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The bacterial dioxygenation of mono- or polycyclic aromatic compounds is an intensely studied field. However, only in a few cases has the repeated dioxygenation of a substrate possessing more than a single aromatic ring been described. We previously characterized the aryl-hydroxylating dioxygenase BphA-B4h, an artificial hybrid of the dioxygenases of the biphenyl degraders Burkholderia xenovorans LB400 and Pseudomonas sp. strain B4-Magdeburg, which contains the active site of the latter enzyme, as an exceptionally powerful biocatalyst. We now show that this dioxygenase possesses a remarkable capacity for the double dioxygenation of various bicyclic aromatic compounds, provided that they are carbocyclic. Two groups of biphenyl analogues were examined: series A compounds containing one heterocyclic aromatic ring and series B compounds containing two homocyclic aromatic rings. Whereas all of the seven partially heterocyclic biphenyl analogues were solely dioxygenated in the homocyclic ring, four of the six carbocyclic bis-aryls were converted into ortho,meta-hydroxylated bis-dihydrodiols. Potential reasons for failure of heterocyclic dioxygenations are discussed. The obtained bis-dihydrodiols may, as we also show here, be enzymatically re-aromatized to yield the corresponding tetraphenols. This opens a way to a range of new polyphenolic products, a class of compounds known to exert multiple biological activities. Several of the obtained compounds are novel molecules.

Chemical investigation of the Indonesian sponge Callyspongia aerizusa afforded five new cyclic peptides, callyaerins I-M (1-5), along with the known callyaerins A-G (6-12). The structures of the new compounds were unambiguously elucidated on the basis of one- and two-dimensional NMR spectroscopy and mass spectrometry. In addition, the structures of callyaerins D (9), F (11), and G (12), previously available in only small amounts, have been reinvestigated and revised. All compounds were tested in vitro against Mycobacterium tuberculosis, as well as against THP-1 (human acute monocytic leukemia) and MRC-5 (human fetal lung fibroblast) cell lines, in order to assess their general cytotoxicity. Callyaerins A (6) and B (7) showed potent anti-TB activity with MIC₉₀ values of 2 and 5 μM, respectively. Callyaerin C (8) was found to be less active, with an MIC₉₀ value of 40 μM. Callyaerin A (6), which showed the strongest anti-TB activity, was not cytotoxic to THP-1 or MRC-5 cells (IC₅₀ > 10 μM), which highlights the potential of these compounds as promising anti-TB agents.

Lantibiotics (lanthionine-containing antibiotics) from Gram-positive bacteria typically exhibit activity against Gram-positive bacteria. The activity and structure of pinensin A (1) and B (2), lantibiotics isolated from a native Gram-negative producer Chitinophaga pinensis are described. Surprisingly, the pinensins were found to be highly active against many filamentous fungi and yeasts but show only weak antibacterial activity. To the best of our knowledge, lantibiotic fungicides have not been described before. An in-depth bioinformatic analysis of the biosynthetic gene cluster established the ribosomal origin of these compounds and identified candidate genes encoding all of the enzymes required for post-translational modification. Additional encoded functions enabled us to build up a hypothesis for the biosynthesis, export, sensing, and import of this intriguing lantibiotic.

Flavonoids are known to possess a multitude of biological activities. Therefore, diversification of the core structures is of considerable interest. One of nature's important tailoring reactions in the generation of bioactive compounds is glycosylation, which is able to influence numerous molecular properties. Here, we examined two non-Leloir glycosyltransferases that use sucrose as an inexpensive carbohydrate donor, glycosyltransferase R from Streptococcus oralis (GtfR) and amylosucrase from Neisseria polysaccharea (Ams), for the glucosylation of flavonoids. Flavones generally were poor substrates. Several inhibited Ams. In contrast, flavanes were well accepted by both enzymes. All glucose attachments occurred via α1 linkages. Comparison of the three available stereoisomers of 3,5,7,3',4'-pentahydroxyflavane revealed significant differences in glycoside formation between them as well as between the two enzymes. The latter were shown to possess largely complementary product ranges. Altogether, three of the four hydroxy substituents of the terminal flavonoid rings were glycosylated. Typically, Ams glucosylated the B ring at position 3', whereas GtfR glucosylated this ring at position 4' and/or the A ring at position 7. In several instances, short carbohydrate chains were attached to the aglycones. These contained α 1-4 linkages when formed by Ams, but α 1-3 bonds when generated by GtfR. The results show that both enzymes are useful catalysts for the glucodiversification of flavanes. In total, more than 16 products were formed, of which seven have previously not been described.

‘Lateritin’ (1), a morpholine-2,5-dione (depsipeptide), was reinvestigated for its structure and absolute configuration. On the basis of thorough 1D and 2D NMR and mass spectrometrical analyses, the structure of 1 was revised to be identical with beauvericin (8) and confirmed that beauvericin (8) is the trimeric lactone of ‘lateritin’ (1). The absolute configuration was determined by acidic hydrolysis, followed by application of Marfey’s method, menthyl ester derivatization, and GC–MS analysis. In addition, the specific optical rotation values of the hydrolysis products were compared with those of available standards.

