Semisynthesis and Cytotoxic Evaluation of an Ether Analogue Library Based on a Polyhalogenated Diphenyl Ether Scaffold Isolated from a Sponge.

The known oxygenated polyhalogenated diphenyl ether, 2-(2',4'-dibromophenoxy)-3,5-dibromophenol (), with previously reported activity in multiple cytotoxicity assays was isolated from the sponge sp. and proved to be an amenable scaffold for semisynthetic library generation. The phenol group of was targeted to generate 12 ether analogues in low-to-excellent yields, and the new library was fully characterized by NMR, UV, and MS analyses.

Cyclotheonellazoles D-I, Potent Elastase Inhibitory Thiazole-Containing Cyclic Peptides from sp. (2131).

Six new thiazole-containing cyclic peptides, the cyclotheonellazoles D-I (-), were isolated from the Australian marine sponge sp. (2131) with their structures assigned by comprehensive 1D and 2D NMR spectroscopic and MS spectrometric analyses, Marfey's derivatization studies, and comparison with time-dependent density functional theory (TDDFT) calculated ECD data. The Type 2 azole-homologated peptides herein comprise up to five nonproteinogenic amino acids, including the protease transition state mimic α-keto-β-amino acid residue 3-amino-4-methyl-2-oxohexanoic acid (Amoha), while - also contain a terminal hydantoin residue not previously found in cyclotheonellazoles.

Amphiphilic Polyamine α-Synuclein Aggregation Inhibitors from the Sponge .

Bioassay-guided investigation of the sponge resulted in the isolation and identification of two new amphiphilic polyamines, aaptolobamines A () and B (). Their structures were determined through analysis of NMR and MS data. MS analysis also indicated that contained a complex mixture of aaptolobamine homologues.

Using UHPLC-MS profiling for the discovery of new sponge-derived metabolites and anthelmintic screening of the NatureBank bromotyrosine library.

In order to further expand the NatureBank open access compound library, chemical investigations of the Australian marine sponge, were undertaken since UHPLC-MS analysis of the extract from this sponge indicated the presence of a new alkaloid. Large-scale extraction and mass-directed isolation studies on the CHCl/MeOH extract resulted in the purification of a new bromotyrosine-derived alkaloid, 5-debromopurealidin H (), along with the known marine natural product, ianthesine E (). The chemical structure of the new compound was determined following detailed spectroscopic and spectrometric data analysis.

Identification of Anthelmintic Bishomoscalarane Sesterterpenes from the Australian Marine Sponge and Structure Revision of Phyllolactones A-D.

High-throughput screening of the NatureBank marine extract library (7616 samples) identified an extract derived from the Australian marine sponge with activity against (barber's pole worm), an economically important parasitic nematode. Bioassay-guided fractionation of the CHCl/MeOH extract from led to the purification of four known bishomoscalarane sesterterpenes, phyllolactones A-D (-). The absolute configurations of phyllolactones B () and C () were determined by single-crystal X-ray diffraction analysis; literature and data analyses revealed the need for these chemical structures to be revised.

α-Synuclein binding activity of the plant growth promoter asterubine.

Preventing the aggregation of certain amyloid proteins has the potential to slow down the progression of diseases like Alzheimer's, Parkinson's, and type 2 diabetes mellitus. During a high-throughput screen of 300 Australian marine invertebrate extracts, the extract of the marine sponge Thorectandra sp. 4408 displayed binding activity to the Parkinson's disease-associated protein, α-synuclein.

Dysidenin from the Marine Sponge sp. Affects the Motility and Morphology of Larvae In Vitro.

High-throughput screening of the NatureBank marine extract library ( = 7616) using a phenotypic assay for the parasitic nematode identified an active extract derived from the Australian marine sponge sp. Bioassay-guided fractionation of the CHCl/MeOH extract from sp. resulted in the purification of two known hexachlorinated peptides, dysidenin () and dysideathiazole ().

Anti-prion and α-Synuclein Aggregation Inhibitory Sterols from the Sponge cf. .

