Arenarialins A-F, Anti-inflammatory Meroterpenoids with Rearranged Skeletons from the Marine Sponge Dysidea arenaria

Six new sesquiterpene quinone/hydroquinone meroterpenoids, arenarialins A-F (1-6), were isolated from the marine sponge Dysidea arenaria collected from the South China Sea. Their chemical structures and absolute configurations were determined by HRMS and NMR data analyses coupled with DP4+ and ECD calculations. Arenarialin A (1) features an unprecedented tetracyclic 6/6/5/6 carbon skeleton, whereas arenarialins B-D (2-4) possess two rare secomeroterpene scaffolds. Arenarialins A-F showed inhibitory activity on the production of inflammatory cytokines TNF-α and IL-6 in LPS-induced RAW264.7 macrophages with arenarialin D regulating the NF-κB/MAPK signaling pathway.

Structure-Activity Relationships for the Marine Natural Product Sintokamides: Androgen Receptor N-Terminus Antagonists of Interest for Treatment of Metastatic Castration-Resistant Prostate Cancer

Synthetic analogues of the marine natural product sintokamides have been prepared in order to investigate the structure-activity relationships for the androgen receptor N-terminal domain (AR NTD) antagonist activity of the sintokamide scaffold. An in vitro LNCaP cell-based transcriptional activity assay with an androgen-driven luciferase (Luc) reporter was used to monitor the potency of analogues. The data have shown that the chlorine atoms on the leucine side chains are essential for potent activity. Analogues missing the nonchlorinated methyl groups of the leucine side chains (C-1 and C-17) are just as active and in some cases more active than the natural products. Analogues with the natural R configuration at C-10 and the unnatural R configuration at C-4 are most potent. Replacing the natural propionamide N-terminus cap with the more sterically hindered pivaloylamide N-terminus cap leads to enhanced potency. The tetramic acid fragment and the methyl ether on the tetramic acid fragment are essential for activity. The SAR optimized analogue 76 is more selective, easier to synthesize, more potent, and presumed to be more resistant to proteolysis than the natural sintokamides.

Dysidealactams and Dysidealactones: Sesquiterpene Glycinyl-Lactams, Imides, and Lactones from a Dysidea sp. Marine Sponge Collected in Southern Australia

A GNPS molecular networking approach mapped a library of 960 southern Australian marine sponges and prioritized Dysidea sp. (CMB-01171) for chemical investigation. Although the published natural products literature on Australian Dysidea sponges extends back over half a century and suffers from the perception of being near exhausted, fractionation of Dysidea sp. (CMB-01171) led to the discovery of a family of 10 new biosynthetically and chemically related sesquiterpenes. Detailed spectroscopic analysis guided structure elucidation identified dysidealactams A-F (1-6), dysidealactones A and B (7 and 8), and two solvolysis artifacts, 9 and 10. The dysidealactams A-D (1-4) incorporate a rare glycinyl-lactam functionality, while dysidealactam E (5) is particularly noteworthy in incorporating an unprecedented glycinyl-imide moiety. In addition to expanding knowledge of Dysidea natural products, this study demonstrates the value of applying GNPS molecular networking to map chemical diversity and prioritize the selection of marine sponge extracts for more detailed chemical analysis.

Bishomoscalarane Sesterterpenoids from the Sponge Dysidea granulosa Collected in the South China Sea

Granulosane A (1), a new C₂₇ bishomoscalarane sesterterpenoid with a rare 6/6/6/8 tetracyclic skeleton, together with eight additional new C₂₇ bishomoscalarane sesterterpenes (2, 8-14) and five new C₂₆ 20,24-bishomo-25-norscalarane sesterterpenes (3-7), were isolated from the marine sponge Dysidea granulosa collected in the South China Sea. Their structures were elucidated by extensive spectroscopic analysis and quantum chemical calculation methods. Compound 4 showed antiproliferative activities against two cancer cell lines.

