title: Rhodocomatulin-Type Anthraquinones from the Australian Marine Invertebrates Clathria hirsuta and Comatula rotalaria.
abstract: Chemical investigations of an Australian sponge, Clathria hirsuta, from the Great Barrier Reef, have resulted in the isolation of two known anthraquinones, rhodocomatulin 5,7-dimethyl ether (1) and rhodocomatulin 7-methyl ether (2). Additionally, four new anthraquinone metabolites, 6-methoxyrhodocomatulin 7-methyl ether, 3-bromo-6-methoxy-12-desethylrhodocomatulin 7-methyl ether, 3-bromo-6-methoxyrhodocomatulin 7-methyl ether, and 3-bromorhodocomatulin 7-methyl ether (3-6), were also isolated and characterized. This is the first report of the rhodocomatulin-type anthraquinones from a marine sponge, as 1 and 2 were previously isolated from the marine crinoid genus Comatula. An additional chemical investigation of the marine crinoid Comatula rotalaria enabled the isolation of further quantities of 1 and 2, as well as two additional new crinoid metabolites, 12-desethylrhodocomatulin 5,7-dimethyl ether and 12-desethylrhodocomatulin 7-methyl ether (7 and 8). An NMR spectroscopic analysis of compounds 7 and 8 provided further insight into the rhodocomatulin planar structure and, together with the successful implementation of DFT-NMR calculations, confirmed that the rhodocomatulin metabolites existed as para rather than ortho quinones.
authors.affiliation: Eskitis Institute, Griffith University , Brisbane, QLD 4111, Australia.
authors.forename: Shahan
authors.initials: S
authors.lastname: Khokhar
authors.affiliation: Centre for Advanced Imaging, The University of Queensland , Brisbane, QLD 4072, Australia.
authors.forename: Gregory K
authors.initials: GK
authors.lastname: Pierens
authors.affiliation: Eskitis Institute, Griffith University , Brisbane, QLD 4111, Australia.|Queensland Museum , South Brisbane, QLD 4101, Australia.
authors.forename: John N A
authors.initials: JN
authors.lastname: Hooper
authors.affiliation: Queensland Museum , South Brisbane, QLD 4101, Australia.
authors.forename: Merrick G
authors.initials: MG
authors.lastname: Ekins
authors.affiliation: Eskitis Institute, Griffith University , Brisbane, QLD 4111, Australia.
authors.forename: Yunjiang
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Eskitis Institute, Griffith University , Brisbane, QLD 4111, Australia.
authors.forename: Rohan A
authors.initials: RA
authors.lastname: Davis
mesh_terms: D000818:Animals; D000880:Anthraquinones / Q000737:chemistry / Q000302:isolation & purification*; D001315:Australia; D004447:Echinodermata / Q000737:chemistry*; D008386:Marine Biology; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D018517:Plant Roots / Q000737:chemistry; D011161:Porifera / Q000737:chemistry*
chemical_list: D000880:Anthraquinones; C000610549:rhodocomatulin 7-methyl ether