Streptocinnamides A and B, Depsipeptides from Streptomyces sp. KMM 9044

The bacterium Streptomyces sp. KMM 9044 from a sample of marine sediment collected in the northwestern part of the Sea of Japan produces highly chlorinated depsiheptapeptides streptocinnamides A (1) and B (2), representatives of a new structural group of antibiotics. The structures of 1 and 2 were determined using nuclear magnetic resonance and mass spectrometry studies and confirmed by a series of chemical transformations. Streptocinnamide A potently inhibits Micrococcus sp. KMM 1467, Arthrobacter sp. ATCC 21022, and Mycobacterium smegmatis MC2 155.

Toporosides A and B, Cyclopentenyl-Containing ω-Glycosylated Fatty Acid Amides, and Toporosides C and D from the Northwestern Pacific Marine Sponge Stelodoryx toporoki

Toporosides A-D (1-4), new ω-glycosylated fatty acid amides, were isolated from the sponge Stelodoryx toporoki. The structures of these compounds, including absolute configurations of stereogenic centers, were established using analysis of 1D and 2D NMR, ECD, and HR mass spectra as well as chemical transformations. Toporosides A (1) and B (2) are the first lipids containing a cyclopentenyl α,β-unsaturated carbonyl moiety in the polymethylene chain. Toporoside C (3) is likely a precursor, which undergoes intramolecular aldol condensation to produce 1 and 2. Toporosides A, C, and D showed protective effects against TNF-α-induced injury in H9c2 cardiomyocytes.

New Deoxyisoaustamide Derivatives from the Coral-Derived Fungus Penicillium dimorphosporum KMM 4689

Seven new deoxyisoaustamide derivatives (1-7) together with known compounds (8-10) were isolated from the coral-derived fungus Penicillium dimorphosporum KMM 4689. Their structures were established using spectroscopic methods, X-ray diffraction analysis and by comparison with related known compounds. The absolute configurations of some alkaloids were determined based on CD and NOESY data as well as biogenetic considerations. The cytotoxic and neuroprotective activities of some of the isolated compounds were examined and structure-activity relationships were pointed out. New deoxyisoaustamides 4-6 at concentration of 1 µM revealed a statistical increase of PQ(paraquat)-treated Neuro-2a cell viability by 30-39%.

Structural Analysis of Oxidized Cerebrosides from the Extract of Deep-Sea Sponge Aulosaccus sp.: Occurrence of Amide-Linked Allylically Oxygenated Fatty Acids

The structural elucidation of primary and secondary peroxidation products, formed from complex lipids, is a challenge in lipid analysis. In the present study, rare minor oxidized cerebrosides, isolated from the extract of a far eastern deep-sea glass sponge, Aulosaccus sp., were analyzed as constituents of a multi-component RP-HPLC (high-performance liquid chromatography on reversed-phase column) fraction using NMR (nuclear magnetic resonance) spectroscopy, mass spectrometry, GC (gas chromatography), and chemical transformations (including hydrogenation or derivatization with dimethyl disulfide before hydrolysis). Eighteen previously unknown β-D-glucopyranosyl-(1→1)-ceramides (1a-a//, 1b-b//, 2a-a//, 2b-b//, 3c-c//, 3d-d//) were shown to contain phytosphingosine-type backbones (2S,3S,4R,11Z)-2-aminoeicos-11-ene-1,3,4-triol (in 1), (2S,3S,4R,13Z)-2-aminoeicos-13-ene-1,3,4-triol (in 2), and (13S*,14R*)-2-amino-13,14-methylene-eicosane-1,3,4-triol (in 3). These backbones were N-acylated with straight-chain monoenoic (2R)-2-hydroxy acids that had allylic hydroperoxy/hydroxy/keto groups on C-17/ in the 15/E-23:1 chain (a-a//), C-16/ in the 17/E-23:1 (b-b//) and 14/E-22:1 (c-c//) chains, and C-15/ in the 16/E-22:1 chain (d-d//). Utilizing complementary instrumental and chemical methods allowed for the first detailed structural analysis of a complex mixture of glycosphingolipids, containing allylically oxygenated monoenoic acyl chains.

