title: Antiproliferative compounds of Helmiopsis sphaerocarpa from the Madagascar rainforest.
abstract: Bioassay-directed separation of an ethanol extract of the leaves of Helmiopsis sphaerocarpa L.C. Barnett (Sterculiaceae) led to the isolation of the new compound 14alpha,15alpha-epoxy-3beta-hydroxytaraxerane (1) and the four known compounds taraxerol (2), stigmast-5-en-3-ol (3), 5alpha,8alpha-epidioxy-24(S)-methylcholesta-6,22-dien-3beta-ol (4), and 24xi-hydroperoxy-24-ethylcholesta-4,28(29)-dien-3-one (5). The structure of the new compound 1 was established on the basis of interpretation of its 1D and 2D NMR spectroscopic data. All the compounds were tested against A2780 human ovarian cancer cell lines, and compounds 4 and 5 showed mild antiproliferative activity, with IC(50) values of 16 and 7 microg mL(-1), respectively.
authors.affiliation: Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA. shugeng_cao@hms.harvard.edu
authors.forename: Shugeng
authors.initials: S
authors.lastname: Cao
authors.forename: Peggy
authors.initials: P
authors.lastname: Brodie
authors.forename: James S
authors.initials: JS
authors.lastname: Miller
authors.forename: Chris
authors.initials: C
authors.lastname: Birkinshaw
authors.forename: A
authors.initials: A
authors.lastname: Rakotondrafara
authors.forename: Rabodo
authors.initials: R
authors.lastname: Andriantsiferana
authors.forename: Vincent E
authors.initials: VE
authors.lastname: Rasamison
authors.forename: David G I
authors.initials: DG
authors.lastname: Kingston
mesh_terms: D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D000431:Ethanol; D005260:Female; D006801:Humans; D008270:Madagascar; D009682:Magnetic Resonance Spectroscopy; D019660:Malvaceae / Q000737:chemistry*; D015394:Molecular Structure; D010936:Plant Extracts / Q000302:isolation & purification* / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry*
chemical_list: D010936:Plant Extracts; D000431:Ethanol