10 research outputs found

    Cytotoxic Diterpenoid Pseudodimers from the Korean Sponge <i>Phorbas gukhulensis</i>

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    Four new cytotoxic diterpenoid pseudodimers (<b>2</b>–<b>5</b>), along with a previously reported one, gukulenin A (<b>1</b>), were isolated from the marine sponge <i>Phorbas gukhulensis</i> collected off the coast of Gagu-do, Korea. These novel compounds, designated gukulenins C–F (<b>2</b>–<b>5</b>), were determined by extensive spectroscopic analyses to be pseudodimers of the gagunins, like gukulenin A. The termini of the tropolone-containing side chains in gukulenins C–E (<b>2</b>–<b>4</b>) were found to have diverse modifications involving acetamides or taurine, whereas gukulenin F (<b>5</b>) was formed from <b>1</b> by the ring-opening of a cyclic hemiketal. The relative and absolute configurations were assigned by Murata’s and modified Snatzke’s methods using a HETLOC experiment and a CD measurement of a dimolybdenum complex, respectively. All of these compounds exhibited significant cytotoxicity against the K562 and A549 cell lines

    Penicillipyrones A and B, Meroterpenoids from a Marine-Derived <i>Penicillium</i> sp. Fungus

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    Penicillipyrones A (<b>1</b>) and B (<b>2</b>), two novel meroterpenoids, were isolated from the marine-derived fungus <i>Penicillium</i> sp. On the basis of the results of combined spectroscopic analyses, these compounds were structurally elucidated to be sesquiterpene γ-pyrones from a new skeletal class derived from a unique linkage pattern between the drimane sesquiterpene and pyrone moieties. Compound <b>2</b> elicited significant induction of quinone reductase

    Asperphenins A and B, Lipopeptidyl Benzophenones from a Marine-Derived <i>Aspergillus</i> sp. Fungus

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    Asperphenins A (<b>1</b>) and B (<b>2</b>), novel diastereomeric lipopeptidyl benzophenone metabolites, were isolated from a marine-derived <i>Aspergillus</i> sp. fungus. On the basis of the results of combined spectroscopic analyses, the structures of these compounds were determined to be linear assemblies of three motifs: a hydroxy fatty acid, a tripeptide, and a trihydroxybenzophenone. The absolute configurations were assigned using chemical modifications and electronic circular dichroism (ECD) calculations. The novel compounds exhibited significant cytotoxicity on diverse cancer cells
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