Synthesis and Evaluation of Antimicrobial and Cytotoxic Activity of Oxathiine-Fused Quinone-Thioglucoside Conjugates of Substituted 1,4-Naphthoquinones

A series of new tetracyclic oxathiine-fused quinone-thioglycoside conjugates based on biologically active 1,4-naphthoquinones and 1-mercapto derivatives of per-O-acetyl d-glucose, d-galactose, d-xylose, and l-arabinose have been synthesized, characterized, and evaluated for their cytotoxic and antimicrobial activities. Six tetracyclic conjugates bearing a hydroxyl group in naphthoquinone core showed high cytotoxic activity with EC50 values in the range of 0.3 to 0.9 μM for various types of cancer and normal cells and no hemolytic activity up to 25 μM. The antimicrobial activity of conjugates was screened against Gram-positive bacteria (Staphylococcus aureus, Bacillus cereus), Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli), and fungus Candida albicans by the agar diffusion method. The most effective juglone conjugates with d-xylose or l-arabinose moiety and hydroxyl group at C-7 position of naphthoquinone core at concentration 10 µg/well showed antimicrobial activity comparable with antibiotics vancomicin and gentamicin against Gram-positive bacteria strains. In liquid media, juglone-arabinosidic tetracycles showed highest activity with MIC 6.25 µM. Thus, a positive effect of heterocyclization with mercaptosugars on cytotoxic and antimicrobial activity for group of 1,4-naphthoquinones was shown.

Inspired by Sea Urchins: Warburg Effect Mediated Selectivity of Novel Synthetic Non-Glycoside 1,4-Naphthoquinone-6S-Glucose Conjugates in Prostate Cancer

The phenomenon of high sugar consumption by tumor cells is known as Warburg effect. It results from a high glycolysis rate, used by tumors as preferred metabolic pathway even in aerobic conditions. Targeting the Warburg effect to specifically deliver sugar conjugated cytotoxic compounds into tumor cells is a promising approach to create new selective drugs. We designed, synthesized, and analyzed a library of novel 6-S-(1,4-naphthoquinone-2-yl)-d-glucose chimera molecules (SABs)—novel sugar conjugates of 1,4-naphthoquinone analogs of the sea urchin pigments spinochromes, which have previously shown anticancer properties. A sulfur linker (thioether bond) was used to prevent potential hydrolysis by human glycoside-unspecific enzymes. The synthesized compounds exhibited a Warburg effect mediated selectivity to human prostate cancer cells (including highly drug-resistant cell lines). Mitochondria were identified as a primary cellular target of SABs. The mechanism of action included mitochondria membrane permeabilization, followed by ROS upregulation and release of cytotoxic mitochondrial proteins (AIF and cytochrome C) to the cytoplasm, which led to the consequent caspase-9 and -3 activation, PARP cleavage, and apoptosis-like cell death. These results enable us to further clinically develop these compounds for effective Warburg effect targeting.

Virescenosides From the Holothurian-Associated Fungus Acremonium Striatisporum Kmm 4401

Ten new diterpene glycosides virescenosides Z9-Z18 (1-10) together with three known analogues (11-13) and aglycon of virescenoside A (14) were isolated from the marine-derived fungus Acremonium striatisporum KMM 4401. These compounds were obtained by cultivating fungus on wort agar medium with the addition of potassium bromide. Structures of the isolated metabolites were established based on spectroscopic methods. The effects of some isolated glycosides and aglycons 15-18 on urease activity and regulation of Reactive Oxygen Species (ROS) and Nitric Oxide (NO) production in macrophages stimulated with lipopolysaccharide (LPC) were evaluated.

Guitarrins A-E and Aluminumguitarrin A: 5-Azaindoles from the Northwestern Pacific Marine Sponge Guitarra fimbriata

Guitarrins A-E (1-5), the first natural 5-azaindoles, and aluminumguitarrin A (1a), the first aluminum-containing compound from marine invertebrates, were isolated from the sponge Guitarra fimbriata. The structures of these compounds were established using detailed analysis of 1D and 2D NMR data, mass spectra, and X-ray analysis of 1 and 1a. Compound 3 was proved to be a natural inhibitor of alkaline phosphatase.