Sponge-derived polybrominated diphenyl ethers and dibenzo-p-dioxins, irreversible inhibitors of the bacterial α-d-galactosidase

An integrated in vitro and in silico approach was applied to evaluate the potency of hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and spongiadioxins (OH-PBDDs) isolated from Dysidea sponges on the activity of the recombinant α-d-galactosidase of the GH36 family. It was revealed for the first time that all compounds rapidly and apparently irreversibly inhibited the bacterial α-d-galactosidase. The structure-activity relationship study in the series of OH-PBDEs showed that the presence of an additional hydroxyl group in 5 significantly enhanced the potency (IC50 4.26 μM); the increase of bromination in compounds from 1 to 3 increased their potency (IC50 41.8, 36.0, and 16.0 μM, respectively); the presence of a methoxy group decreased the potency (4, IC50 60.5 μM). Spongiadioxins 6, 7, and 8 (IC50 16.6, 33.1, and 28.6 μM, respectively) exhibited inhibitory action comparable to that of monohydroxylated diphenyl ethers 1-3. Docking analysis revealed that all compounds bind in a pocket close to the catalytic amino acid residues. Molecular docking detected significant compound-enzyme interactions in the binding sites of α-d-galactosidase. Superimposition of the enzyme-substrate and the enzyme-inhibitor complexes showed that their binding sites overlap.

Selective Cytotoxicity of α-Santonin from the Persian Gulf Sponge Dysidea Avara on Pediatric ALL B-lymphocytes via Mitochondrial Targeting

Background: Acute lymphoblastic leukemia (ALL) is one of the most dominant malignancies among children, characterized by production of immature and dysfunctional blasts which are resistant to cytotoxic chemotherapeutic agents. Therefore, research protocols are currently focusing on discovery of novel anti-cancer agents to enhance survival rates and decrease unwanted side effects. Approximately two-thirds of the planet is covered by oceans with a massive range of marine organisms of interest to scientists in pharmaceutical fields. Methods: Among marine resources, sponges are known to have beneficial effects in the treatment of numerous malignancies. One fraction of crude extracts containing α-Santonin was made from the Persian Gulf marine sponge, Dysidea avara, and investigated for anticancer effects. Results: Treatment of ALL B-lymphocytes with the Dysidea avara extract caused augmentation in ROS generation, decline in mitochondrial membrane potential, mitochondrial swelling, release of cytochrome c from mitochondria and activation of caspase-3 only in mitochondria isolated from B-ALL lymphocytes. Conclusion: In brief, our results suggest that Dysidea avara extracts may selectively induce apoptosis in malignant pediatric lymphocytes.

Meroterpenoids with Protein Tyrosine Phosphatase 1B Inhibitory Activity from a Hyrtios sp. Marine Sponge

Three new meroterpenoids, hyrtiolacton A (1), nakijinol F (2), and nakijinol G (3), along with three known ones, nakijinol B (4), nakijinol E (5), and dactyloquinone A (6), were isolated and characterized from a Hyrtios sp. marine sponge collected from the South China Sea. The new structures were determined based on extensive analysis of HRESIMS and NMR data, and their absolute configurations were assigned by a combination of single-crystal X-ray diffraction and electronic circular dichroism analyses. Hyrtiolacton A (1) represents an unprecedented meroterpenoid featuring an unusual 2-pyrone attached to the sesquiterpene core, which is the first example of a pyrone-containing 4,9-friedodrimane-type sesquiterpene. These compounds were evaluated for their protein tyrosine phosphatase (PTP1B) inhibitory and cytotoxic activities. Nakijinol G (3) showed PTP1B inhibitory activity with an IC₅₀ value of 4.8 μM but no cytotoxicity against four human cancer cell lines.

Polybrominated Diphenyl Ethers: Structure Determination and Trends in Antibacterial Activity

Antibacterial-guided fractionation of the Dictyoceratid sponges Lamellodysidea sp. and two samples of Dysidea granulosa yielded 14 polybrominated, diphenyl ethers including one new methoxy-containing compound (8). Their structures were elucidated by interpretation of spectroscopic data of the natural product and their methoxy derivatives. Most of the compounds showed strong antimicrobial activity with low- to sub-microgram mL(-1) minimum inhibitory concentrations against drug-susceptible and drug-resistant strains of Staphylococcus aureus and Enterococcus faecium, and two compounds inhibited Escherichia coli in a structure-dependent manner.