Five new flavone C-glycosides, including chrysin 6-C-(2″-O-α- l -rhamnopyranosyl)-β- d -glucopyranoside (1), chrysin 6-C-(2″-O-α- l -rhamnopyranosyl)-β- d -glucopyranosyl-7-O-β- d -glucopyranoside (2), chrysin 6-C-(2″-O-α- l -rhamnopyranosyl)-6′-deoxy-ribo-hexos-3-uloside (3), chrysin 6-C-(2″-O-α- l -rhamnopyranosyl)-β- l -fucopyranoside (4), chrysin 6-C-β-boivinopyranosyl-7-O-β- l -glucopyranoside (5), together with one known compound, isovitexin 2″-O-α- l -rhamnopyranoside (6), were isolated from leaves of Sarcotheca griffithii (Hook F) Hallier F (Oxalidaceae). Their structures were elucidated by analysis of the 1D, 2D NMR, and MS data, as well as by comparison with the literature data. This is the first report of secondary metabolites from the genus Sarcotheca.

Actinomycetales are known to produce various secondary metabolites including products with surface-active and emulsifying properties known as biosurfactants. In this study, the nonpathogenic actinomycetes Tsukamurella spumae and Tsukamurella pseudospumae are described as producers of extracellular trehalose lipid biosurfactants when grown on sunflower oil or its main component glyceryltrioleate. Crude extracts of the trehalose lipids were purified using silica gel chromatography. The structure of the two trehalose lipid components (TL A and TL B) was elucidated using a combination of matrix-assisted laser desorption/ionization time-of-flight/time-of-flight/tandem mass spectroscopy (MALDI-ToF-ToF/MS/MS) and multidimensional NMR experiments. The biosurfactants were identified as 1-α-glucopyranosyl-1-α-glucopyranosid carrying two acyl chains varying of C4 to C6 and C16 to C18 at the 2' and 3' carbon atom of one sugar unit. The trehalose lipids produced demonstrate surface-active behavior and emulsifying capacity. Classified as risk group 1 organisms, T. spumae and T. pseudospumae hold potential for the production of environmentally friendly surfactants.

The first naturally occurring trimeric anthracene derivatives, stemphylanthranols A and B (1 and 2), were obtained from the endophytic fungus Stemphylium globuliferum that had been isolated from Juncus actus 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.

Maytenus senegalensis Lam. (Celastraceae) leaves are traditionally used in West Africa for the management of cancer and other disorders associated with inflammation. In this study, bioactivity-guided fractionation of the methanol leaf extract of Maytenus senegalensis led to the isolation of 11 compounds, including the new phenyldilactone, maysedilactone ( 1 ). All isolated compounds were tested for cytotoxicity against mouse lymphoma cell line (L5178Y). Only (−) epigallocathechin showed high cytotoxicity and completely inhibited cell growth at the investigated dose of 10 μg/mL. This result supports the claimed efficacy of Maytenus senegalensis leaf extract in ethnomedicinal treatment of cancer.

Five new polyketide derivatives, 6′-hydroxypestalotiopsone C ( 1 ), acropyrone ( 2 ), bicytosporone D ( 3 ), waol acid ( 4 ), and pestalotiopene C ( 5 ), together with seven known metabolites ( 6 – 12 ), were obtained from extracts of the endophytic fungus Acremonium strictum , isolated from the mangrove tree Rhizophora apiculata . The structures of the isolated compounds were elucidated on the basis of comprehensive NMR and MS analysis. Compounds 6 , 7 , and 9 showed moderate cytotoxic activity against human cisplatin-sensitive (IC 50 values 27.1, 76.2, and 8.3 μM, respectively) and resistant A2780 cell lines (IC 50 values 12.6, 30.1, and 19.0 μM, respectively), whereas only 9 exhibited antibacterial activity against Staphylococcus aureus (MIC value 14.3 μM).

Chromatographic separation of a crude extract obtained from the fungus Aspergillus sp., isolated from the Mediterranean sponge Tethya aurantium , yielded a new tryptophan derived alkaloid, 3-((1-hydroxy-3-(2-methylbut-3-en-2-yl)-2-oxoindolin-3-yl)methyl)-1-methyl-3,4-dihydrobenzo[ e ][1,4]diazepine-2,5-dione ( 1 ), and a new meroterpenoid, austalide R ( 2 ), together with three known compounds ( 3 – 5 ). The structures of the new compounds were unambiguously elucidated on the basis of extensive one and two-dimensional NMR ( 1 H, 13 C, COSY, HMBC, and ROESY) and mass spectral analysis. Interestingly, the compounds exhibited antibacterial activity when tested against a panel of marine bacteria, with 1 selectively inhibiting Vibrio species and 2 showing a broad spectrum of activity. In contrast, no significant activity was observed against terrestrial bacterial strains and the murine cancer cell line L5178Y.