In a study aimed at identifying new anti-prion compounds we screened a library of 500 Australian marine invertebrate derived extracts using a yeast-based anti-prion assay. This resulted in an extract from the subtropical sponge cf. showing potent anti-prion activity.

Comatulins A-E, Taurine-Conjugated Anthraquinones from the Australian Crinoid .

Chemical investigations of two specimens of the Australian crinoid afforded five new taurine-conjugated anthraquinones, comatulins A-E (-), together with 11 known marine natural products (-). The chemical structures of all the compounds were elucidated by detailed spectroscopic and spectrometric data analysis. The first X-ray crystal structure of a crinoid-derived acyl anthraquinone, rhodocomatulin 5,7-dimethyl ether (), is reported here.

Identification of Fromiamycalin and Halaminol A from Australian Marine Sponge Extracts with Anthelmintic Activity against .

There is an urgent need to discover and develop new anthelmintics for the treatment of parasitic nematodes of veterinary importance to circumvent challenges linked to drug resistant parasites. Being one of the most diverse natural ecosystems, the marine environment represents a rich resource of novel chemical entities. This study investigated 2000 extracts from marine invertebrates, collected from Australian waters, for anthelmintic activity.

Capillasterin A, a Novel Pyrano[2,3-f]chromene from the Australian Crinoid .

Capillasterin A (), a novel pyrano[2,3-f]chromene, together with seven known naphthopyrones including comaparvin (), TMC-256C1 (), 6-methoxycomaparvin-5- methyl ether (), 5,8-dihydroxy-6-methoxy-2-propyl-4H-naphtho[2,3-b]pyran-4-one (), 5,8-dihydroxy-6,10-dimethoxy-2-propyl-4H-naphtho[2,3-b]pyran-4-one (), TMC-256A1 () and 6-methoxycomaparvin () were isolated from an EtOH/H₂O extract from the Australian crinoid . The structures of all the compounds were determined by detailed spectroscopic (1D/2D NMR and MS) data analysis. This is the first report of a natural product that contains the pyrano[2,3-f]chromene skeleton.

Rhodocomatulin-Type Anthraquinones from the Australian Marine Invertebrates Clathria hirsuta and Comatula rotalaria.

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.

Isolation, structure determination and cytotoxicity studies of tryptophan alkaloids from an Australian marine sponge Hyrtios sp.

Mass-guided fractionation of the MeOH extract from a specimen of the Australian marine sponge Hyrtios sp. resulted in the isolation of two new tryptophan alkaloids, 6-oxofascaplysin (2), and secofascaplysic acid (3), in addition to the known metabolites fascaplysin (1) and reticulatate (4). The structures of all molecules were determined following NMR and MS data analysis.

Two new desma-less species of Theonella Gray, 1868 (Demospongiae: Astrophorida: Theonellidae), from the Great Barrier Reef, Australia,and a re-evaluation of one species assigned previously to Dercitus Gray, 1867.

Extensive surveys of the biodiversity on the seafloor of the inter-reef regions of the Great Barrier Reef, Australia, have resulted in the collection of large numbers of sponges, many of which are likely new to science. Identification of these sponges, however, was made difficult by the absence in some specimens of key diagnostic characters, such as megascleres. We used an integrated approach to the taxonomy of these sponges, incorporating morphological examination by SEM, analysis of DNA sequence data (using the COI barcoding fragment of mtDNA) and preliminary studies of the chemistry of the sponges, to describe the new species, which were found to contain no native spicules other than acanthose microrhabds.

Trikentramides A-D, indole alkaloids from the Australian sponge Trikentrion flabelliforme.

Chemical investigations of two specimens of Trikentrion flabelliforme collected from Australian waters have resulted in the identification of four new indole alkaloids, trikentramides A-D (9-12). The planar chemical structures for 9-12 were established following analysis of 1D/2D NMR and MS data. The relative configurations for 9-12 were determined following the comparison of (1)H NMR data with data previously reported for related natural products.