Furan oligomers and beta-carbolines from terrestrial streptomycetes.

2,5-Bis(hydroxymethyl)furan monoacetate (3) and 2,5-bis(hydroxymethyl)furan diacetate (4) were obtained as new natural products from an ethyl acetate extract of the terrestrial Streptomyces sp. isolate GW11/1695. Another Streptomyces isolate, GW21/1313, delivered a dimer (6) and a trimer (7) of (hydroxymethyl)furfural. The latter strain also produced 4-hydroxy-2-(5-(hydroxymethyl)furan-2-ylmethylene)-5-methylfuran-3-one (5), perlolyrin (8), and two new beta-carboline derivatives, 9 and 10. 2,5-Bis(hydroxymethyl)furan diacetate (4) exhibited weak cytotoxic activity against brine shrimp larvae.

Kettapeptin: isolation, structure elucidation and activity of a new hexadepsipeptide antibiotic from a terrestrial Streptomyces sp.

The ethyl acetate extract of the Streptomyces sp. isolate GW99/1572 exhibited significant biological activity against Gram-positive bacteria and delivered kettapeptin (1), a new hexadepsipeptide antibiotic of the azinothricin type. The structure was elucidated by various 1D and 2D NMR techniques, mass spectrometry and by comparison of the NMR data with those of closely related antibiotics. The absolute configuration of the compound was derived by crystal structure analysis and by comparison with the optical rotation data of related compounds.

1-Hydroxy-1-norresistomycin and resistoflavin methyl ether: new antibiotics from marine-derived streptomycetes.

Cultivation of the marine-derived streptomycete isolate B8005 delivered three known antibiotics, resistomycin (1), resistoflavin (3a) and tetracenomycin (4), and a further member of the rare resistomycin class, the weakly antibiotically active 1-hydroxy-1-norresistomycin (2). From a related marine strain B4842, 1 and resistoflavin methyl ether (3b) have been isolated. The formation of 2 is of interest from a biosynthetic point of view.

Sorbicillin analogues and related dimeric compounds from Penicillium notatum.

In our screening of microorganisms for new natural products, the fungus Penicillium notatum delivered further members of the sorbicillin family, namely, the sohirnones A [3, 1-(2,4-dihydroxy-5-methylphenyl)hex-4-en-1-one], B [4a, 1-(2,4,5-trihydroxy-3,6-dimethylphenyl)hexa-2,4-dien-1-one], and C [5, 1-(2,4,5-trihydroxy-3,6-dimethylphenyl)hex-4-en-1-one]. A stable tautomer of oxosorbicillinol (7) was characterized as 6, and the recently described 7-deacetoxyyanuthone (8) was reisolated. The additionally isolated rezishanones A-D (12-13c) are the first natural Diels-Alder products of sorbicillinol (1) with dienophiles not related with 1. The monomers and dimers showed weak antibacterial activity, but were inactive against fungi and algae. The structures were determined by spectroscopic methods and by comparison of the NMR data with those of the structurally related 2',3'-dihydrosorbicillin (2) and, in the case of 4a, by transformation into the known sorrentanone (4b).

Chinikomycins A and B: isolation, structure elucidation, and biological activity of novel antibiotics from a marine Streptomyces sp. isolate M045.

In our screening of marine Streptomycetes for bioactive principles, two novel antitumor antibiotics designated as chinikomycins A (2a) and B (2b) were isolated together with manumycin A (1), and their structures were elucidated by a detailed interpretation of their spectra. Chinikomycins A (2a) and B (2b) are chlorine-containing aromatized manumycin derivatives of the type 64-pABA-2 with an unusual para orientation of the side chains. They exhibited antitumor activity against different human cancer cell lines, but were inactive in antiviral, antimicrobial, and phytotoxicity tests.

Quinazolin-4-one derivatives from Streptomyces isolates.

From the ethyl acetate extract of the strain Streptomyces sp. isolate GW23/1540, besides 16 known products, several 1H-quinazolin-4-one derivatives were isolated. (SR)-2-(1-Hydroxyethyl)-2-methyl-2,3-dihydro-1H-quinazolin-4-one (4) and (RR)-2-(1-hydroxyethyl)-2-methyl-2,3-dihydro-1H-quinazolin-4-one (5) are new natural products. 2-Methyl-3H-quinazolin-4-one (2) and 1H-quinazoline-2,4-dione (3) are known from other bacteria and plants, respectively. From another Streptomyces sp., GW2/577, 5-methyl-1H-quinazoline-2,4-dione (6) was isolated and the structure proven by comparison with the isomeric 7. The new natural products showed no activity against the microalgae Chlorella vulgaris, Chlorella sorokiniana, and Scenedesmus subspicatus, the fungus Mucor miehei, the yeast Candida albicans, and the bacteria Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Streptomyces viridochromogenes.

Anti-cancer and antibacterial trioxacarcins with high anti-malaria activity from a marine Streptomycete and their absolute stereochemistry.