Naphto-Γ-pyrones from the marine-derived fungus Aspergillus foetidus

Nine naphto-γ-pyrones rubrofusarine B (1), TMC 256 A1 (2), fansecinones A (3) and B (4), aurasperones A (5), B (6) and F (7), dianhydro-aurasperone C (8) and asperpyrone B (9) were isolated from the marine-derived fungus Aspergillus foetidus KMM 4694. Their structures were established based on spectroscopic methods. The effect of the substances on viability and colony formation of human drug-resistant prostate cancer 22Rv1 cell was evaluated.

Melonoside B and Melonosins A and B, Lipids Containing Multifunctionalized ω-Hydroxy Fatty Acid Amides from the Far Eastern Marine Sponge Melonanchora kobjakovae

Melonoside B (1) and melonosins B (2) and A (3), new lipids based on polyoxygenated fatty acid amides, and known melonoside A (4) were isolated from two different collections of the marine sponge Melonanchora kobjakovae. The structures of these compounds, including their absolute configurations, were established using detailed analysis of 1D and 2D NMR, ECD, and mass spectra as well as chemical transformations. Melonosins 2 and 3 inhibit AP-1- and NF-kB-dependent transcriptional activities in JB6 Cl41 cells at noncytotoxic concentrations, demonstrating potential cancer preventive activity.

Absolute Configuration of the Cytotoxic Marine Alkaloid Monanchocidin A

The absolute configuration of the cytotoxic guanidine alkaloid monanchocidin A with 11 stereogenic centers from the marine sponge Monanchora pulchra was determined as 5 R, 8 S, 10 S, 13 R, 14 S, 15 R, 19 R, 23 R, 37 S, 42 S, 43 R after extensive reductive degradation and conversion of the resulting alcohols to MTPA derivatives.

Synthesis of Polyhydroxylated Aminonaphthazarins Related to Natural Pigments

Amino analogs of echinochrome and ethylmompain, metabolites of sea urchins Scaphechinus mirabilis and Echinothrix diadema, and amino analogs of cristazarin, a metabolite of lichen Cladonia cristatella, were synthesized.

Analysis of the Configuration of an Isolated Double Bond in Some Lipids by Selective Homonuclear Decoupling

The purpose of this report is to demonstrate that selective homonuclear decoupling can be used as an alternative for 13C NMR method for identifying configuration of an isolated (mid-chain) double bond in some lipids. Using homodecoupling of allylic protons, the coupling constants Jcis or Jtrans between the olefinic protons of some fatty acid methyl esters and related compounds with ( n–7) and ( n–9) terminal structures were evaluated. The optimal conditions of the homodecoupling experiments on these compounds were examined. Empirical rules were proposed to predict the results of homodecoupling experiments on lipid with an isolated double bond.

Synthesis and Cytotoxic Evaluation of Glucoconjugated Ethylmompain Derivatives

Quinone-carbohydrate conjugates of ethylmompain, a pigment of the sea urchin Echinothrix diadema, and its chlorinated analog were synthesized. The cytotoxic activity and contraceptive properties of the synthesized compounds have been investigated using the sperm and eggs of the sea urchin Strongylocentrotus intermedius.

Normonanchocidins G and H, New Pentacyclic Guanidine Alkaloids from the Far-Eastern Marine Sponge Monanchora pulchra

Two new pentacyclic guanidine alkaloids, normonanchocidins G (1) and H (2) containing an unusual ω-2-hydroxy fatty acid moiety were isolated from the Far-Eastern marine sponge Monanchora pulchra. The structures of 1 and 2 were determined by 1D- and 2D-NMR spectroscopic and mass spectrometric data interpretation. Compounds 1 and 2 exhibit potent cytotoxic activities against human leukemia THP-1, HL-60 cells, human cervical epithelioid carcinoma HeLa cells and also have high impact on ability of HeLa cells to migrate.

