A new 3-alkylpyridine alkaloid from the marine sponge <i>Haliclona</i> sp. and its cytotoxic activity

<p>A new alkaloid, 3-dodecyl pyridine containing a terminal cyano group (<b>1</b>), was isolated from the methanol extract of an Indonesia marine sponge <i>Haliclona</i> sp. Its chemical structure was determined by a combination of spectroscopic methods, including 1D and 2D NMR. Bioassay results indicated that compound <b>1</b> had moderate cytotoxity against tumour cell lines A549, MCF-7 and Hela with IC₅₀ values of 41.8, 48.4 and 33.2 μM, respectively.</p

Accurate mass analysis on a <10 µg sample: The actin–bound biosynthetic products were isolated from a sample (code: AC–X–A) via the procedure shown in Figure 3, Step 4.

<p>The top panel shows, by Total Ion Chromatogram (TIC) areas, three compounds of interest observed in a ratio of 37∶54∶9 from this material. The three lower panels show AM–MS data for dereplication of compounds at: 2.34 min = jasplakinolide C (<b>2</b>), 2.47 min = jasplakinolide B (<b>3</b>), and 2.85 min = jasplakinolide (<b>1</b>), respectively.</p

Deployments.

<p>Date, extract name, location, depth, time of inoculation (T_I) and time of incubation (T_C) for the 11 deployments explored in this program. Three expeditions were conducted between the period of 05/02/2011 and 07/31/2011 at three locations. Deployment 6 was lost at sea.</p

Accurate mass analysis on a <10 µg sample: The actin–bound biosynthetic products were isolated from a sample (code: AC–X–A) via the procedure shown in Figure 3, Step 4.

<p>The top panel shows, by Total Ion Chromatogram (TIC) areas, three compounds of interest observed in a ratio of 37∶54∶9 from this material. The three lower panels show AM–MS data for dereplication of compounds at: 2.34 min = jasplakinolide C (<b>2</b>), 2.47 min = jasplakinolide B (<b>3</b>), and 2.85 min = jasplakinolide (<b>1</b>), respectively.</p

<i>In Situ</i> Natural Product Discovery via an Artificial Marine Sponge

<div><p>There is continuing international interest in exploring and developing the therapeutic potential of marine–derived small molecules. Balancing the strategies for ocean based sampling of source organisms versus the potential to endanger fragile ecosystems poses a substantial challenge. In order to mitigate such environmental impacts, we have developed a deployable artificial sponge. This report provides details on its design followed by evidence that it faithfully recapitulates traditional natural product collection protocols. Retrieving this artificial sponge from a tropical ecosystem after deployment for 320 hours afforded three actin–targeting jasplakinolide depsipeptides that had been discovered two decades earlier using traditional sponge specimen collection and isolation procedures. The successful outcome achieved here could reinvigorate marine natural products research, by producing new environmentally innocuous sources of natural products and providing a means to probe the true biosynthetic origins of complex marine–derived scaffolds.</p></div

A sponge based hypothesis.

<p>A side–by–side comparison of the three natural products shown here illustrates an example of parallel biosynthetic pathways that operated in disparate organisms including marine sponges and myxobacteria. These compounds, arising from the fusion of a triketide with unusual tripeptide moieties, represent the types of biosynthetic products targeted in this study owing to their parallel biogenetic and potential microbial origins. Each compound was previously discovered from the indicated source organisms, and all were subsequently shown to be F–actin stabilizers.</p

A schematic overview.

<p>The artificial sponge was mounted underwater proximal to sponges envisioned to be engaged in secondary metabolite biosynthesis, such as shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100474#pone-0100474-g001" target="_blank">Figure 1</a>. Its components are: particle filters (disposable funnel containing a polyethylene frit, OP–6602–14, ChemGlass), microbial filters (2 µm pore, 50 mm OD, Millex–AP microbial filters, SLA05010, Millipore); a SeaBattery (DeepSea Power & Light); a power supply (self–built); a microdiaphram pump (NF5RP, KNF Neuberger); a hollow–fiber bioreactor (4300–C5011, FiberCell Systems); and parallel–bundle of sep–pak cartridges (ePlastics) containing Amberlite XAD–18 resin (Dow Chemicals). The hollow–fiber bioreactor can act as a bioreactor allowing microbial material to culture inside the artificial sponge. The sep–pak cartridges serve to collect materials either from the seawater or from the microbial content within the hollow–fiber bioreactor. Green arrows indicate flow direction during charging of the hollow–fiber bioreactor from the water column during the inoculation stage (step 1, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100474#pone-0100474-g003" target="_blank">Figure 3</a>). Blue arrows depict the passage of seawater through the artificial sponge during the incubation stage (step 2, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100474#pone-0100474-g003" target="_blank">Figure 3</a>). A generic depiction of the anatomy of a sponge is shown within the inset to illustrate the parallel engineered design, codes are: os = osculum, spc = spongocoel, chc = choanocytes, amc = amebocyte, pc = porocytes, sp = spicule, mes = mesohyl, pic = pinacocytes.</p