Sesquiterpene Hydroquinones with Protein Tyrosine Phosphatase 1B Inhibitory Activities from a Dysidea sp. Marine Sponge Collected in Okinawa

Three new sesquiterpene hydroquinones, avapyran (1), 17-O-acetylavarol (2), and 17-O-acetylneoavarol (3), were isolated from a Dysidea sp. marine sponge collected in Okinawa together with five known congeners: avarol (4), neoavarol (5), 20-O-acetylavarol (6), 20-O-acetylneoavarol (7), and 3'-aminoavarone (8). The structures of 1-3 were assigned on the basis of their spectroscopic data. Compounds 1-3 inhibited the activity of protein tyrosine phosphatase 1B with IC50 values of 11, 9.5, and 6.5 μM, respectively, while known compounds 4-8 gave IC50 values of 12, >32, 10, 8.6, and 18 μM, respectively. In a preliminary investigation on structure-activity relationships, six ester and methoxy derivatives (9-14) were prepared from 4 and 5.

Bis-sesquiterpene from the Marine Sponge Dysidea fragilis

Two new sesquiterpenes and one new bis-sesquiterpene, named dysinidins C-E (1-3) along with three known sterols, dysideasterol F, 9α,l lα-epoxycholest-7-en-3β,5α,6α-triol, and 9α,11α-epoxycholest-7-en-3β,5α,6α,19-tetrol 6-acetate (4-6) were isolated from the Vietnamese marine sponge Dysidea fragilis (Montagu, 1814). Their structures were determined by 1D- and 2D-NMR spectroscopies and HR-ESI-MS, as well as by comparison with reported literature data. Compounds 4-6 were found to inhibit eight human cancer cell lines (KB, LU-1, HL-60, LNCaP, SK-Mel-2, HepG-2, MCF-7, and PC-3), with IC50 values ranging from 7.3 to 31.5 µM.

Dysiherbols A-C and Dysideanone E, Cytotoxic and NF-κB Inhibitory Tetracyclic Meroterpenes from a Dysidea sp. Marine Sponge

Four new tetracyclic meroterpnes, dysiherbols A-C (1-3) and dysideanone E (4), were isolated from a Dysidea sp. marine sponge collected from the South China Sea. Their complete structures and absolute configurations were unambiguously determined by a combination of NMR spectroscopic data, ECD calculations, and single-crystal X-ray diffraction analysis. Within the sesquiterpene quinol structures, dysiherbols A-C possess an intriguing 6/6/5/6-fused tetracyclic carbon skeleton. The NF-κB inhibitory and cytotoxic activity evaluation disclosed that dysiherbol A (1) showed potent activity with respective IC50 values of 0.49 and 0.58 μM, which were about 10-fold and 20-fold more potent than those of dysiherbols B (2) and C (3), which feature hydroxy and ketone carbonyl groups at the C-3 position.

Meroterpenoids from a Tropical Dysidea sp. Sponge

Six new meroterpenoids (1-6), along with arenarol (7), a known rearranged drimane sesquiterpene hydroquinone, were isolated from a Dysidea sp. sponge collected from the Federated States of Micronesia. On the basis of the results of combined spectroscopic analysis, compound 1 was determined to be the cyclic ether derivative of 7, whereas 2 and 3 were assigned as the corresponding sesquiterpene quinones containing taurine-derived substituents. Compounds 4-6 possess a novel tetracyclic skeleton formed by a direct linkage between the quinone and sesquiterpene moieties. The configurations of these new compounds were assigned on the basis of combined NOESY and ECD analysis. These compounds exhibited cytotoxic and antimicrobial activities and weak inhibition against Na(+)/K(+)-ATPase.

Sesquiterpenes from the Vietnamese Marine Sponge Dysidea fragilis

Two new sesquiterpenes, named dysinidins A-B (3, 4) along with two known sesquiterpenes, furodysinin lactone (1) and O-methyl urodysinin lactone (2), were isolated from the Vietnamese marine sponge Dysidea fragilis. Their structures were determined by ID- and 2D-NMR spectroscopies and HR ESI MS, as well as by comparison with reported literature data. None of compounds showed inhibitory growth of human lung cancer cell lines, A-549 and H-1975 (IC50 > 30 μM).

