The am ounts of free, conjugated (hydroxycinnamic acid amides) and insoluble (poly)amines (putres... more The am ounts of free, conjugated (hydroxycinnamic acid amides) and insoluble (poly)amines (putrescine, spermidine, spermine) as well as hydroxycinnamic acid esters (quinic acid esters) were determined during development of male inflorescences of Corylus avellana L. The location of these compounds either in sporophytic or gametophytic tissues and the possible correlation of their accumulation with exine formation are discussed.
Investigation of the marine sponge Dysidea avara, family Dysideidae, afforded a new sesquiterpene... more 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, protein kinase inhibition, inhibition of NFkB-activity and insecticidal activity were evaluated for the isolated compounds.
Three bacterial strains of marine origin were isolated during a screening for biosurfactants amon... more Three bacterial strains of marine origin were isolated during a screening for biosurfactants among n-alkane degrading microorganisms. One strain - identified as Alcaligenes sp. MM 1 - produced a novel glucose lipid. In the case of Arthrobacter sp. EK 1 the well-known trehalose tetraester was found as major component. From another pure culture classified as Arthrobacter sp. SI 1, extracellular emulsifying agents with properties indicating high molecular weight substances were detected. Furthermore trehalose corynomycolates were found at up to 2 g/1. The isolated biosurfactants showed good interfacial and emulsifying properties.
From the aerial parts of Melampodium divaricatum "Rich[ in Pers[# DC\ Asteraceae\ four new doubly... more From the aerial parts of Melampodium divaricatum "Rich[ in Pers[# DC\ Asteraceae\ four new doubly and eight new triply acylated 1!hydroxythymol 2!O!b!D!fucopyranosyl!"0:2#!b!D!fucopyranosides "seven compounds# and 1!hydroxythymol 2!O!b!D! fucopyranosyl!"0:2#!b!D!quinovopyranosides " _ve compounds# were isolated and their structures established by spectroscopic methods[ The acids involved in the acylation of the sugar moieties are angelic\ isovaleric\ 1!methylbutyric\ and acetic acid[ Þ 0888 Elsevier Science Ltd[ All rights reserved[
A detailed chemical investigation of the minor metabolites produced by the endophytic fungus Pest... more 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 ( ). 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.
The diacetylated lactonic sophorolipid from Candida bombolica was converted into the deacetylated... more The diacetylated lactonic sophorolipid from Candida bombolica was converted into the deacetylated acidic form by alkaline hydrolysis and subsequently treated with several glycosidases. One of these enzymes, a hesperidinase (E.C. 3.2.1.40), was most active in the specific release of one glucose molecule from the disaccharide lipid. The novel glucolipid was isolated and characterized. The surface and interfacial tension of aqueous
This review article presents our group's recent research findings with regard to bioactive na... more This review article presents our group's recent research findings with regard to bioactive natural products from marine sponges and tunicates, as well as from sponge derived fungi. The organisms discussed originate in the Indopacific region, which has an exceptionally rich marine biodiversity. Major topics that are covered in our review include the chemical ecology of sponges, focusing on defense against fishes, as well as the isolation and identification of new bioactive constituents from sponges and tunicates. Sponge derived fungi are introduced as an emerging source for new bioactive metabolites, reflecting the currently growing interest in natural products from marine microorganisms.
Fruits of Aglaia elliptica and leaves of A. harmsiana yielded seven insecticidal rocaglamide deri... more Fruits of Aglaia elliptica and leaves of A. harmsiana yielded seven insecticidal rocaglamide derivatives including five components which proved to be new natural products. Structure elucidation of the new compounds is described. All rocaglamide derivatives isolated exhibited strong insecticidal activity towards neonate larvae of the polyphagous pest insect Spodoptera littoralis when incorporated into an artificial diet with LC50 values varying
... 104, 315. 22. Meurer, B., Wray, V., Wiermann, R. and Strack, D. (1988) Phytochemistry 27, 839... more ... 104, 315. 22. Meurer, B., Wray, V., Wiermann, R. and Strack, D. (1988) Phytochemistry 27, 839. 23. Wfithrich, K. (1976) NMR in Biological Research. ... Matern, U. and Kneusel, RE (1988) Phyto parasitica 16, 153. 26. Graham, MY and Graham, TL (1991) Plant Physiol. 97, 1445. ...
