Inducing Secondary Metabolite Production by the Endophytic Fungus <i>Fusarium tricinctum</i> through Coculture with <i>Bacillus subtilis</i>

Coculturing the fungal endophyte <i>Fusarium tricinctum</i> with the bacterium <i>Bacillus subtilis</i> 168 trpC2 on solid rice medium resulted in an up to 78-fold increase in the accumulation in constitutively present secondary metabolites that included lateropyrone (<b>5</b>), cyclic depsipeptides of the enniatin type (<b>6</b>–<b>8</b>), and the lipopeptide fusaristatin A (<b>9</b>). In addition, four compounds (<b>1</b>–<b>4</b>) including (−)-citreoisocoumarin (<b>2</b>) as well as three new natural products (<b>1</b>, <b>3</b>, and <b>4</b>) were not present in discrete fungal and bacterial controls and only detected in the cocultures. The new compounds were identified as macrocarpon C (<b>1</b>), 2-(carboxymethylamino)­benzoic acid (<b>3</b>), and (−)-citreoisocoumarinol (<b>4</b>) by analysis of the 1D and 2D NMR and HRMS data. Enniatins B1 (<b>7</b>) and A1 (<b>8</b>), whose production was particularly enhanced, inhibited the growth of the cocultivated <i>B. subtilis</i> strain with minimal inhibitory concentrations (MICs) of 16 and 8 μg/mL, respectively, and were also active against <i>Staphylococcus aureus</i>, <i>Streptococcus pneumoniae</i>, and <i>Enterococcus faecalis</i> with MIC values in the range 2–8 μg/mL. In addition, lateropyrone (<b>5</b>), which was constitutively present in <i>F. tricinctum</i>, displayed good antibacterial activity against <i>B. subtilis</i>,<i> S. aureus</i>, <i>S. pneumoniae</i>, and <i>E. faecalis,</i> with MIC values ranging from 2 to 8 μg/mL. All active compounds were equally effective against a multiresistant clinical isolate of <i>S. aureus</i> and a susceptible reference strain of the same species

Cembranoids from the Soft Coral Sinularia rigida with Antifouling Activities

Chemical examination of the soft coral Sinularia rigida resulted in the isolation of 12 new cembranoids, namely, sinulariols T–Z₅ (<b>1</b>–<b>12</b>), together with a known analogue, <b>13</b>. Their structures were determined on the basis of 1D and 2D NMR (COSY, HSQC, HMBC, and NOESY) spectroscopic analyses in association with MS and IR data. Compounds <b>7</b> and <b>13</b> showed potent antifouling activity for the inhibition against the barnacle Balanus amphitrite and moderate inhibition against Bugula neritina. The primary structure–activity relationship is discussed

Rosellosides A and B, two phenyloxazole glycosides from <i>Glycyrrhiza inflata</i>-derived fungus <i>Rosellinia</i> sp. Glinf021

Two new chlorinated phenyloxazole glycosides, named rosellosides A (1) and B (2), were isolated from the endophytic fungus Rosellinia sp. Glinf021, which was derived from the medicinal plant Glycyrrhiza inflata (Leguminosae). Both compounds were rare chlorinated polyketide glycosides bearing an oxazole moiety. Their structures were elucidated by analysis of the NMR and HRESIMS data, and their absolute configurations were determined by quantum chemical ECD calculations and X-ray crystallography.</p

Trimeric Hemibastadin Congener from the Marine Sponge <i>Ianthella basta</i>

The first naturally occurring trimeric hemibastadin congener, sesquibastadin 1 (<b>1</b>), and the previously reported bastadins 3, 6, 7, 11, and 16 (<b>2</b>–<b>6</b>) were isolated from the marine sponge <i>Ianthella basta</i>, collected in Indonesia. The structure of <b>1</b> was elucidated on the basis of 1D and 2D NMR measurements and by HRMS. Among all the isolated compounds, the linear sesquibastadin 1 (<b>1</b>) and bastadin 3 (<b>2</b>) showed the strongest inhibition rates for at least 22 protein kinases (IC₅₀ = 0.1–6.5 μM), while the macrocyclic bastadins (<b>3</b>–<b>6</b>) demonstrated a strong cytotoxic potential against the murine lymphoma cell line L5178Y (IC₅₀ = 1.5–5.3 μM)

Trimeric Anthracenes from the Endophytic Fungus <i>Stemphylium globuliferum</i>

The first naturally occurring trimeric anthracene derivatives, stemphylanthranols A and B (<b>1</b> and <b>2</b>), were obtained from the endophytic fungus <i>Stemphylium globuliferum</i> that had been isolated from <i>Juncus actus</i> growing in Egypt. The structures of the new compounds were unambiguously determined by 1D and 2D NMR, and by HRMS. A hypothetical biosynthetic pathway for the new trimers is proposed

Aaptamine Derivatives from the Indonesian Sponge <i>Aaptos suberitoides</i>

Four new aaptamine derivatives (<b>1</b>–<b>4</b><b></b>) along with aaptamine (<b>5</b>) and three related compounds (<b>6</b>–<b>8</b>) were isolated from the ethanol extract of the sponge <i>Aaptos suberitoides</i> collected in Indonesia. The structures of the new compounds were unambiguously determined by one- and two-dimensional NMR and by HRESIMS measurements. Compounds <b>3</b>, <b>5</b>, and <b>6</b> showed cytotoxic activity against the murine lymphoma L5178Y cell line, with IC₅₀ values ranging from 0.9 to 8.3 μM