Synthesis and Comparative Evaluation of Polymethoxy Substituted 1,4-Naphthoquinones and their Acetyl-O-glucosides as Cytotoxic Agents

Twenty five hydroxy-, chloro- and methoxy derivatives of natural and synthetic naphthazarins and their acetylated O-glycosides were synthesized. Targeted compounds were screened as cytotoxic agents on mouse Ehrlich ascites carcinoma cells using MTT test. Chloro- and methoxy-substituted naphthoquinones as well as naphthoquinone O-acetylglucosides were the most potent with IC50 in low micromolar concentration range. Glucosidation of hydroxynaphthoquinones was shown to enhance cytotoxicity, whereas methoxylation yielded both more active and less active derivatives depending on the number and position of methoxy groups. Evaluation using a phenotypic sea urchin embryo assay suggested that naphthazarins exerted their cytotoxic effects through tubulin-unrelated mechanism.

Pallidopenillines: Polyketides from the Alga-Derived Fungus Penicillium thomii Maire KMM 4675

Eleven new polyketides, pallidopenillines 1-11, were isolated from the alga-derived fungus Penicillium thomii. The structures of these compounds were established based on spectroscopic methods. The absolute configuration of pallidopenilline A (1) as 4R, 5S, 8S, 9R, 10R, 13R was established using a combination of the modified Mosher's method, X-ray analysis, and NOESY data. The absolute configurations of 2-5 were determined by time-dependent density functional theory calculations of the ECD spectra and ECD and NOESY data. It was shown that 1-acetylpallidopenilline A (2) and pallidopenilline G (10) inhibit the growth of colonies of 22Rv1 cells by 40% at 2 and 1 μM, respectively.

Monanchoxymycalins A and B, New Hybrid Pentacyclic Guanidine Alkaloids from the Far-Eastern Marine Sponge Monanchora pulchra

The new pentacyclic guanidine alkaloids, monanchoxymycalin A (1) and monanchoxymycalin B (2) were isolated from the Far-Eastern marine sponge Monanchora pulchra. Their structures were assigned on the basis of detailed analysis of 1D- and 2D-NMR spectroscopic and mass spectrometric data. Compounds 1 and 2 exhibited potent cytotoxic activities against cervical epithelioid carcinoma HeLa cells and breast adenocarcinoma MDA-MB231 cells.

Monanchoxymycalins A and B, New Hybrid Pentacyclic Guanidine Alkaloids from the Far-Eastern Marine Sponge Monanchora pulchra

The new pentacyclic guanidine alkaloids, monanchoxymycalin A (1) and monanchoxymycalin B (2) were isolated from the Far-Eastern marine sponge Monanchora pulchra. Their structures were assigned on the basis of detailed analysis of lD- and 2D-NMR spectroscopic and mass spectrometric data. Compounds 1 and 2 exhibited potent cytotoxic activities against cervical epithelioid carcinoma HeLa cells and breast adenocarcinoma MDA-MB231 cells.

Gramine-derived Bromo-alkaloids Activating NF--kB-dependent Transcription from the Marine Hydroid Abietinaria abietina

Two new natural products, 6-bromogramine (1) and bis-6-bromogramine (2) were isolated from the marine hydroid A bietinaria abietina and their structures were established using NMR and MS analysis. Compounds 1 and 2 activate NF-cB-dependent transcriptional activity in JB6 Cl 41 NF-KB cells at 1.6 AM concentrations.

N-Demethylaaptanone, A new Congener of Aaptamine Alkaloids from the Vietnamese Marine Sponge Aaptos aaptos

A new compound, N-demethylaaptanone (5), having an oxygenated 1,6-naphthyridine core, has been isolated from the Vietnamese marine sponge Aaptos aaptos, along with the known metabolites, aaptamine (1), isoaaptamine (2), 9-demethylaaptamine (3), and aaptanone (4). The structure of N-demethylaaptanone was determined as 9-hydroxy-8-methoxy-4 H-benzo[ de][1,6]-naphthyridine-5,6-dione from spectroscopic data.

