crucis, and T. tricostata. Although compounds 1-3 were described previously, the pharmacological activity of compound 4 is presented here for the first time.
authors.affiliation: Department of Marine Resources, Cinvestav, Unidad Mérida , Yucatán , México and.
authors.forename: Edgar
authors.initials: E
authors.lastname: Caamal-Fuentes
authors.forename: Rosa
authors.initials: R
authors.lastname: Moo-Puc
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Freile-Pelegrín
authors.forename: Daniel
authors.initials: D
authors.lastname: Robledo
mesh_terms: D049109:Cell Proliferation / Q000187:drug effects*; D003603:Cytotoxins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D057809:HEK293 Cells; D006801:Humans; D061986:MCF-7 Cells; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D012624:Seaweed
chemical_list: D003603:Cytotoxins; D010936:Plant Extracts
keywords: Cytotoxicity; Dictyotaceae; Sargassaceae; diterpenes; sterols