title: Unique Polybrominated Hydrocarbons from the Australian Endemic Red Alga Ptilonia australasica.
abstract: The red alga Ptilonia australasica is endemic to Australian temperate waters. Chemical investigation of P. australasica led to the identification of four new polybrominated compounds, ptilones A-C (1-3) and australasol A (4). Their planar structures were established by extensive NMR and MS analyses. The low H/C ratio and the presence of a large number of heteroatoms made the structure elucidation challenging. The absolute configurations of 1, 2, and 4 were determined by quantum chemical ECD calculations employing time-dependent density functional theory. Ptilones A-C (1-3) show unique 4-ethyl-5-methylenecyclopent-2-enone (1 and 2) and 2-methyl-6-vinyl-4H-pyran-4-one (3) skeletons not previously reported in algal metabolites. Ptilone A displayed the most potent cytotoxicity against the human prostate cancer PC3 cells with an IC50 value of 0.44 μM and induced the PC3 cell cycle arrest in the G0/G1 phase.
authors.affiliation: Eskitis Institute for Drug Discovery, Griffith University , Brisbane, QLD 4111, Australia.
authors.forename: Trong D
authors.initials: TD
authors.lastname: Tran
authors.affiliation: Eskitis Institute for Drug Discovery, Griffith University , Brisbane, QLD 4111, Australia.
authors.forename: Ngoc B
authors.initials: NB
authors.lastname: Pham
authors.affiliation: Eskitis Institute for Drug Discovery, Griffith University , Brisbane, QLD 4111, Australia.
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Quinn
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D001315:Australia; D002453:Cell Cycle; D004354:Drug Screening Assays, Antitumor; D016193:G1 Phase; D006801:Humans; D006842:Hydrocarbons, Brominated / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D020128:Inhibitory Concentration 50; D008297:Male; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D011471:Prostatic Neoplasms / Q000188:drug therapy; D000461:Rhodophyta / Q000737:chemistry*
chemical_list: D000970:Antineoplastic Agents; D006842:Hydrocarbons, Brominated; C000610214:australasol A; C000610211:ptilone A; C000610212:ptilone B; C000610213:ptilone C