Gramine-derived Bromo-alkaloids Activating NF-κB-dependent Transcription from the Marine Hydroid Abietinaria abietina

Two new natural products, 6-bromogramine (1) and bis-6-bromogramine (2) were isolated from the marine hydroid Abietinaria abietina and their structures were established using NMR and MS analysis. Compounds 1 and 2 activate NF-κB-dependent transcriptional activity in JB6 Cl 41 NF-κB cells at 1.6 μM concentrations.

Absolute Configuration and Body Part Distribution of the Alkaloid 6-epi-Monanchorin from the Marine Polychaete Chaetopterus variopedatus

As a result of the first study on secondary metabolites from the cosmopolitan bioluminescent marine tube polychaete Chaetopterus variopedatus, a new bicyclic guanidine alkaloid, 6- epi-monanchorin (1), along with the previously known monanchorin (2) were isolated. The structure of 1 was elucidated by spectroscopic and chemical methods, including a cleavage of the C1–O7 bond to obtain a secondary alcohol (3), which was used to determine the absolute configurations by Mosher's method. It was found that 1 and 2 were mainly accumulated in a secreted mucus special organ of the worm (food net), where green and blue-green microalgae were detected. A biosynthetic pathway to 6- epi-monanchorin and monanchorin from dietary polyenic fatty acid precursors was proposed.

N-Demethylaaptanone, A new Congener of Aaptamine Alkaloids from the Vietnamese Marine Sponge Aaptos aaptos

A new compound, N-demethylaaptanone (5), having an oxygenated 1,6-naphthyridine core, has been isolated from the Vietnamese marine sponge Aaptos aaptos, along with the known metabolites, aaptamine (1), isoaaptamine (2), 9-demethylaaptamine (3), and aaptanone (4). The structure of N-demethylaaptanone was determined as 9-hydroxy-8-methoxy-4H-benzo[de][1,6]-naphthyridine-5,6-dione from spectroscopic data.

New 6,6-Spiroketal from the Alga-Derived Fungus Penicillium lividum

The new 6,6-spiroketal,sargassopenilline H (1), and known peneciraistin C (2) have been isolated from an EtOAc extract of the marine-derived fungus Penicillium lividumKMM 4663. The structure of the new metabolite was determined by HR ESIMS and 1D and 2D NMR spectroscopy. Sargassopenilline H (1) in non-cytotoxic concentration inhibited colony formation of RPMI-7951 and MDA-MB-231 cell lines.

New 6,6-Spiroketal from the Alga-Derived Fungus Penicillium Lividum

The new 6,6-spiroketal, sargassopenilline H (1), and known peneciraistin C (2) have been isolated from an EtOAc extract of the marine-derived fungus PenicilliumlividumKMM 4663. The structure of the new metabolite was determined by HR ESIMS and 1D and 2D NMR spectroscopy. Sargassopenilline H (1) in non-cytotoxic concentration inhibited colony formation of RPMI-7951 and MDA-MB-231 cell lines.

Examination of the structures of several glycerolipids from marine macroalgae by NMR and GC-MS

Several classes of glycerolipids were isolated from the total lipids of the algae Saccharina cichorioides, Eualaria fistulosa, Fucus evanescens, Sargassum pallidum, Silvetia babingtonii (Ochrophyta, Phaeophyceae), Tichocarpus crinitus, and Neorhodomela larix (Rhodophyta, Florideophyceae). The structures of these lipids were examined by nuclear magnetic resonance (NMR) spectroscopy, including 1D ((1) H and (13) C) and 2D (COSY, HSQC and HMBC) experiments. All of the investigated algae included common galactolipids and sulfonoglycolipids as the major glycolipids. Minor glycolipids isolated from S. cichorioides, T. crinitus, and N. laris were identified as lyso-galactolipids with a polar group consisted of the galactose. Comparison of the (1) H NMR data of minor nonpolar lipids isolated from the extracts of the brown algae S. pallidum and F. evanescens with the (1) H NMR data of other lipids allowed them to be identified as diacylglycerols. The structures of betaine lipids isolated from brown algae were confirmed by NMR for the first time. The fatty acid compositions of the isolated lipids were determined by gas chromatography-mass spectrometry.