Avarol induces apoptosis in pancreatic ductal adenocarcinoma cells by activating PERK-eIF2α-CHOP signaling

Avarol is a sesquiterpenoid hydroquinone with potent cytotoxicity. Although resolving endoplasmic reticulum (ER) stress is essential for intracellular homeostasis, erratic or excessive ER stress can lead to apoptosis. Here, we reported that avarol selectively induces cell death in pancreatic ductal adenocarcinomas (PDAC), which are difficult to treat owing to the availability of few chemotherapeutic agents. Analyses of the molecular mechanisms of avarol-induced apoptosis indicated upregulation of ER stress marker BiP and ER stress-dependent apoptosis inducer CHOP in PDAC cells but not in normal cells, suggesting that avarol selectively induces ER stress responses. We also showed that avarol activated the PERK–eIF2α pathway but did not affect the IRE1 and ATF6 pathways. Moreover, CHOP downregulation was significantly suppressed by avarol-induced apoptosis. Thus, the PERK–eIF2α–CHOP signaling pathway may be a novel molecular mechanism of avarol-induced apoptosis. The present data indicate that avarol has potential as a chemotherapeutic agent for PDAC and induces apoptosis by activating the PERK–eIF2α pathway.

Dysideanones A-C, unusual sesquiterpene quinones from the South China Sea sponge Dysidea avara

Dysideanones A-C (1-3), three unusual sesquiterpene quinones with unprecedented carbon skeletons, were isolated from the South China Sea sponge Dysidea avara. Their structures including absolute configurations were determined by a combination of spectroscopic analyses and calculated ECD spectra. Within the sesquiterpene quinone structures, dysideanones A (1) and B (2) share an unprecedented 6/6/6/6-fused tetracyclic carbon skeleton, while dysideanone C (3) possesses an unusual 6/6/5/6-fused tetracyclic core. Dysideanone B (2) showed cytotoxicity against two human cancer cell lines, HeLa and HepG2, with IC50 values of 7.1 and 9.4 μM, respectively.

Muurolane-type sesquiterpenes from marine sponge Dysidea cinerea

Seven new muurolane-type sesquiterpenes, (4R,5R)-muurol-1(6),10(14)-diene-4,5-diol (1), (4R,5R)-muurol-1(6)-ene-4,5-diol (2), (4R,5R,10R)-10-methoxymuurol-1(6)-ene-4,5-diol (3), (4S)-4-hydroxy-1,10-seco-muurol-5-ene-1,10-dione (4), (4R)-4-hydroxy-1,10-seco-muurol-5-ene-1,10-dione (5), (6S,10S)-6,10-dihydroxy-7,8-seco-2,8-cyclo-muurol-4(5),7(11)-diene-12-oic acid (6), and (6R,10S)-6,10-dihydroxy-7,8-seco-2,8-cyclo-muurol-4(5),7(11)-diene-12-oic acid (7) were isolated from the marine sponge Dysidea cinerea. Their structures were determined by the combination of spectroscopic and chemical methods, including 1D-NMR, 2D-NMR, and CD spectra as well as by comparing the NMR data with those reported in the literature.

New butenolide and pentenolide from Dysidea cinerea

Two new butenolide and pentenolide derivatives, dysideolides A-B, were isolated from the marine sponge Dysidea cinerea. Their structures were determined by the combination of spectroscopic and chemical methods, including 1D- and 2D-NMR spectroscopy, and CD spectra, as well as by comparing with the NMR data reported in the literature.

Two new compounds from an Indonesian sponge Dysidea sp

On our joint bioprospecting research on Indonesian marine invertebrates, we found moderate cytotoxicity on an extract of the sponge Dysidea sp. collected at Biak, West Papua. Separation of the extract provided two new compounds, biaketide (1) and debromoantazirine (2), along with four known molecules 3-6. The new structures were elucidated by spectroscopic analyses and by comparison with those reported. Compounds 1 and 2 showed moderate cytotoxicity against NBT-T2 cells with IC50 values of 8.3 and 4.7 μg ml(- 1), respectively.

