title: Bioactive isomalabaricane triterpenes from the marine sponge Rhabdastrella globostellata.
abstract: Two new isomalabaricane triterpenes, stellettin H (1) and stellettin I (2), have been isolated from the marine sponge Rhabdastrella globostellata, collected from the Philippines. Stellettins A-D (3-6), (-)-stellettin E (7), and rhabdastrellic acid-A (8) were also isolated and characterized. Stellettin B (4) and (-)-stellettin E (7) showed selective cytotoxicity toward p21(WAF1/Cip1)-deficient human colon tumor (HCT-116) cells with IC(50) values of 0.043 and 0.039 microM, respectively.
authors.affiliation: Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, USA.
authors.forename: Deniz
authors.initials: D
authors.lastname: Tasdemir
authors.forename: Gina C
authors.initials: GC
authors.lastname: Mangalindan
authors.forename: Gisela P
authors.initials: GP
authors.lastname: Concepción
authors.forename: Sheryl M
authors.initials: SM
authors.lastname: Verbitski
authors.forename: Sridhar
authors.initials: S
authors.lastname: Rabindran
authors.forename: Miriam
authors.initials: M
authors.lastname: Miranda
authors.forename: Michael
authors.initials: M
authors.lastname: Greenstein
authors.forename: John N A
authors.initials: JN
authors.lastname: Hooper
authors.forename: Mary Kay
authors.initials: MK
authors.lastname: Harper
authors.forename: Chris M
authors.initials: CM
authors.lastname: Ireland
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D003110:Colonic Neoplasms; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000235:genetics; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D020128:Inhibitory Concentration 50; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010679:Philippines; D011161:Porifera / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism; D014315:Triterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D014315:Triterpenes; C452212:stellettin B; C452210:stellettin H; C452211:stellettin I