Structural Analysis of the Minor Cerebrosides from a Glass Sponge Aulosaccus sp

The minor cerebrosides from a Far-Eastern glass sponge Aulosaccus sp. were analyzed as constituents of some multi-component RP-HPLC fractions. The structures of eighteen new and one known cerebrosides were elucidated on the basis of NMR spectroscopy, mass spectrometry, optical rotation data and chemical transformations. These β-D-glucopyranosyl-(1→1)-ceramides contain sphingoid bases N-acylated with straight-chain (2R)-2-hydroxy fatty acids, namely, (2S,3S,4R,11Z)-2-aminoeicos-11-ene-1,3,4-triol, acylated with 15E-22:1, 16Z-21:1, 15Z-21:1, 15Z-20:1, 15E-20:1, 19:0, 18:0 acids, (2S,3S,4R)-2-amino-13-methyltetradecane-1,3,4-triol--with 19Z-26:1, 16Z-23:1, 23:0, 22:0 acids, (2S,3S,4R)-2-amino-14-methylpentadecane-1,3,4-triol--with 16Z-23:1, 16E-23:1, 15Z-22:1, 22:0 acids, (2S,3S,4R)-2-amino-14-methylhexadecane-1,3,4-triol, linked to 16Z-23:1, 15Z-22:1 acids, (2S,3S,4R)-2-amino-9-methylhexadecane-1,3,4-triol--to 16Z-23:1 acid, and (2S,3S,4R)-2-aminohexadecane-1,3,4-triol, attached to 15Z-22:1 acid. The 13-methyl and 9-methyl-branched trihydroxy sphingoid base backbones (C15 and C17, respectively) have not been found previously in sphingolipids. The ceramide parts, containing other backbones, present new variants of N-acylation of the marine sphingoid bases with the 2-hydroxy fatty acids. The combination of the instrumental and chemical methods used in this study improved the efficiency of the structural analysis of such complex cerebroside mixtures that gave more detailed information on glycosphingolipid metabolism of the organism.

New Derivatives of Natural Acyclic Guanidine Alkaloids with TRPV Receptor-Regulating Properties

The guanidine alkaloids, dihydropulchranin A (2), prepared from pulchranin A from the sponge Monanchora pulchra, and hexadecylguanidine (3), a synthetic analog of pulchranins, were studied for their TRPV channel-regulating activities. Compound 2 was active as an inhibitor of rTRPV1 and hTRPV3 receptors with EC50 values of 24.3 and 59.1 μM, respectively. Hexadecylguanidine (3) was not active against these receptors.

Synthesis, Cytotoxic and Contraceptive Activity of 6,8,9-Trihydroxy-2-methyl-2H-naphtho[2,3-b]pyran-5,10-dione, a Pigment of Echinothrix diadema, and its Analogs

6,8,9-Trihydroxy-2-methyl-2H-naphtho[2,3-b]pyran-5,10-dion, a pigment of the sea urchin Echinothrix diadema, and six analogs were synthesized. The cytotoxic activity and contraceptive properties of the synthesized pyranonaphthazarins have been investigated using the sperm and eggs of the sea urchin Strongylocentrotus intermedius.

Synthesis, Cytotoxic and Contraceptive Activity of 6,8,9-Trihydroxy-2-methyl-2H-naphtho[2,3-b]pyran-5,10-dione, a Pigment of Echinothrix diadema, and its Analogs

6,8,9-Trihydroxy-2-methyl-2 H-naphtho[2,3- b]pyran-5,10-dion, a pigment of the sea urchin Echinothrix diadema, and six analogs were synthesized. The cytotoxic activity and contraceptive properties of the synthesized pyranonaphthazarins have been investigated using the sperm and eggs of the sea urchin Strongylocentrotus intermedius.