Chemical investigation of the endophytic fungus Penicillium citrinum cultured on white beans or on rice led to the isolation of two new alkaloids (1 and 2), along with fourteen known polyketides (6-12, 14-20) and four known alkaloids (3-5, and 13). The structures of the isolated compounds were determined by extensive analysis of the 1D, 2D NMR, and MS data, and by comparison with the literature. Compound 13, which had been previously obtained only by chemical synthesis, was isolated as a natural product for the first time, while compound 6 was firstly reported as a fungal metabolite. A re-isolation of sclerotinin A (14) revealed it to be a diastereoisomeric mixture (14a and 14b), whose stereochemistry was proposed for the first time based on ROESY experiment. All isolated compounds were evaluated for their cytotoxic and antibacterial activities. Compounds 12 and 17 showed significant cytotoxicity against the murine lymphoma cell line L5178Y with IC50 values of 1.0, and 0.78 μg/ml, respectively, while compounds 5, 11, and 15 were moderately active against Staphylococcus aureus ATCC 29213 (MIC 64 μg/ml).

Chemical investigation of the EtOAc extract of the mangrove-derived endophyte Corynespora cassiicola , isolated from Laguncularia racemosa (Combretaceae), afforded five new secondary metabolites, named coryoctalactones A–E ( 1 – 5 ). The structures of the new compounds were determined on the basis of 1D- and 2D-NMR spectroscopy as well as high-resolution mass spectrometry. The absolute configuration of the side chain in 1 – 3 and 5 were tentatively deduced based on biogenetic consideration in comparison with xestodecalactones, previously isolated from C. cassiicola . All isolated compounds were evaluated for their antimicrobial, cytotoxic, and antitrypanosomal activities.

Two bisdihydroanthracenone atropodiastereomeric pairs, including homodimeric flavomannin A (1) and the previously unreported flavomannin B (2), two new unsymmetrical dimers (3 and 4), and two new mixed dihydroanthracenone/anthraquinone dimers (5 and 6) were isolated from Talaromyces wortmannii , an endophyte of Aloe vera . The structures of 2-6 were elucidated by extensive NMR and mass spectrometric analyses. The axial chirality of the biaryls was determined using TDDFT ECD and VCD calculations, the combination of which however did not allow the assignment of the central chirality elements of 1. The compounds exhibited antibacterial activity against Staphylococcus aureus , including (multi)drug-resistant clinical isolates. Reporter gene analyses indicated induction of the SOS response for some of the derivatives, suggesting interference with DNA structure or metabolism. Fluorescence microscopy demonstrated defective segregation of the bacterial chromosome and DNA degradation. Notably, the compounds showed no cytotoxic activity, encouraging their further evaluation as potential starting points for antibacterial drug development.

Two new alkaloids, polycarpathiamines A and B (1 and 2), were isolated from the ascidian Polycarpa aurata. 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 (4), that was prepared by chemical synthesis. Compounds 1 and 2 both feature an uncommon 1,2,4-thiadiazole ring whose biosynthetic origin is proposed. Compound 1 showed significant cytotoxic activity against L5178Y murine lymphoma cells (IC50 0.41 μM).

Alkyl sophorosides, a special type of sophorolipids, can be produced using Candida bombicola cultures with glucose as main carbon source and 2-dodecanol as co-substrate. The dominating component, 2-dodecyl-sophoroside SL-E2-12, was purified via medium pressure liquid chromatography (MPLC) and used as substrate for further enzymatic modifications. Using β-glucuronidase in aqueous media the first modification gave a glycosidic cleavage of the acetyl glucose unit leading to 2-dodecyl-glucoside GL-A2-12. In a subsequent lipase-catalyzed acylation with sebacic acid in toluene this compound was functionalized regioselectively at the primary C-6′ position of glucose. Similar lipase-catalyzed reactions in toluene, but now using SL-E2-12 as acyl acceptor and unusual hydroxyl fatty acids – 3-hydroxy decanoic acid and 17-hydroxy stearic acid – as acyl donors, resulted in mono- and diacylations of primary hydroxyl positions of the sophorose unit (C-6′ and C-6′′) as shown by NMR and MS studies. In physicochemical characterization experiments the new glycoconjugates lowered the surface tension of water from 72 to 27–32 mN/m. Moreover it was observed that the new products inhibit the growth of particular Gram-positive bacteria. Additionally they indicate potential for anti-tumor promoting activity. Practical applications: According to literature data 2-alkyl-sophorosides can be produced using Candida bombicola cultures with yields of more than 20 g/L. Based on this starting material, 2-dodecyl-sophoroside, several regioselective enzymatic modifications were performed. Initially, β-glucuronidase catalysis in aqueous buffer solution gave 2-dodecyl-glucoside which was then successfully acylated at the C-6 position of glucose by lipase catalysis using a common dicarboxylic acid, sebacic acid. The resulting free carboxylic function of the acidic derivative opens up the possibility of achieving additional chemo-enzymatic reactions at this position for conversion, for instance, into polyesters. In addition lipase catalysis in organic solvents of 2-dodecyl-sophoroside allows acylation with unusual hydroxyl fatty acids of microbial origin. Physicochemical studies showed that these new glycoconjugates may be of interest for the cosmetic industry due to moisture conservation of the skin. For practical applications the conditions of the above biocatalytic reactions have been improved and scaled up.

