title: Bioactive metabolites from the South African marine mollusk Trimusculus costatus.
abstract: A reinvestigation of extracts of the endemic South African intertidal limpet Trimusculus costatus yielded the known labdane diterpenes 6beta,7alpha-diacetoxylabda-8,13 E-dien-15-ol ( 1) and 2alpha,6beta,7alpha-triacetoxylabda-8,13 E-dien-15-ol ( 2) and three new metabolites, 6beta,7alpha,15-triacetoxylabda-8,13 E-diene ( 3), 3alpha,11-dihydroxy-9,11-seco-cholest-4,7-dien-6,9-dione ( 4), and cholest-7-en-3,5,7-triol ( 5). Chiral derivatization and X-ray analysis were used to confirm the labdane absolute configuration of 2. Compounds 1, 2 and 4 exhibited moderate activity (3-25 microM) against the WHCO1 human esophageal cancer cell line.
authors.affiliation: Department of Chemistry, Rhodes University, Grahamstown, South Africa.
authors.forename: Albert W W
authors.initials: AW
authors.lastname: van Wyk
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Gray
authors.forename: Catherine E
authors.initials: CE
authors.lastname: Whibley
authors.forename: Omolaja
authors.initials: O
authors.lastname: Osoniyi
authors.forename: Denver T
authors.initials: DT
authors.lastname: Hendricks
authors.forename: Mino R
authors.initials: MR
authors.lastname: Caira
authors.forename: Michael T
authors.initials: MT
authors.lastname: Davies-Coleman
mesh_terms: D000818:Animals; D018360:Crystallography, X-Ray; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D008386:Marine Biology; D008968:Molecular Conformation; D015394:Molecular Structure; D008974:Mollusca / Q000737:chemistry*; D013019:South Africa
chemical_list: D004224:Diterpenes