New Derivatives of Natural Acyclic Guanidine Alkaloids with TRPV Receptor-Regulating Properties

The guanidine alkaloids, dihydropulchranin A (2), prepared from pulchranin A from the sponge Monanchora pulchra, and hexadecylguanidine (3), a synthetic analog of pulchranins, were studied for their TRPV channel-regulating activities. Compound 2 was active as an inhibitor of rTRPV1 and hTRPV3 receptors with EC50 values of 24.3 and 59.1 μM, respectively. Hexadecylguanidine (3) was not active against these receptors.

Pyridine Nucleosides Neopetrosides A and B from a Marine Neopetrosia sp. Sponge. Synthesis of Neopetroside A and Its β-Riboside Analogue

Neopetrosides A (1) and B (2), new naturally occurring ribosides of nicotinic acid with extremely rare α-N-glycoside linkages and residues of p-hydroxybenzoic and pyrrole-2-carboxylic acids attached to C-5', were isolated from a marine Neopetrosia sp. sponge. Structures 1 and 2 were determined by NMR and MS methods and confirmed by the synthesis of 1 and its β-riboside analogue (3). Neopetroside A (1) upregulates mitochondrial functions in cardiomyocytes.

Normonanchocidins A, B and D, New Pentacyclic Guanidine Alkaloids from the Far-Eastern Marine Sponge Monanchora pulchra

New pentacyclic guanidine alkaloids, normonanchocidins A, B and D (1–3) along with the earlier known monanchocidin A were isolated from the Far-Eastern marine sponge Monanchora pulchra. Structures of 1–3 were elucidated using 1D- and 2D-NMR spectroscopic and mass spectrometric data. Compound 1 and a mixture of 2 and 3 (1:1) exhibited cytotoxic activities against human leukemia THP-1 cells with IC50 values of 2.1 μM and 3.7 μM, respectively, and against cervix epithelial carcinoma HeLa cells with IC50 of 3.8 μM and 6.8 μM, respectively.

Sargassopenillines A-G, 6,6-spiroketals from the alga-derived fungi Penicillium thomii and Penicillium lividum

Seven new 6,6-spiroketals, sargassopenillines A-G (1-7) were isolated from the alga-derived fungi Penicillium thomii KMM 4645 and Penicillium lividum KMM 4663. The structures of these metabolites were determined by HR-MS and 1D and 2D NMR. The absolute configurations of compounds 1, 5 and 6 were assigned by the modified Mosher's method and by CD data. Sargassopenilline C (3) inhibited the transcriptional activity of the oncogenic nuclear factor AP-1 with an IC50 value of 15 µM.

Total Synthesis of Hybocarpone, a Cytotoxic Naphthazarin Derivative from the Lichen Lecanora hybocarpa, and Related Compounds

The concise synthesis of the lichen-derived antitumor agent hybocarpone (1) and its analogs is described. A new synthetic approach is based on the direct oxidative dimerization of the available naphthazarin precursors in the formation of the binaphtho[2,3- b; 2,3- d]furantetraone structure. It was shown that the first step to tetrahydrofuran features is the bridging hindered S*, S* and R*, S* carbon-carbon bonds of the molecules, setting the relative configurations of the 5a S*,6a S*,12a S*,12b S* and 5a S*,6a R*,12a R*,12b S* diastereomers.

Total synthesis of hybocarpone, a cytotoxic naphthazarin derivative from the lichen Lecanora hybocarpa, and related compounds

The concise synthesis of the lichen-derived antitumor agent hybocarpone (1) and its analogs is described. A new synthetic approach is based on the direct oxidative dimerization of the available naphthazarin precursors in the formation of the binaphtho[2,3-b; 2,3-d]furantetraone structure. It was shown that the first step to tetrahydrofuran features is the bridging hindered S*,S* and R*,S* carbon-carbon bonds of the molecules, setting the relative configurations of the 5aS*,6aS*,12aS*,12bS* and 5aS*,6aR*,12aR*,12bS* diastereomers.