Two new metabolites, embellicines A and B (1 and 2), were isolated from the EtOAc extract of the fungus Embellisia eureka , an endophyte of the Moroccan plant Cladanthus arabicus (Asteraceae). The structures of these new compounds were determined on the basis of extensive one- and two-dimensional NMR spectroscopy as well as by high-resolution mass spectrometry. The absolute configuration of embellicine A (1) was determined by TDDFT ECD calculations of solution conformers, whereas that of embellicine B (2) was deduced based on ROESY correlations and on biogenetic considerations in comparison to 1. Both embellicines (1 and 2) are cytostatic, cytotoxic, and inhibit NF-κB transcriptional activity, indicating that inhibition of NF-κB may be a possible mechanism of action of these compounds. Embellicine B (2) was the most active compound encountered in this study and acts at nanomolar concentrations without affecting tumor microenvironment.

Three new polyketides (-)-1, (+)-1, and 2) were isolated from the EtOAc extract of the fungus Embellisia eureka, an endophyte of the Moroccan plant Cladanthus arabicus (Asteraceae). The structures of these new compounds were determined on the basis of one- and two-dimensional NMR spectroscopy as well as by high-resolution mass spectrometry. The absolute configurations of (-)-1, (+)-1, and 2 were determined by TDDFT ECD calculations of solution conformers, online HPLC-ECD analysis, and the modified Mosher method. Chirality 25:250–256, 2013. © 2013 Wiley Periodicals, Inc.

Chemical investigation of the endophytic fungus Talaromyces wortmannii, isolated from Aloe vera, yielded two new cyclic peptides, talaromins A and B. Their structures were established on the basis of extensive NMR spectroscopic and mass spectrometric analysis. Both cyclopeptides contain ring systems comprised of six α-amino acid residues connected to a β-amino acid. The absolute configurations of the α-amino acids were determined by Marfey’s method.

Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for the structure elucidation of antibiotics in solution. Over the past 30 years there have been numerous publications describing the use of NMR to characterize naturally derived or synthetic antibiotics. A large number of one-dimensional (1D) and two-dimensional (2D) NMR methods are available today and the list continues to expand. In this chapter, we will consider the key NMR experiments that provide useful information for compound structure elucidation.

Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for the structure elucidation of antibiotics in solution. Over the past 30 years there have been numerous publications describing the use of NMR to characterize naturally derived or synthetic antibiotics. A large number of one-dimensional (1D) and two-dimensional (2D) NMR methods are available today and the list continues to expand. In this chapter, we will consider the key NMR experiments that provide useful information for compound structure elucidation.

Flavonoids possess a wide range of biological activities. Their glycosylation is of considerable interest, as it often positively influences their pharmacokinetic and other molecular properties. We recently showed that two non-Leloir glycosyltransferases that use sucrose as carbohydrate donor, an amylosucrase from Neisseria polysaccharea (Ams-Np) and a glucansucrase from Streptococcus oralis (GtfR-So), were hardly able to glucosylate flavones, but accepted flavanes as substrates. We now examined compounds from two other flavonoid classes, flavanones and isoflavones for glucose transfer by these enzymes. Taxifolin was investigated as a flavanone analogue of both, the accepted pentahydroxyflavane catechin and the non-accepted pentahydroxyflavone quercetin. It was glucosylated by both enzymes, but much better by GtfR-So than by Ams-Np due to apparent strong inhibition of the latter. The acceptance of a collection of isoflavones strongly depended on the substitution pattern of the core. Only two of the 10 compounds examined yielded glucosides in satisfactory amounts. With these substrates, both enzymes catalyzed formation of a range of products, differing in the number of saccharide units. The structures of mono- and diglycosylated compounds obtained in higher amounts were elucidated. While GtfR-So attached glucose to taxifolin in the B ring at O4', both enzymes glucosylated the isoflavones in the A ring at O7. All products were α-glucosides. Interglycosidic linkages formed by Ams-Np were α1-4. To our knowledge, this is the first report of glucosylation of flavanone and isoflavone aglycones by an amylosucrase. All characterized compounds have not previously been described.