New Cytotoxic 1,2,4-Thiadiazole Alkaloids from the Ascidian <i>Polycarpa aurata</i>

Two new alkaloids, polycarpathiamines A and B (<b>1</b> and <b>2</b>), were isolated from the ascidian <i>Polycarpa aurata</i>. Their structures were unambiguously determined by 1D, 2D NMR, and HRESIMS measurements and further confirmed by comparison with a closely related analogue, 3-dimethylamino-5-benzoyl-1,2,4-thiadiazole (<b>4</b>), that was prepared by chemical synthesis. Compounds <b>1</b> and <b>2</b> both feature an uncommon 1,2,4-thiadiazole ring whose biosynthetic origin is proposed. Compound <b>1</b> showed significant cytotoxic activity against L5178Y murine lymphoma cells (IC₅₀ 0.41 μM)

A new proline-containing flavonol glycoside from <i>Caragana leucophloea</i> Pojark

<div><p>One new proline-containing flavonol glycoside, namely kaempferol-3-<i>O</i>-methyl-7-<i>O</i>-β-d-glucopyranosyl-8-(1-methyleneproline)-4′-<i>O</i>-β-d-glucopyranoside (<b>1</b>), together with 15 known flavonoids, 3-<i>O</i>-methylkaempferol (<b>2</b>), 3-<i>O</i>-methylquercetin (<b>3</b>), quercetin (<b>4</b>), kaempferol (<b>5</b>), apigenin (<b>6</b>), rhamnazin (<b>7</b>), astragalin (<b>8</b>), alquds (<b>9</b>), quercitrin (<b>10</b>), rutin (<b>11</b>), isoquercitrin (<b>12</b>), apigetrin (<b>13</b>), myricitrin (<b>14</b>), hesperidin (<b>15</b>) and calycosin-7-<i>O</i>-β-d-glucopyranoside (<b>16</b>) were isolated from the aerial parts of <i>Caragana leucophloea</i> Pojark. (Leguminosae). Their structures were determined on the basis of spectroscopic analyses and by comparison with literature data. Compounds <b>2</b>–<b>4</b> revealed a strong antimicrobial activity with minimum inhibitory concentration values of 12.5–150 μg/mL and median inhibitory concentration (IC₅₀) values of 7.42–76.61 μg/mL. Compounds <b>3</b>, <b>4</b>, <b>6</b>–<b>8</b>, <b>10</b>–<b>12</b> and <b>14</b> showed strong antioxidant activity. Compounds <b>2</b>–<b>7</b> exhibited moderate antinematodal activity on <i>Caenorhabditis elegans</i> with IC₅₀ values of 40.51–68.05 μg/mL.</p></div

Callyspongiolide, a Cytotoxic Macrolide from the Marine Sponge <i>Callyspongia</i> sp.

A novel macrolide, callyspongiolide, whose structure was determined by comprehensive analysis of the NMR and HRMS spectra, was isolated from the marine sponge <i>Callyspongia</i> sp. collected in Indonesia. The compound features a carbamate-substituted 14-membered macrocyclic lactone ring with a conjugated structurally unprecedented diene-ynic side chain terminating at a brominated benzene ring. Callyspongiolide showed strong cytotoxicity against human Jurkat J16 T and Ramos B lymphocytes

New Ustilaginoidins from Rice False Smut Balls Caused by Villosiclava virens and Their Phytotoxic and Cytotoxic Activities

Ustilaginoidins are a class of bis-naphtho-γ-pyrones, typically produced by Villosiclava virens, the pathogen of the rice false smut (RFS), which has been one of the most destructive rice fungal diseases. Previously, we found that ustilaginoidins identified from the culture of V. virens on rice medium were less polar than those reported from the RFS balls in general. In this study, we reinvestigated the high-performance liquid chromatography with diode array detection and high-resolution mass spectrometry (HPLC–DAD–HRMS) profile of the ethyl acetate (EtOAc) extract of the RFS balls and found several interesting peaks that correspond to new ustilaginoidins. As a result, eight new and polar congeners, named ustilaginoidins Q–T (<b>1</b>–<b>4</b>), 2,3-dihydroustilaginoidin T (<b>5</b>), and ustilaginoidins U–W (<b>6</b>–<b>8</b>), were isolated. In addition, 17 known ustilaginoidins, including ustilaginoidins K–N (<b>9</b>–<b>12</b>), ustilaginoidin P (<b>13</b>), ustilaginoidin E₁ (<b>14</b>), isochaetochromin B₂ (<b>15</b>), and ustilaginoidins A–J (<b>16</b>–<b>25</b>), were re-isolated. The structures of the new compounds were elucidated by comprehensive analysis of the spectroscopic data. Ustilaginoidins Q (<b>1</b>) and R (<b>2</b>) feature an uncommon 2-hydroxypropyl-substituted skeleton and biogenetically incorporate one more acetate unit than common ustilaginoidins. Ustilaginoidin W (<b>8</b>) is a rare formate-containing bis-naphtho-γ-pyrone. Ustilaginoidins R (<b>2</b>), U (<b>6</b>), B (<b>17</b>), and I (<b>24</b>) showed moderate inhibitory activities toward the radicle or germ elongation of rice seeds. Ustilaginoidins R (<b>2</b>), S (<b>3</b>), V (<b>7</b>), W (<b>8</b>), B (<b>17</b>), C (<b>18</b>), and H–J (<b>23</b>–<b>25</b>) were cytotoxic to the tested human cancer cell lines (HCT116, NCI-H1650, BGC823, Daoy, and HepG2), with IC₅₀ values in the range of 4.06–44.1 μM