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

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

Two new steroids with cytotoxicity from the marine sponge <i>Dactylospongia elegans</i> collected from the South China Sea

<p>A new steroid, (3<i>S</i>,5<i>R</i>,9<i>R</i>,10<i>S</i>,13<i>R</i>,17<i>R</i>,20<i>R</i>,24<i>S</i>,22<i>E</i>)-ergosta-6,8,22-triene-3,25-diol (<b>1</b>), and its sulfonated analogue (<b>2</b>) together with a known one, 5α,8α-epidioxy-cholest-6-en-3β-ol (<b>3</b>) were isolated from the marine sponge <i>Dactylospongia elegans</i> collected from the South China Sea. The new structures including absolute configurations were established by the HRESIMS and 1D and 2D NMR analysis coupled with the X-ray crystal analysis. Both of <b>1</b> and <b>2</b> exhibited cytotoxicity against cancer cell line MCF-7 with IC₅₀ values of 9.7 and 8.5 μM, respectively.</p

A new α-pyrone from the deep-sea actinomycete <i>Nocardiopsis dassonvillei</i> subsp. <i>dassonvillei</i> DSM 43111(T)

<p>A new α-pyrone, nocapyrone S (<b>1</b>), together with five known compounds (<b>2-6</b>), were isolated from the deep-sea actinomycete <i>Nocardiopsis dassonvillei</i> subsp. <i>dassonvillei</i> DSM 43111(T). Their structures were determined by spectroscopic analyses. The absolute configuration of <b>1</b> was established by quantum approaches. Cytotoxic activity of <b>1</b> was evaluated against K562, MCF-7, SGC7901, A375, Hela, and HepG2 cell lines.</p

Two pairs of unusual melibiose and raffinose esters from <i>Scrophularia ningpoensis</i>

<p>A pair of unusual melibiose esters (<b>1<i>α</i></b>/<b>1<i>β</i></b>) and a pair of unusual raffinose esters (<b>2<i>α</i>/2<i>β</i></b>), were isolated from <i>Scrophularia ningpoensis</i>. Structures of them were established by detailed spectroscopic analyses to be 6-<i>O</i>-(<i>E</i>)-cinnamoyl-<i>α</i>-d-galactopyranosyl-(1→6)-<i>α</i>(<i>β</i>)-d-glucopyranose (<b>1<i>α</i></b>/<b>1<i>β</i></b>) and 6-<i>O</i>-(<i>E</i>)/(<i>Z</i>)-cinnamoyl-<i>α</i>-d-galactopyranosyl-(1→6)-<i>α</i>-d-glucopyranosyl-(1→2)-<i>β</i>-d-fructofuranose (<b>2<i>α</i>/2<i>β</i></b>), respectively. All these compounds were evaluated for antifouling activity against the settlement of <i>Balanus amphitrite</i> larvae, along with the cytotoxic effect against the proliferation of HeLa cell lines.</p

A new iridoid glycoside and a new cinnamoyl glycoside from <i>Scrophularia ningpoensis</i> Hemsl

<p>A new iridoid glycoside, namely 8-<i>O</i>-(<i>threo</i>-2, 3-dihydroxyl-3-phenyl-propionoyl)-harpagide (<b>1</b>), along with a new cinnamoyl glycoside named as <i>cis</i>-sibirioside A (<b>2</b>), were isolated from <i>Scrophularia ningpoensis</i> Hemsl. Their chemical structures were completely established by spectroscopic methods and comparison with related literatures. Compound <b>1</b> exhibited moderate antifouling effect against the settlement of <i>Balanus amphitrite</i> larvae with IC₅₀ being 13.5 μg/mL and LC₅₀ > 25 μg/mL.</p

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

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

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

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