Seven new alkaloids including tryptoquivaline K (1) and fumiquinazolines K–P (2–7), bearing a rare 1-aminocyclopropane-1-carboxylic acid residue, together with six known compounds (8–13), were isolated from the fungus Aspergillus sp. obtained from the Mediterranean sponge Tethya aurantium. The structures of the new compounds were determined by extensive analysis by 1D and 2D NMR spectroscopy and mass spectrometry. The absolute configurations of tryptoquivaline K (1) and fumiquinazolines K and L (2, 3) were determined by TDDFT ECD calculations of their solution conformers, and the configurational assignment of the related fumiquinazolines M–P (4–7) was achieved by comparison of their ECD spectra with those of compounds 2 and 3. All compounds were evaluated for their cytotoxic activity by the MTT method. Compound 8 exhibited pronounced cytotoxicity against the mouse lymphoma cell line (L5178Y) with an IC50 value of 3.6 μM, but only moderate activity was observed against human ovarian cancer (A2780) and human Philadelphia chromosome-positive chronic myelogenous leukemia (K562) cell lines with IC50 values of 18.5 and 15.0 μM, respectively.

Chemical investigation of the Indonesian marine sponge Stylissa species, which was collected at 2008 from Derawan Islands, Berau, NE Kalimantan, Indonesia offered four new brominated alkaloids, including 12-N-methyl stevensine (1), 12-N-methyl-2-debromostevensine (2), 3-debromolatonduine B methyl ester (3), 3-debromolatonduine A (4) together with eight known alkaloids identified as Z-hymenialdisine, Z-debromohymenialdisine, Stevensine, 2-debromostevensine, 3-bromoaldizine, 3,4-dibromopyrrole-2-carbamide, latonduine A, and latonduine B methyl ester (5–12), respectively. The structures of all isolated compounds were unambiguously elucidated based on extensive 1D and 2D NMR spectroscopy and HRMS analysis as well as comparison with those reported in literature. All isolated compounds were tested for their cytotoxicity against mouse lymphoma cell line L5187Y. The results showed that only 1, 5, 6, and 11 showed significant in vitro activity with EC50 values of 3.5, 1.8, 2.1, and 9.0 μg/mL, respectively.

Five farinomalein derivatives including three new compounds, farinomaleins C–E (3–5), and one new isoindoline congener (6) were isolated from an unidentified endophytic fungus obtained from the inner tissues of healthy leaves of the mangrove plant Avicennia marina from Oman. The structures of the new compounds were unambiguously elucidated on the basis of their mass, as well as one and two dimensional NMR spectroscopic data.

The endophytic fungus Penicillium glabrum was isolated from pomegranate fruits (Punica granatum) collected in Uzbekistan. Extracts of the fungus grown on rice yielded two new styrylpyrones, namely 3-methyldesmethoxyyangonin (1) and 3-methylbisnoryangonin (2), together with four known metabolites. The structures of the isolated compounds were elucidated on the basis of comprehensive spectral analysis (1D and 2D NMR and MS).

Three new anthracene derivatives, which include tetrahydroanthraquinone 1 and two tetrahydroanthraquinone heterodimers 2 and 3, were isolated from Stemphylium globuliferum, together with four known metabolites 4–7. Detailed analysis of the spectroscopic data allowed the unambiguous determination of the structures of 1 and 2 and a revision of the structure of alterporriol C and its atropisomer. Furthermore, alterporriol G, previously obtained as part of a mixture, was isolated in its pure form for the first time and its structure was also revised. The absolute configurations of 1, 2 and 3 were assigned by calculation of their CD spectra, which also allowed the configurational assignment of altersolanol A and the determination of the axial chirality of alterporriols D and E. All isolated compounds were analysed for their antimicrobial and cytotoxic activities. Compounds 1 and 5 inhibited the growth of most pathogenic microorganisms tested, whereas 2, 6 and 7 showed selective inhibition of bacteria but were inactive against fungi.

Chromatographic separation of a crude extract obtained from the fungus Aspergillus sp., isolated from the Mediterranean sponge Tethya aurantium, yielded five new meroterpenoid metabolites, austalides M–Q (1–5), together with nine known compounds (6–13). The structures of the new compounds were unambiguously elucidated on the basis of extensive 1D and 2D NMR methods and by mass spectral analysis. Furthermore, the absolute configurations of 1 and 4 were determined by time-dependent density functional theory electronic circular dichroism (TDDFT ECD) calculations, allowing the assignment of the absolute configuration of analogous compounds 2, 3, and 5. The calculations revealed that the conformation of the benzene-fused phthalide chromophore, which is sensitive to even minor changes in its proximity, is decisive for the ECD parameters, rendering a simple ECD comparison of related homochiral austalides difficult. All compounds were evaluated for their cytotoxic activity against murine cancer cell line L5178Y by using the MTT method. Compounds 8 and 11 exhibited moderate to pronounced cytotoxicity, with IC50 values of 39.4 and 0.2 μM, respectively, whereas the remaining investigated compounds showed either weak or no activity in this assay.

