Isolation of a new butenolide from the South China Sea gorgonian coral <i>Subergorgia suberosa</i>

<div><p>Chemical investigation on the South China Sea gorgonian coral <i>Subergorgia suberosa</i> has led to the isolation of one new butenolide (5<i>R</i>)-5-(1-ethoxypropyl)-5-hydroxy-3,4-dimethylfuran-2(5<i>H</i>)-one (<b>1</b>) as a pair of inseparable epimers, along with two known butenolides (<i>S</i>)-5-hydroxy-3,4-dimethyl-5-propylfuran-2(5<i>H</i>)-one (<b>2</b>) and (<i>S</i>)-5-hydroxy-3,4-dimethyl-5-pentylfuran-2(5<i>H</i>)-one (<b>3</b>). Their structures including absolute configurations were determined unambiguously by detailed analyses of spectroscopic data and by comparison with the available literature. Compounds <b>1</b>–<b>3</b> exhibited moderate antifouling activities against the settlement of <i>Balanus amphitrite</i> larvae, whereas compound <b>4</b>, the acetyl derivative of <b>3</b>, showed no antifouling activity at the concentrations up to 25 μg/mL.</p></div

Two new diketopiperazines from the marine sponge <i>Dysidea</i> sp.

A chemical investigation on the marine sponge Dysidea sp. resulted in the isolation of a series of diketopiperazines, including two new compounds, dysidines A (1) and B (2) as well as six known ones (3–8). Their structures with absolute configurations were determined on the basis of UV, IR, HRMS, NMR and calculated ECD method. Additionally, the cytotoxic, anti-inflammatory, antibacterial and antiviral activities of 1–8 were also tested. However, none of them exhibited significant bioactivities.</p

Spongimides A and B, two new alkaloids from the marine sponge <i>Spongia</i> sp.

Two new alkaloids, spongimides A (1) and B (2), along with five known ones (3–7), were isolated from the marine sponge Spongia sp. The structures of 1 and 2 were determined by the spectroscopic methods (UV, IR, MS, and NMR) and X-ray diffraction analysis. Compounds 1, 3, and 4 were the first examples of 2,4-imidazolidinediones isolated from this genus. In addition, the cytotoxic and antibacterial activities of compounds 1 and 2 were also evaluated.</p

Aspergchromones A and B, two new polyketides from the marine sponge-associated fungus <i>Aspergillus</i> sp. SCSIO XWS03F03

<p>Two new polyketides, aspergchromones A (<b>1</b>) and B (<b>2</b>), together with five known compounds, secalonic acid D (<b>3</b>), noreugenin (<b>4</b>), (3<i>S</i>)-5-hydroxymellein (<b>5</b>), (4<i>S</i>)-6-hydroxyisosclerone (<b>6</b>), and (-)-regiolone (<b>7</b>), were isolated from the ethyl acetate extract of marine sponge-derived fungus <i>Aspergillus</i> sp. SCSIO XWS03F03. Their structures were elucidated by means of spectroscopic techniques (1D and 2D NMR, MS, UV, and IR). The absolute configurations of the new compounds were established by ECD calculations. Compound <b>3</b> showed moderate antimicrobial activity.</p

Sinulaspirolactam A, a novel aza-spirocyclic valerenane sesquiterpenoid from soft coral <i>Sinularia</i> sp.

<p>A novel valerenane sesquiterpenoid sinulaspirolactam A (<b>1</b>), together with five known compounds, was isolated from the soft coral <i>Sinularia</i> sp. Their structures were determined by spectroscopic analyses. The absolute configuration of <b>1</b> was established by ECD calculation. Compound <b>1</b> was the first example of valerenane sesquiterpenoid bearing an aza-spiro[4.5] ring moiety, the plausible biogenetic pathway of which was proposed. Cytotoxic activities of these compounds were also evaluated.</p

Oryzamides A–E, Cyclodepsipeptides from the Sponge-Derived Fungus <i>Nigrospora oryzae</i> PF18

Three new cyclohexadepsipeptides, oryzamides A–C (<b>1</b>–<b>3</b>), two isolation artifacts, oryzamides D (<b>4</b>) and E (<b>5</b>), and the known congener scopularide A (<b>6</b>), all possessing a rare 3-hydroxy-4-methyldecanoic acid (HMDA) substructure, were isolated from the mycelial extract of the sponge-derived fungus <i>Nigrospora oryzae</i> PF18. Their planar structures were elucidated by spectroscopic analysis and comparison with the literature data. The absolute configurations were determined using the advanced Marfey’s method and single-crystal X-ray diffraction analysis. Among them, oryzamides D (<b>4</b>) and E (<b>5</b>) were a pair of diastereomers at the sulfur atom of the l-methionine sulfoxide residue, which showcased the possible separation of a pair of methionine sulfoxide diastereomers. The X-ray crystal structure of scopularide A (<b>6</b>) was obtained for the first time, thereby establishing its relative and absolute configuration at C-4 of the HMDA residue. Oryzamides A–C (<b>1</b>–<b>3</b>) did not display cytotoxic, antibacterial, antiparasitic, and NF-κB inhibitory activities

A new sesquiterpene from the gorgonian coral <i>Menella</i> sp.

<p>A new sesquiterpene named menecubebane B (1) and a known analogue (2) were isolated from the gorgonian coral <i>Menella</i> sp. Their structures were elucidated by the extensive analyses of spectroscopic data and by the comparison with related literature. Cytotoxic effect against both Eca9706 and HeLa cell lines was evaluated, revealing 1 exhibited moderate cytotoxicity against the two cell lines involved with IC₅₀ values being 20.8 and 30.6 μM, respectively.</p

Hypocrol A, a new tyrosol derivative from a sponge-derived strain of the fungus <i>Hypocrea koningii</i>

<p>In continuation of our search for new antibacterial and antioxidant metabolites from sponge-derived fungi, one new tyrosol derivative, hypocrol A (<b>1</b>), together with four known congeners, trichodenol B (<b>2</b>), 4-hydroxyphenethyl acetate (<b>3</b>), 4-hydroxyphenethyl tetradecanoate (<b>4</b>) and 1-oleyltyrosol (<b>5</b>), was isolated from the strain <i>Hypocrea koningii</i> PF04. Their planar structures were unequivocally elucidated by spectroscopic methods and comparison with the literature data. All the compounds displayed weak antibacterial activities against <i>Staphylococcus aureus</i>, methicillin-resistant <i>S. aureus</i> and <i>Escherichia coli</i>, whereas compounds <b>1</b> and <b>2</b> exhibited a moderate antioxidant efficacy in the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay with IC₅₀ values of 48.5 and 97.4 μg/mL, respectively.</p