Two new cyclic depsipeptide derivatives, kahalalides R (1) and S (2), together with two known con... more Two new cyclic depsipeptide derivatives, kahalalides R (1) and S (2), together with two known congeners, kahalalides F (3) and D (4), were isolated from the Indian sacoglossan mollusk Elysia grandifolia. The structures of the new compounds were unambiguously established on the basis of NMR spectroscopic ( 1 H, 13 C, COSY, HMBC) and mass spectrometric (FABMS, ESIMS, MALDI-TOF/PSD) data, which also included Marfey amino acid analyses. The new derivative kahalalide R was found to exert comparable or even higher cytotoxicity than the potential drug candidate kahalalide F toward the MCF7 human mammary carcinoma cell line.
Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics, 2013
The proapoptotic influenza A virus PB1-F2 protein contributes to viral pathogenicity and is prese... more The proapoptotic influenza A virus PB1-F2 protein contributes to viral pathogenicity and is present in most human and avian influenza isolates. The structures of full-length PB1-F2 of the influenza strains Pandemic flu 2009 H1N1, 1918 Spanish flu H1N1, Bird flu H5N1 and H1N1 PR8, have been characterized by NMR and CD spectroscopy. The study was conducted using chemically synthesized full-length PB1-F2 protein and fragments thereof. The amino acid residues 30-70 of PR8 PB1-F2 were found to be responsible for amyloid formation of the protein, which could be assigned to formation of β-sheet structures, although α-helices were the only structural features detected under conditions that mimic a membranous environment. At membranous conditions, in which the proteins are found in their most structured state, significant differences become apparent between the PB1-F2 variants investigated. In contrast to Pandemic flu 2009 H1N1 and PR8 PB1-F2, which exhibit a continuous extensive C-terminal α-helix, both Spanish flu H1N1 and Bird flu H5N1 PB1-F2 contain a loop region with residues 66-71 that divides the C-terminus into two shorter helices. The observed structural differences are located to the C-terminal ends of the proteins to which most of the known functions of these proteins have been assigned. A C-terminal helix-loop-helix motif might be a structural signature for PB1-F2 of the highly pathogenic influenza viruses as observed for 1918 Spanish flu H1N1 and Bird flu H5N1 PB1-F2. This signature could indicate the pathological nature of viruses emerging in the future and thus aid in the recognition of these viruses.
The am ounts of free, conjugated (hydroxycinnamic acid amides) and insoluble (poly)amines (putres... more The am ounts of free, conjugated (hydroxycinnamic acid amides) and insoluble (poly)amines (putrescine, spermidine, spermine) as well as hydroxycinnamic acid esters (quinic acid esters) were determined during development of male inflorescences of Corylus avellana L. The location of these compounds either in sporophytic or gametophytic tissues and the possible correlation of their accumulation with exine formation are discussed.
Investigation of the marine sponge Dysidea avara, family Dysideidae, afforded a new sesquiterpene... more 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, protein kinase inhibition, inhibition of NFkB-activity and insecticidal activity were evaluated for the isolated compounds.
Three bacterial strains of marine origin were isolated during a screening for biosurfactants amon... more Three bacterial strains of marine origin were isolated during a screening for biosurfactants among n-alkane degrading microorganisms. One strain - identified as Alcaligenes sp. MM 1 - produced a novel glucose lipid. In the case of Arthrobacter sp. EK 1 the well-known trehalose tetraester was found as major component. From another pure culture classified as Arthrobacter sp. SI 1, extracellular emulsifying agents with properties indicating high molecular weight substances were detected. Furthermore trehalose corynomycolates were found at up to 2 g/1. The isolated biosurfactants showed good interfacial and emulsifying properties.
From the aerial parts of Melampodium divaricatum "Rich[ in Pers[# DC\ Asteraceae\ four new doubly... more From the aerial parts of Melampodium divaricatum "Rich[ in Pers[# DC\ Asteraceae\ four new doubly and eight new triply acylated 1!hydroxythymol 2!O!b!D!fucopyranosyl!"0:2#!b!D!fucopyranosides "seven compounds# and 1!hydroxythymol 2!O!b!D! fucopyranosyl!"0:2#!b!D!quinovopyranosides " _ve compounds# were isolated and their structures established by spectroscopic methods[ The acids involved in the acylation of the sugar moieties are angelic\ isovaleric\ 1!methylbutyric\ and acetic acid[ Þ 0888 Elsevier Science Ltd[ All rights reserved[
A detailed chemical investigation of the minor metabolites produced by the endophytic fungus Pest... more 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 ( ). 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.