Bioassay-guided fractionation of a methanolic extract of the fungus Arthrinium sp., isolated from the Mediterranean sponge Geodia cydonium, afforded 10 natural products including five new diterpenoids, arthrinins A-D (1-4) and myrocin D (5). In addition, five known compounds were obtained, which included myrocin A (6), norlichexanthone (7), anomalin A (8), decarboxycitrinone (9) and 2,5-dimethyl-7-hydroxychromone (10). The structures of all isolated compounds were unambiguously elucidated based on extensive 1D and 2D NMR and HR-MS analyzes. The absolute configuration of arthrinins A-D (1-4) was established by the convenient Mosher method performed in NMR tubes and by interpretation of the ROESY spectra. Antiproliferative activity of the isolated compounds was assessed in vitro against four different tumor cell lines, including mouse lymphoma (L5178Y), human chronic myelogenous leukemia (K562), human ovarian cancer (A2780) and cisplatin-resistant ovarian cancer cells (A2780CisR), using the MTT assay. Norlichexanthone (7) and anomalin A (8) exhibited the strongest activities with IC₅₀ values ranging from 0.40 to 74.0 μM depending on the cell line investigated. This was paralleled by the inhibitory activity of both compounds against 16 cancer related protein kinases including aurora-B, PIM1, and VEGF-R2. In vitro IC₅₀ values of 7 and 8 against these three protein kinases ranged from 0.3 to 11.7 μM. Further investigation of the potential antitumoral activity of compounds 5-8 was performed in an in vitro angiogenesis assay against human umbilical vascular endothelial cells (HUVEC) sprouting induced by vascular endothelial growth factor A (VEGF-A). Anomalin A (8), myrocin D (5) and myrocin A (6) inhibited VEGF-A dependent endothelial cell sprouting with IC₅₀ values of 1.8, 2.6 and 3.7 μM, respectively, whereas norlichexanthone (7) was inactive.

Structure elucidation and conformation analysis of four proanthocyanidins isolated from the bark of Parapiptadenia rigida were performed by two-dimensional NMR spectroscopy, HRESIMS, CD, and molecular mechanics (MM+) force field calculations. The known prodelphinidin, epigallocatechin-(4β→8)-epigallocatechin-3-O-gallate (1) was accompanied by the new epigallocatechin-(4β→8)-4'-O-methylgallocatechin (2), epicatechin-(4β→8)-4'-O-methylgallocatechin (3), and (4α→8)-bis-4'-O-methylgallocatechin (4). Compound 4 was previously published but the earlier structure must presumably be revised to 4'-O-methylgallocatechin-(4α→8)-4'-O-methylepigallocatechin. Conformational studies showed the compact rotamer with B and E rings in quasi-equatorial orientations as the preferred conformation for compounds 1-3, whereas 4 consists of two stable rotamers, each with a quasi-equatorial orientation of ring B and E, respectively. The isolated compounds were studied for their wound-healing effects in a scratch assay and showed promising results.

Chemical examination of the fungus Aspergillus ustus isolated from the Mediterranean sponge Suberites domuncula yielded the five new ophiobolin-type sesterterpenoids 1–5 and the two new pyrrolidine alkaloids 6 and 7, together with the known compound aurantiamine and cerebroside D. The structures of the new compounds were unambiguously elucidated on the basis of extensive spectroscopic-data analysis (1D- and 2D-NMR, MS, and UV) and comparison with literature data. All compounds were evaluated for their cytotoxicity against murine lymphoma cell line L5178Y.

Chemical examination of the endophytic fungus Pestalotiopsis sp., isolated from the leaves of the Chinese mangrove Rhizophora mucronata, yielded a new amide called pestalotiopamide E (1). The structure of the new compound was unambiguously elucidated on the basis of extensive spectroscopic data analysis.

A detailed chemical investigation of the minor metabolites produced by the endophytic fungus Pestalotiopsis sp. isolated from the Chinese mangrove Rhizophora mucronata afforded sixteen new compounds of polyketide origin, including pestalotiopyrones A–H (1–8), pestalotiopisorin A (10), pestalotiollides A–B (11–12), pestalotiopin A (13), and four amides pestalotiopamides A–D (14–17), along with three known compounds, nigrosporapyrone D (9), 2-anhydromevalonic acid (18), and p-hydroxy benzaldehyde (19). The structures of all compounds were unambiguously established from their spectroscopic data that included HR-ESIMS and 1- and 2-dimensional NMR spectroscopy, and by comparison with the literature.

Bioassay guided fractionation of the EtOAc fraction of the sponge Callyspongia aerizusa yielded seven new cytotoxic cyclic peptides callyaerins A-F (1-6) and H (8). Their structures were determined using extensive 1D (1H, 13C and DEPT) and 2D (COSY, HMQC, HMBC, TOCSY, and ROESY) NMR and mass spectral (ESI and HRESI-TOF) data. All compounds were cyclic peptides containing ring systems of 5-9 amino acids and side chains of 2-5 amino acids in length. An unusual (Z)-2,3-diaminoacrylic acid unit provided the template for ring closure and afforded the linkage to the peptidic side chain which was always initiated with a proline moiety. All peptides contained three or more proline residues and the remaining residues were predominantly hydrophobic residues with all amino acids present in the l form. Callyaerins A-F (1-6) and H (8) showed biological activity in antibacterial assays and in various cytotoxicity assays employing different tumour cell-lines (L5178Y, HeLa, and PC12). Callyaerins E (5) and H (8) exhibited strong activity against the L5178Y cell line with ED50 values of 0.39 and 0.48 microM, respectively. On the other hand, callyaerin A (1) showed strong inhibitory properties towards C. albicans.