Meroterpenoids from the alga-derived fungi Penicillium thomii Maire and Penicillium lividum Westling

Ten new austalide meroterpenoids (1-10) were isolated from the alga-derived fungi Penicillium thomii KMM 4645 and Penicillium lividum KMM 4663. Their structures were elucidated by extensive spectroscopic analysis and by comparison with related known compounds. The absolute configurations of some of the metabolites were assigned by the modified Mosher's method and CD data. Compounds 1, 2, 8, and 9 were able to inhibit AP-1-dependent transcriptional activity in JB6 Cl41 cell lines at noncytotoxic concentrations. Austalides 1-5, 8, and 9 exhibited significant inhibitory activity against endo-1,3-β-D-glucanase from a crystalline stalk of the marine mollusk Pseudocardium sachalinensis.

Concerning the Structure of Islandoquinone Isolated from the Lichen Cetraria islandica

An investigation of the oxidative coupling products of some substituted hydroxynaphthazarins led to a revision of the proposed structure of islandoquinone, previously isolated from the lichen Cetraria islandica, and yielding (7a S*,13a S*)-6,7a-diethyl-2,5,9,11,12,13a-hexahydroxy-7,14-dioxabenzo[ a]tetracene-1,4,8,13(7a H,13a H)-tetraone through X-ray diffraction analysis of its 2,11-dimethyl ether.

Tauroarenarones A and B, New Taurine-containing Meroterpenoids from the Marine Sponge Dysidea sp

Two new taurine-containing meroterpenoids, both arenarone derivatives, tauroarenarone A (1) and tauroarenarone B (2), have been isolated from the Australian marine sponge Dysidea sp. Their structures were established from NMR spectroscopic data.

Tauroarenarones A and B, new taurine-containing meroterpenoids from the marine sponge Dysidea sp

Two new taurine-containing meroterpenoids, both arenarone derivatives, tauroarenarone A (1) and tauroarenarone B (2), have been isolated from the Australian marine sponge Dysidea sp. Their structures were established from NMR spectroscopic data.

Concerning the structure of islandoquinone isolated from the lichen Cetraria islandica

An investigation of the oxidative coupling products of some substituted hydroxynaphthazarins led to a revision of the proposed structure of islandoquinone, previously isolated from the lichen Cetraria islandica, and yielding (7aS*, 13aS*)-6,7a-diethyl-2,5,9,11,12,13a-hexahydroxy-7, 4-dioxabenzo[a]tetracene-1,4,8,13(7aH, 13aH)-tetraone through X-ray diffraction analysis of its 2,11-dimethyl ether.

Quinone-carbohydrate nonglucoside conjugates as a new type of cytotoxic agents: synthesis and determination of in vitro activity

We have found that 2-methoxy-1,4-naphthoquinones easily react with primary alcohols to produce the corresponding 2-alkoxyderivatives. Using this reaction, we synthesized methyl-6-O-(naphthalene-1,4-dione-2-yl)-α-D-glucopyranosides, a new type of water soluble quinone-carbohydrate nonglucoside conjugates. The resulting conjugates induced apoptosis in human cancer HeLa and normal mouse JB6 P(+) Cl41 cells with simultaneous inhibition of p53-dependant transcriptional activity, suggesting that the observed cell death was p53-independent. Furthermore, we analyzed structure-activity relationship and bioactivity of 2-hydroxy- and 2-methoxy-1,4-naphthoquinones as well as carbohydrate nonglucoside conjugates. All compounds containing a quinone moiety were able to inhibit p53-dependant transcriptional activity and exerted moderate inhibitory effects on HeLa cell colony formation. Investigations of structure-activity relationships revealed that cytotoxicity depended on the type of substituent at C-2 of the quinone moiety, decreasing in the following order: methoxyderivatives > carbohydrate nonglucoside conjugates > hydroxyderivatives. Furthermore, cytotoxicity depended on the position of the hydroxy substituent in the quinone moiety in all derivatives and decreased in the following order: 8- > 5- > 5,8-derivatives. In conclusion, this is the first report on synthesis and biological structure-activity relationships of the new class of quinone-carbohydrate nonglucoside conjugates.