A new bioactive sesquiterpenoid quinone from the Mediterranean Sea marine sponge Dysidea avara

Investigation of the marine sponge Dysidea avara, family Dysideidae, afforded a new sesquiterpene (-)-N-methylmelemeleone-A (5), in addition to four known sesquiterpenes (+)-avarol (1), (+)-avarone (2), (-)-3'-methylaminoavarone (3) and (-)-4'-methylaminoavarone (4). The structure elucidation of compound 5 was based on 1D and 2D NMR spectroscopic, and HR-MS studies, as well as by comparison with the literature. Cytotoxicity, proteinkinase inhibition, inhibition of NFkB-activity and insecticidal activity were evaluated for the isolated compounds.

Sesquiterpenoid aminoquinones from the marine sponge Dysidea sp

Four new sesquiterpenoid arenarone derivatives, 18-aminoarenarone (1), 19-aminoarenarone (2), 18-methylaminoarenarone (3), and 19-methylaminoarenarone (4), and the new dimeric popolohuanone F (5), a derivative of 19-aminoarenarone (2) and arenarol (6), have been isolated from the Australian marine sponge Dysidea sp. together with the known compounds arenarol (6) and popolohuanone A (7). The structures of the new compounds 1-5 were established from extensive NMR spectroscopic data. Popolohuanones A (7) and F (5) and arenarol (6) showed DPPH radical scavenging activity with IC(50) values of 35, 35, and 19 microM, respectively.

Pyrodysinoic acid derivatives from the marine sponge Dysidea robusta

Three new nitrogen-containing terpenes related to pyrodysinoic acid (1) have been isolated from the sponge Dysidea robusta collected in Brazil. Isopyrodysinoic acid (2), 13-hydroxyisopyrodysinoic acid (3), and pyrodysinoic acid B (4) were obtained from the crude extract of D. robusta and identified by analysis of spectroscopic data. Pyrodysinoic acid B (4) is the first furodysin or furodysinin sesquiterpene derivative with a trans junction between the two six-membered rings of the 1,2,3,4,4a,7,8,8a-octahydro-1,1,6-trimethylnaphthalene moiety.

Saturated ceramides from the sponge Dysidea robusta

Chemical investigation of the crude extract of a marine sponge Dysidea robusta led to the isolation of an inseparable mixture of saturated ceramides. These were identified from spectroscopic data as well as by hydrolysis followed by LC-MS analysis of the sphingosine moieties.

NMR strategy for unraveling structures of bioactive sponge-derived oxy-polyhalogenated diphenyl ethers

The overexpression of the Mcl-1 protein in cancerous cells results in the sequestering of Bak, a key component in the regulation of normal cell apoptosis. Our investigation of the ability of marine-derived small-molecule natural products to inhibit this protein-protein interaction led to the isolation of several bioactive oxy-polyhalogenated diphenyl ethers. A semipure extract, previously obtained from Dysidea (Lamellodysidea) herbacea and preserved in our repository, along with an untouched Dysidea granulosa marine sponge afforded 13 distinct oxy-polyhalogenated diphenyl ethers. Among these isolates were four new compounds, 5, 6, 10, and 12. The structure elucidation of these molecules was complicated by the plethora of structural variants that exist in the literature. During dereplication, we established a systematic method for analyzing this class of compounds. The strategy is governed by trends in the (1)H and (13)C NMR shifts of the aromatic rings, and the success of the strategy was checked by X-ray crystal structure analysis.

A sesquiterpene quinone, dysidine, from the sponge Dysidea villosa, activates the insulin pathway through inhibition of PTPases

AIM

The sesquiterpene hydroquinones/quinones belong to one class of marine sponge metabolites, and they have received considerable attention due to their varied biological activities, including anti-tumor, anti-HIV, and anti-inflammatory action. In order to probe the potential anti-diabetic effect of the sesquiterpene hydroquinones/quinones, the effect of dysidine on the insulin pathway was studied.