Fifty-seven samples have been analyzed with regard to the occurrence of dimeric procyanidins B1-B8 as well as the composition of polymeric procyanidins. Fifty-two samples were found to contain polymeric procyanidins. In most of the samples, (-)-epicatechin was the predominant unit present. In white willow bark (Salix alba), however, large amounts of (+)-catechin (81.0%) were determined by means of phloroglucinolysis. White willow bark has therefore been used for the semisynthetic formation of dimeric procyanidins B3 [(+)-C-4alpha --> 8-(+)-C)], B4 [(+)-C-4alpha --> 8-(-)-EC)], B6 [(+)-C-4alpha --> 6-(+)-C)], and B8 [(+)-C-4alpha --> 6-(-)-EC)]. The reaction mixtures of the semisynthesis were successfully fractionated with high-speed countercurrent chromatography (HSCCC), and dimeric procyanidins B3, B4, B6, and B8 were obtained on a preparative scale.

The yeast Candida bombicola ATCC 22214 is well-known to produce mixtures of glycolipids containing the sugar sophorose, the so-called sophorolipids, especially when cultivated on hydrophobic carbon sources as co-substrates. To improve cultivation efficiency, an integrated process was developed using ultrasound separation technology. Since this technology is new for use with C. bombicola, it was first characterized in batch experiments and afterwards implemented in an integrated production process. In this process, separation efficiencies of about 99% C. bombicola cells could be achieved, leading to 8 g/L of nearly cell-free sophorolipid product and a total amount of 73.8 g/L sophorolipids. Furthermore, a technical mixture of unusual branched fatty alcohols containing mainly 2-hexyl-1-decanol was used as co-substrate with glucose in a shake flask study. This resulted in the production of a new product, 1-O-β-glucopyranosyl-2-hexyldecanol, a molecule containing glucose as the sugar moiety and 2-hexyl-1-decanol as a branched hydrophobic side chain.

Two stilbenes, trans-resveratrol and (-)-epsilon-viniferin, as well as a mixture of both, were biotransformed using horseradish peroxidase and hydrogen peroxide. Under the applied conditions trans-resveratrol afforded one major product, which was identified as trans-delta-viniferin, a resveratrol-trans-dehydrodimer. Large-scale biotransformation of a mixture of trans-resveratrol and (-)-epsilon-viniferin yielded two novel resveratrol trimers, resviniferin A and resviniferin B, which were obtained in a pure form after fractionation by high-speed countercurrent chromatography and final purification by preparative HPLC. Their structures were established by means of mass spectrometry and 2D NMR spectroscopic analyses, including HSQC, HMBC, COSY, and ROESY.

Chemical investigation of Indonesian marine sponges Agelas linnaei and A. nakamurai afforded 24 alkaloid derivatives representing either bromopyrrole or diterpene alkaloids. A. linnaei yielded 16 bromopyrrole alkaloids including 11 new natural products with the latter exhibiting unusual functionalities. The new compounds include the first iodinated tyramine-unit bearing pyrrole alkaloids, agelanesins A-D. These compounds exhibited cytotoxic activity against L5178Y mouse lymphoma cells with IC(50) values between 9.25 and 16.76 muM. Further new compounds include taurine acid substituted bromopyrrole alkaloids and a new dibromophakellin derivative. A. nakamurai yielded eight alkaloids among them are three new natural products. The latter include the diterpene alkaloids (-)-agelasine D and its oxime derivative and the new bromopyrrole alkaloid longamide C. (-)-Agelasine D and its oxime derivative exhibited cytotoxicity against L5178Y mouse lymphoma cells (IC(50) 4.03 and 12.5 microM, respectively). Furthermore, both agelasine derivatives inhibited settling of larvae of Balanus improvisus in an anti-fouling bioassay and proved to be toxic to the larvae. (-)-Agelasine D inhibited the growth of planktonic forms of biofilm forming bacteria S. epidermidis (MIC

A detailed chemical study of the aerial parts of Tamarix nilotica (Tamaricaceae) from Saudi Arabia led to the isolation of a new pentacyclic triterpenoid, 3-O-trans-caffeoylisomyricadiol, in addition to nine known compounds. The structures of all isolated compounds were unambiguously elucidated by 1D, 2D NMR, and mass spectrometry. In the radical scavenging (DPPH) assay, 3-O-trans-caffeoylisomyricadiol exhibited potent antioxidant activity with an IC50 value of 3.56 μM, while that for quercetin (standard antioxidant) was 5.72 μM