The diacetylated lactonic sophorolipid from Candida bombolica was converted into the deacetylated... more The diacetylated lactonic sophorolipid from Candida bombolica was converted into the deacetylated acidic form by alkaline hydrolysis and subsequently treated with several glycosidases. One of these enzymes, a hesperidinase (E.C. 3.2.1.40), was most active in the specific release of one glucose molecule from the disaccharide lipid. The novel glucolipid was isolated and characterized. The surface and interfacial tension of aqueous
This review article presents our group's recent research findings with regard to bioactive na... more This review article presents our group's recent research findings with regard to bioactive natural products from marine sponges and tunicates, as well as from sponge derived fungi. The organisms discussed originate in the Indopacific region, which has an exceptionally rich marine biodiversity. Major topics that are covered in our review include the chemical ecology of sponges, focusing on defense against fishes, as well as the isolation and identification of new bioactive constituents from sponges and tunicates. Sponge derived fungi are introduced as an emerging source for new bioactive metabolites, reflecting the currently growing interest in natural products from marine microorganisms.
Fruits of Aglaia elliptica and leaves of A. harmsiana yielded seven insecticidal rocaglamide deri... more Fruits of Aglaia elliptica and leaves of A. harmsiana yielded seven insecticidal rocaglamide derivatives including five components which proved to be new natural products. Structure elucidation of the new compounds is described. All rocaglamide derivatives isolated exhibited strong insecticidal activity towards neonate larvae of the polyphagous pest insect Spodoptera littoralis when incorporated into an artificial diet with LC50 values varying
... 104, 315. 22. Meurer, B., Wray, V., Wiermann, R. and Strack, D. (1988) Phytochemistry 27, 839... more ... 104, 315. 22. Meurer, B., Wray, V., Wiermann, R. and Strack, D. (1988) Phytochemistry 27, 839. 23. Wfithrich, K. (1976) NMR in Biological Research. ... Matern, U. and Kneusel, RE (1988) Phyto parasitica 16, 153. 26. Graham, MY and Graham, TL (1991) Plant Physiol. 97, 1445. ...
Two new cyclic depsipeptide derivatives, kahalalides R (1) and S (2), together with two known con... more Two new cyclic depsipeptide derivatives, kahalalides R (1) and S (2), together with two known congeners, kahalalides F (3) and D (4), were isolated from the Indian sacoglossan mollusk Elysia grandifolia. The structures of the new compounds were unambiguously established on the basis of NMR spectroscopic ( 1 H, 13 C, COSY, HMBC) and mass spectrometric (FABMS, ESIMS, MALDI-TOF/PSD) data, which also included Marfey amino acid analyses. The new derivative kahalalide R was found to exert comparable or even higher cytotoxicity than the potential drug candidate kahalalide F toward the MCF7 human mammary carcinoma cell line.
Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics, 2013
The proapoptotic influenza A virus PB1-F2 protein contributes to viral pathogenicity and is prese... more The proapoptotic influenza A virus PB1-F2 protein contributes to viral pathogenicity and is present in most human and avian influenza isolates. The structures of full-length PB1-F2 of the influenza strains Pandemic flu 2009 H1N1, 1918 Spanish flu H1N1, Bird flu H5N1 and H1N1 PR8, have been characterized by NMR and CD spectroscopy. The study was conducted using chemically synthesized full-length PB1-F2 protein and fragments thereof. The amino acid residues 30-70 of PR8 PB1-F2 were found to be responsible for amyloid formation of the protein, which could be assigned to formation of β-sheet structures, although α-helices were the only structural features detected under conditions that mimic a membranous environment. At membranous conditions, in which the proteins are found in their most structured state, significant differences become apparent between the PB1-F2 variants investigated. In contrast to Pandemic flu 2009 H1N1 and PR8 PB1-F2, which exhibit a continuous extensive C-terminal α-helix, both Spanish flu H1N1 and Bird flu H5N1 PB1-F2 contain a loop region with residues 66-71 that divides the C-terminus into two shorter helices. The observed structural differences are located to the C-terminal ends of the proteins to which most of the known functions of these proteins have been assigned. A C-terminal helix-loop-helix motif might be a structural signature for PB1-F2 of the highly pathogenic influenza viruses as observed for 1918 Spanish flu H1N1 and Bird flu H5N1 PB1-F2. This signature could indicate the pathological nature of viruses emerging in the future and thus aid in the recognition of these viruses.
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