METHODS

The promotion of glucose uptake by dysidine was studied in differentiated 3T3-L1 cells. The increase in membrane-located GLUT4 by dysidine was studied in CHO-K1/GLUT4 and 3T3-L1 cells by immuno-staining. The activation of the insulin signaling pathway by dysidine was probed by Western blotting. The inhibition of PTPases by dysidine was detected in vitro.

RESULTS

Dysidine, found in the Hainan sponge Dysidea villosa in the Chinese South Sea, effectively activated the insulin signaling pathway, greatly promoted glucose uptake in 3T3-L1 cells, and showed strong insulin-sensitizing activities. The potential targets of action for dysidine were probed, and the results indicated that dysidine exhibited its cellular effects through activation of the insulin pathway, possibly through the inhibition of protein tyrosine phosphatases, with more specific inhibition against protein tyrosine phosphatase 1B (PTP1B).

CONCLUSION

Our findings are expected to expand understanding of the biological activities of sesquiterpene hydroquinones/quinones, and they show that dysidine could be a potential lead compound in the development of an alternative adjuvant in insulin therapy.

Synthesis and biological activities of thio-avarol derivatives

Eleven new thio-avarol derivatives (3-13) were synthesized. Their antimicrobial, brine shrimp lethality, and free-radical scavenging activities and acetylcholinesterase inhibition, together with 12 already reported semisynthetic thio-avarol derivatives (14-25), were evaluated. Structure-activity relationships among these thio derivatives were determined.

A new sesquiterpenoid hydroquinone from the marine sponge Dysidea arenaria

Detailed chemical investigation of the South China sponge Dysidea arenaria resulted in the isolation of a new sesquiterpenoid hydroquinone, 19-hydroxy-polyfibrospongol B (1), along with five known compounds: polyfibrospongol B (2), isosemnonorthoquinone (3), ilimaquinone (4), smenospongine (5) and smenotronic acid (6). The structures were determined by extensive spectroscopic analysis. The in vitro anti-HIV activity on HIV-1 RT was evaluated. Compounds 3-6 displayed moderate inhibitory activity, with IC₅₀ values of 239.7, 16.4, 176.1, and 130.4 µM, respectively, while 1 and 2 were found to be inactive against the same biological target.

Bioactive polybrominated diphenyl ethers from the marine sponge Dysidea sp

A new polybrominated diphenyl ether ( 9), together with eight known compounds, were isolated from the crude organic extract of the marine sponge Dysidea sp. collected from the Federated States of Micronesia. Their structures were elucidated on the basis of various NMR spectroscopic data. These compounds exhibited inhibitory activities against Streptomyces 85E in the hyphae formation inhibition (HFI) assay and displayed antiproliferative activities against the human breast adenocarcinoma cancer cell line MCF-7. Compound 6 was selected for further evaluation in a cell cycle progression study.

Avinosol, a meroterpenoid-nucleoside conjugate with antiinvasion activity isolated from the marine sponge Dysidea sp

[structure: see text] The new meroterpenoids avinosol (1), 3'-aminoavarone (2), and 3'-phenethylaminoavarone (3) have been isolated from the marine sponge Dysidea sp. collected in Papua New Guinea, and their structures were elucidated by analysis of spectroscopic data. Avinosol (1), which is apparently the first example of a naturally occurring meroterpenoid-nucleoside conjugate, showed antiinvasion activity in a cell-based assay.

Avinosol, a meroterpenoid-nucleoside conjugate with antiinvasion activity isolated from the marine sponge Dysidea sp

[structure: see text] The new meroterpenoids avinosol (1), 3'-aminoavarone (2), and 3'-phenethylaminoavarone (3) have been isolated from the marine sponge Dysidea sp. collected in Papua New Guinea, and their structures were elucidated by analysis of spectroscopic data. Avinosol (1), which is apparently the first example of a naturally occurring meroterpenoid-nucleoside conjugate, showed antiinvasion activity in a cell-based assay.