Two new jaspamide derivatives 2 and 3, together with the parent compound jaspamide (1) have been isolated from the marine sponge Jaspis splendens collected in Kalimantan (Indonesia). The structures of the new compounds were unambiguously elucidated based on 1D and 2D NMR spectral data, mass spectrometry and comparison with jaspamide (1). The new derivatives inhibited the growth of mouse lymphoma (L5178Y) cell line in vitro with IC(50) values of

Seven new drimane sesquiterpenoids (1-3, 6-9), along with the known compounds deoxyuvidin B (4), strobilactone B (5), and RES-1149-2 (10), were obtained from cultures of the fungus Aspergillus ustus, which was isolated from the marine sponge Suberites domuncula. Their structures were established by means of spectroscopic analyses including one- and two-dimensional NMR spectroscopy and high-resolution MS. Compounds 6, 7, and 10 showed cytotoxic activity against a panel of tumor cell lines, including L5178Y, HeLa, and PC12 cells, with 7 being the most active (EC(50) against L5178Y cell line: 0.6 microg/mL).

1 A hitherto unidentified endophytic strain of the genus Chaetomium, isolated from the medicinal plant Otanthus maritimus, yielded a new tetrahydrofuran derivative, aureonitolic acid (), along with 5 known natural products, 2 - 6. The structure of 1 was determined by extensive spectroscopic analysis and comparison with reported data. Extracts of the fungus, grown either in liquid culture or on solid rice media, exhibited considerable cytotoxic activity when tested in vitro against L5178Y mouse lymphoma cells. Compounds 2 and 6 showed significant growth inhibition against L5178Y cells with EC50 values of 7.0 and 2.7 μg/mL, respectively, whereas 1 was inactive

Pituitary adenylate cyclase activating polypeptide (PACAP) occurs in two bioactive forms, PACAP-38 and PACAP-27 that have identical N-terminal sequences but differ by the presence of a C-terminal 11 residue elongation in the former. Although VIP and PACAP have several similar biological actions due to their amino acid sequence similarity, we have found that they evoke opposite responses in the guinea pig gallbladder smooth muscle, where PACAP induces contraction while VIP causes relaxation. In addition the response to PACAP-38 is four times lower than that of PACAP-27. In a previous study we have reported the role of the N-terminal α-helical regions of PACAP-27 which play a key role in gallbladder contraction. In the present study the biological action on the guinea pig gallbladder was investigated using a synthetic mini-library of C-terminally deleted peptides related to PACAP-38. The effects caused by residues within the C-terminus are not a result of a response via the M-receptor or Na+ channel, but most likely arise from a delicate balance between the differential effects of PACAP-38 on specific PAC1 and VPACs receptors.

Branched beta-1,3/1,6-glucans (scleroglucan) were produced by cultivation of Sclerotium rolfsii ATCC 15205. Regioselective hydrolysis at the beta-1,3-linkage of the cell-free and purified polysaccharide was performed in borosilicate glass bottles at pH 5, 121 degrees C, and 1 bar for 72 h. The mixture was divided into four molar mass fractions by stepwise cross-flow filtration using different cutoffs. In vitro studies revealed that scleroglucan hydrolysates with a low molar mass of less than 5 kDa significantly stimulated the activation and maturation of porcine monocyte derived dendritic cells (MoDC) by upregulation of CD40 and CD80/86 as well as by reduction of antigen uptake. MoDC treated with low molar mass scleroglucan showed a considerable increase in the amounts of secreted proinflammatory cytokine tumor necrosis factor alpha and stimulated the proliferation of lymphocytes. Therefore, scleroglucan molecules of low molecular weight are able to induce activation and maturation of porcine DC, which are key initiators of inflammatory and adaptive immune responses, and could provide improved protection against infectious diseases.

Summary The opportunistic bacterium Pseudomonas aeruginosa synthesizes significant amounts of an additional phospholipid, identified as 2′ alanyl-phosphatidylglycerol (A-PG), when exposed to acidic growth conditions. At pH 5.3 A-PG contributed up to 6% to the overall lipid content of the bacterium. Sequence analysis of P. aeruginosa revealed open reading frame PA0920 showing 34% sequence identity to a protein from Staphylococcus aureus involved in tRNA-dependent formation of lysyl-phosphatidylglycerol. The P. aeruginosa deletion mutant ΔPA0920 failed to synthesize A-PG. Heterologous overproduction of PA0920 in Escherichia coli resulted in the formation of significant amounts of A-PG, otherwise not synthesized by E. coli. Consequently, the protein encoded by PA0920 was named A-PG synthase. The enzyme was identified as an integral component of the inner membrane. The protein was partially purified by detergent solubilization and subjected to an in vitro activity assay. tRNAAla-dependent catalysis was demonstrated. Transcriptional analysis of the corresponding gene in P. aeruginosa using lacZ reporter gene fusion under various pH conditions indicated a 4.4-fold acid-activated transcription. A phenotype microarray analysis was used to identify further conditions for A-PG function.