title: Pyrroloacridine alkaloids from Plakortis quasiamphiaster: structures and bioactivity.
abstract: A re-collection of Plakortis quasiamphiaster from Vanuatu in 2003 resulted in the isolation of three known compounds, plakinidine A (1) and amphiasterins B1 (6) and B2 (7). Also isolated was a new bis-oxygenated pyrroloacridine alkaloid, plakinidine E (8), with a unique O-substitution versus N-substitution at position C-12 in 1. The biological evaluation of the active compounds in two assays provided complementary data. Plakinidine A (1) exhibited cytotoxicity against human colon H-116 cells with an IC50 of 0.23 microg/mL, but there were no effects against the yeast Saccharomyces cerevisiae diploid homozygous deletion strain of topoisomerase I (top1Delta). By contrast, 8 was inactive against H-116 cells but was potent in the yeast halo screen.
authors.affiliation: Department of Chemistry and Biochemistry, Institute of Marine Sciences, University of California, Santa Cruz, California 95064, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Ralifo
authors.forename: Laura
authors.initials: L
authors.lastname: Sanchez
authors.forename: Nadine C
authors.initials: NC
authors.lastname: Gassner
authors.forename: Karen
authors.initials: K
authors.lastname: Tenney
authors.forename: R Scott
authors.initials: RS
authors.lastname: Lokey
authors.forename: Theodore R
authors.initials: TR
authors.lastname: Holman
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Valeriote
authors.forename: Phillip
authors.initials: P
authors.lastname: Crews
mesh_terms: D000470:Alkaloids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D020128:Inhibitory Concentration 50; D015394:Molecular Structure; D047229:Plakortis / Q000737:chemistry*; D012441:Saccharomyces cerevisiae / Q000187:drug effects; D009514:Vanuatu
chemical_list: D000470:Alkaloids; D000970:Antineoplastic Agents