Identification of avarol derivatives as potential antipsoriatic drugs using an in vitro model for keratinocyte growth and differentiation

Avarol, a marine sesquiterpenoid hydroquinone, and 14 avarol derivatives have shown interesting anti-inflammatory properties in previous studies. In this study, avarol and derivatives were evaluated in high-throughput keratinocyte culture models using cytokeratin 10 and SKALP/Elafin expression as markers for respectively normal and psoriatic differentiation. Avarol and five of its derivatives (5, 10, 13, 14 and 15) were selected for further study. Only 10, 13, 14 and 15 were able to inhibit keratinocyte cell growth. Changes in expression levels of 22 genes were assessed by quantitative real time PCR (qPCR). From these genes, TNFalpha mRNA levels showed the strongest changes. For compound 13, 15 and dithranol (used as a model antipsoriatic drug), a dose-dependent downregulation of TNFalpha mRNA was found. The changes in TNFalpha mRNA were confirmed at the protein level for compound 13. Additionally, this compound was able to reduce also IL-8 and COX-2 mRNA levels and this effect was correlated with a reduction in COX-2 protein expression. The mechanism of action of this compound involves at least the inhibition of NF-kappaB-DNA binding activity. In conclusion, our high-throughput screening models in combination with quantitative assessment of changes in gene expression profiles identified the avarol derivative 13, a benzylamine derivative of avarol at the 4' position of benzoquinone ring, as an interesting anti-psoriatic drug candidate that inhibits keratinocyte cell growth and TNFalpha and COX-2 expression.

Synthesis of 15,20-triamide analogue with polar substituent on the phenyl ring of arenastatin A, an extremely potent cytotoxic spongean depsipeptide

In order to increase metabolic stability and water solubility of arenastatin A, an extremely potent cytotoxic depsipeptide from the Okinawan marine sponge of Dysidea arenaria, several 15,20-triamide analogues with a polar substituent on the phenyl ring were synthesized. The 15,20-triamide analogues with a polar substituent (24, 30, and 31) showed increased solubility to MeOH and stronger cytotoxicity against KB cells in comparison with the parental 15,20-triamide analogue (2). Furthermore, the diethylamine analogue (30) exhibited in vivo anti-tumor activity against subcutaneously implanted murine sarcoma.

Haterumadysins A-D, sesquiterpenes from the Okinawan marine sponge Dysidea chlorea

Haterumadysins A-D (1-4) and two known compounds, spirodysin (5) and dehydroherbadysinolide (6), were isolated from the sponge Dysidea chlorea. Their structures were successfully determined by detailed spectroscopic analysis. Compounds 1-5 all showed the ability to inhibit the division of fertilized sea urchin eggs.

Chemical defenses of cryptic and aposematic Gastropterid molluscs feeding on their host sponge Dysidea granulosa

Numerous opisthobranchs are known to sequester chemical defenses from their prey and use them for their own defense. Information on feeding biology is critical for understanding the ecology and evolution of molluscs, yet information on feeding biology is still scarce for many groups. Gastropterid molluscs are often found on sponges, but there is controversy as to whether they are true sponge feeders. On Guam, we found the gastropterids Sagaminopteron nigropunctatum and S. psychedelicum on the sponge Dysidea granulosa. They seem to rely on contrasting defense strategies as S. psychedelicum has vivid colors, consistent with the warning coloration found in many chemically defended opisthobranchs, whereas S. nigropunctatum is highly cryptic on the sponge. S. nigropunctatum is avoided by the pufferfish Canthigaster solandri in aquarium assays. We analyzed the secondary metabolites of the two species and found that both share polybrominated diphenyl ethers (BDEs) with their host sponge D. granulosa. S. psychedelicum and S. nigropunctatum sequester the major BDE in the sponge and accumulate it in the mantle at approximately the same concentration as in the sponge (4.03 and 2.37%, respectively), and concentrate it in their parapodia at over twice the sponge concentration (7.97 and 10.10%, respectively). We also detected trace amounts in the mucus secretion of S. psychedelicum, and quantified significant amounts in the mucus (1.84%) and egg masses (2.22%) of S. nigropunctatum. Despite contrasting color patterns displayed by the two gastropterid species, they seem to share a similar chemical defense strategy, i.e., they feed on D. granulosa and accumulate the major BDE of the sponge in their tissues.