Final dereplication by NMR analysis: Sample AC–X–A (∼10 µg) containing the mixture shown in Figure 4 was subjected to NMR determinations at 26°C in CD₃OD using a high sensitivity 1.7 mm TCI MicroCryoProbe on a 600 MHz Avance Spectrometer (Bruker Biospin).

<p>The annotations shown for the (<b>A</b>) ¹H and (<b>B</b>) ¹H–¹H gCOSY NMR spectra confirm the dereplication assignments proposed in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100474#pone-0100474-g004" target="_blank">Figure 4</a> for jasplakinolide B (<b>3</b>) (protons coded as “b”) and jasplakinolide C (<b>2</b>) (protons coded as “c”), while resonances for jasplakinolde (<b>1</b>) could not be unambiguously observed. Ratios of <b>3</b> to <b>2</b> were estimated to be 60: 40 by peak areas shown in Figure S7 in File S1.</p

Investigation of the Physical and Bioactive Properties of Bromo- and Iodo-Containing Sponge-Derived Compounds Possessing an Oxyphenylethanamine Core

This research set out to identify compounds from marine sponges that can act as bacterial virulence blockers. Extracts from a total of 80 sponges collected from throughout Indonesia were screened in a high-throughput NF-κB-based screen that identifies compounds capable of inhibiting the bacterial type III secretion system (T3SS) in <i>Yersinia pseudotuberculosis.</i> An extract that was shown to inhibit T3SS-driven NF-κB expression was obtained from an <i>Iotrochota</i> cf. <i>iota</i> sponge and was the source of seven new bromo- and iodo-containing compounds, all of which contain a 2-(4-oxyphenyl)­ethan-1-amine core. Five were determined to be new compounds and named enisorines A–E (<b>1</b>–<b>5</b>). The remaining two were determined to be new hemibastadinol analogues named (+)-1-<i>O</i>-methylhemibastadinol 2 (<b>6</b>) and (+)-1-<i>O</i>-methylhemibastadinol 4 (<b>7</b>). All seven compounds inhibited T3SS-dependent YopE secretion and did not affect the growth or metabolic activity of <i>Y. pseudotuberculosis</i>. The most potent inhibitors of T3SS activity were enisorine C (<b>3</b>), enisorine E (<b>5</b>), and (+)-1-<i>O</i>-methylhemibastadinol 2 (<b>6</b>), all of which inhibited YopE secretion by >50% at 30 μM

Pyridinylquinazolines Selectively Inhibit Human Methionine Aminopeptidase‑1 in Cells

Methionine aminopeptidases (MetAPs), which remove the initiator methionine from nascent peptides, are essential in all organisms. While MetAP2 has been demonstrated to be a therapeutic target for inhibiting angiogenesis in mammals, MetAP1 seems to be vital for cell proliferation. Our earlier efforts identified two structural classes of human MetAP1 (<i>Hs</i>MetAP1)-selective inhibitors (<b>1</b>–<b>4</b>), but all of them failed to inhibit cellular <i>Hs</i>MetAP1. Using Mn­(II) or Zn­(II) to activate <i>Hs</i>MetAP1, we found that <b>1</b>–<b>4</b> could only effectively inhibit purified <i>Hs</i>MetAP1 in the presence of physiologically unachievable concentrations of Co­(II). In an effort to seek Co­(II)-independent inhibitors, a novel structural class containing a 2-(pyridin-2-yl)­quinazoline core has been discovered. Many compounds in this class potently and selectively inhibited <i>Hs</i>MetAP1 without Co­(II). Subsequently, we demonstrated that <b>11j</b>, an auxiliary metal-dependent inhibitor, effectively inhibited <i>Hs</i>MetAP1 in primary cells. This is the first report that an <i>Hs</i>MetAP1-selective inhibitor is effective against its target in cells