title: Pseudoceramines A-D, new antibacterial bromotyrosine alkaloids from the marine sponge Pseudoceratina sp.
abstract: Bioassay-guided fractionation of the CH(2)Cl(2)/MeOH extract of the Australian marine sponge Pseudoceratina sp. resulted in the purification of four new bromotyrosine alkaloids, pseudoceramines A-D (1-4), along with a known natural product, spermatinamine (5). The structures of 1-5 were determined by spectroscopic methods. Pseudoceramines A (1) and B (2) feature a rare bromotyrosyl-spermine-bromotyrosyl sequence, and pseudoceramine C (3) is the first example of bromotyrosine coupled with an N-methyl derivative of spermidine. Compounds 1-5 were screened for inhibition of toxin secretion by the type III secretion (T3S) pathway in Yersinia pseudotuberculosis. Compounds 2 and 5 inhibited secretion of the Yersinia outer protein YopE (IC(50) = 19 and 6 μM, respectively) and the enzyme activity of YopH (IC(50) = 33 and 6 μM, respectively).
authors.affiliation: Eskitis Institute, Griffith University, Brisbane, QLD 4111, Australia.
authors.forename: Sheng
authors.initials: S
authors.lastname: Yin
authors.forename: Rohan A
authors.initials: RA
authors.lastname: Davis
authors.forename: Todd
authors.initials: T
authors.lastname: Shelper
authors.forename: Melissa L
authors.initials: ML
authors.lastname: Sykes
authors.forename: Vicky M
authors.initials: VM
authors.lastname: Avery
authors.forename: Mikael
authors.initials: M
authors.lastname: Elofsson
authors.forename: Charlotta
authors.initials: C
authors.lastname: Sundin
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Quinn
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification*; D015394:Molecular Structure; D011161:Porifera / Q000737:chemistry*; D013237:Stereoisomerism; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; C475724:bromotyrosine; D014443:Tyrosine