A Highly Stereocontrolled Total Synthesis of (−)-Neodysiherbaine A

Neodysiherbaine A, a neuroexitotoxin occurring in a Micronesian marine sponge Dysidea herbacea, was synthesized from tri-O-acetyl-D-glucal with excellent stereocontrol. The method established enables us to obtain gram quantities of neodysiherbaine A and its related compounds.

9-Hydroxyfurodysinin-O-ethyl lactone: a new sesquiterpene isolated from the tropical marine sponge Dysidea arenaria

A new sesquiterpene, 9-hydroxyfurodysinin-O-ethyl lactone, has been isolated from a New Caledonian Dysidea arenaria, along with three known compounds. The possible incorporation of the ethyl ether from the extraction solvent is discussed.

Anti-inflammatory sesquiterpene-quinones from the New Zealand sponge Dysidea cf. cristagalli

The inhibition of superoxide production by human neutrophils has been used to screen New Zealand's unique biota for anti-inflammatory natural products. Bioactivity-directed isolation on an extract of the sponge Dysidea cf. cristagalli led to a new sesquiterpene-quinone (4) with anti-inflammatory activity, plus acetylated hydroquinone (3). These compounds inhibited superoxide production in vitro with IC50's of 3 microM (3) and 11 microM (4).

Protection against 2,4,6-trinitrobenzenesulphonic acid-induced colonic inflammation in mice by the marine products bolinaquinone and petrosaspongiolide M

Proinflammatory mediators, namely eicosanoids, reactive oxygen and nitrogen species and cytokines, are clearly involved in the pathogenesis of intestinal bowel disease. bolinaquinone (BQ) and petrosaspongiolide M (PT), two marine products with potent anti-inflammatory action, have been shown to control the production of mediators in acute and chronic inflammatory processes. Hence, we have tested here the hypothesis that BQ and PT could ameliorate inflammation and oxidative stress parameters in 2,4,6-trinitrobenzenesulphonic acid (TNBS)-induced colitis in Balb/c mice. BQ and PT were given orally in doses of 10 or 20mg/kg/day. Treatment of the animals with BQ or PT at the highest dose significantly protected against TNBS-induced inflammation, as assessed by a reduced colonic weight/length ratio and histological scoring. Neutrophilic infiltration, interleukin (IL)-1beta and prostaglandin E(2) (PGE(2)) levels, as well as cyclooxygenase-2 (COX-2) protein expression were inhibited by both compounds. Colonic nitrite and nitrate levels and protein expression of inducible nitric oxide synthase (iNOS) were also lower in the treated groups in comparison to the TNBS control. BQ and PT reduced nitrotyrosine immunodetection and colonic superoxide anion production. Neither compound inhibited the expression of the protective protein heme oxygenase-1 (HO-1), although they reduced the extension of apoptosis. Our study also indicated that PT could interfere with the translocation of p65 into the nucleus, a key step in nuclear factor-kappaB (NF-kappaB) activation. Altogether, the results suggest that BQ and PT can have potential protective actions in intestinal inflammatory diseases.

Merosesquiterpenes from two sponges of the genus Dysidea

The chemical study of two sponges of the genus Dysidea collected in the Gulf of California has led to the isolation of the new merosesquiterpenes 20-O-acetyl-21-hydroxy-ent-isozonarol (2), 20-O-acetylneoavarol (3), ent-yahazunol (4), and dysienone (5), together with the known compounds 1 and 6-9. The structures of the new metabolites have been established by spectroscopic techniques. The absolute configuration of compounds 5 and 6 has been investigated by application of a procedure developed by Riguera et al. Compounds 2 and 5 showed cytotoxic activity against three human tumor cell lines.

Diastereoselective syntheses of deoxydysibetaine, dysibetaine, and its 4-epimer

(+/-)-Deoxydysibetaine 2 and 4-epi-dysibetaine 3 were prepared in a few steps from methyl pyroglutamate through a regioselective Mannich reaction at C-2. Natural (2S,4S)-dysibetaine 1, a sponge metabolite isolated from Dysidea herbacea, and (2S)-2 were synthesized from enantiopure (S)-pyroglutaminol with very high stereoselectivity. The key steps were an original formation of stereogenic quaternary center C-2 and the diastereoselective hydroxylation at C-4.