The ethyl acetate extract from the Streptomyces sp. isolate B8652 delivered the trioxacarcins A to approximately C (2a to approximately 2c) and additionally three new derivatives designated as trioxacarcins D to approximately F (2d to approximately 2f). All trioxacarcins showed high anti-bacterial and some of them high anti-tumor and anti-malaria activity. The structures of the new antibiotics were derived from mass, 1D and 2D NMR spectra and confirmed by comparison of the NMR data with those of known derivatives. The absolute configuration of the trioxacarcins is deduced from the X-ray analysis of gutingimycin (2g) and from the known stereochemistry of the L-trioxacarcinoses A and B.

Chandrananimycins A approximately C: production of novel anticancer antibiotics from a marine Actinomadura sp. isolate M048 by variation of medium composition and growth conditions.

In our screening of marine actinomycetes for bioactive principles, three novel antibiotics designated as chandrananimycin A (3c), B (3d) and C (4) were isolated from the culture broth of a marine Actinomadura sp. isolate M045. The structures of the new antibiotics were determined by detailed interpretation of mass, 1D and 2D NMR spectra.

Seitomycin: isolation, structure elucidation and biological activity of a new angucycline antibiotic from a terrestrial Streptomycete.

A new antibiotic, named seitomycin (1c), and the known microbial metabolite tetrangulol methyl ether (2) were found in the ethyl acetate extract of two terrestrial Streptomyces sp. isolates. The structure of the new antibiotic was elucidated by spectroscopic studies and by comparison of the NMR data with the structurally related hatomarubigin C (1a) and SM-196 B (1b). Seitomycin (1c) showed moderate antimicrobial and weak phytotoxic activity, similar to tetrangulol methyl ether (2).

Isolation, structure elucidation and biological activity of 8-O-methylaverufin and 1,8-O-dimethylaverantin as new antifungal agents from Penicillium chrysogenum.

In the screening of fungi for bioactive components, 8-O-methylaverufin (1b) and 1,8-O-dimethylaverantin (2b) were isolated from the culture broth of Penicillium chrysogenum. The structure of these new antibiotics were determined by interpretation of the 1D and 2D NMR spectra and by comparison of the NMR data with those of the structurally related averufin (1a) and averantin (2a). Both compounds have moderate antifungal activity.

Bhimamycin A to approximately E and bhimanone: isolation, structure elucidation and biological activity of novel quinone antibiotics from a terrestrial Streptomycete.

From the ethyl acetate extract of a terrestrial Streptomycete isolate, five new quinone antibiotics, bhimamycin A (2a), B (2b), C (3c), D (5a), E (7) and the new tetralone bhimanone (8) were isolated together with the known microbial products chrysophanol (1a), aloesaponarin II (1b), 3,8-dihydroxy-1-methylanthraquinone-2-carboxylic acid (1c), adenosine, 2'-deoxyadenosine, phenylacetamide, and 2-(p-hydroxyphenyl)ethanol. The structures of these natural products were deduced from the spectral data and confirmed by comparison with related compounds from the literature and by synthesis.

Himalomycin A and B: isolation and structure elucidation of new fridamycin type antibiotics from a marine Streptomyces isolate.

In our screening of marine Streptomycetes for bioactive compounds, in addition to the known metabolites rabelomycin (1), fridamycin D (2b), N-benzylacetamide and N-(2'-phenylethyl)acetamide, two new anthracycline antibiotics designated as himalomycin A (2c) and B (2d) were isolated from the culture broth of the marine Streptomyces sp. isolate B6921. The structure of the new antibiotics was determined by comparison of the NMR data with those of fridamycin D (2b) and by detailed interpretation of mass, 1D and 2D NMR spectra.

Pharacine, a natural p-cyclophane and other indole derivatives from Cytophaga sp. strain AM13.1.

From the ethyl acetate extract of the bacterial strain Cytophaga sp. AM13.1, among many known compounds, the new natural products 2,5-bis(3-indolylmethyl)pyrazine (2) and a highly symmetrical p-cyclophane named pharacine (5) were identified. In addition, tryptamine isovalerate (1) and p-hydroxyphenylacetamide (4), known as plant metabolites, were isolated and characterized from a microorganism for the first time. The new natural products showed no activity against three microalgae, the fungus Mucor miehei, the yeast Candida albicans, and the bacteria Staphylococcus aureus, Bacillussubtilis, Escherichia coli, and Streptomyces viridochromogenes.

Phytotoxic arylethylamides from limnic bacteria using a screening with microalgae.

N-Phenylethylamides 1a-1f, were isolated from cultures of three limnic strains GW90a, GW102a and GW73a. Strain GW102a delivered additionally the compound cyclo(isoleucyldehydroalanyl) (2). The structure of these compounds were assigned by a detailed spectral analysis. Due to their potential use as herbicides, various related compounds 1a, 3, 4a and 4b were synthesized. The minimum inhibitory concentration (MIC) against Chlorella vulgaris, Chlorella sorokiniana, Chlorella salina and Scenedesmus subspicatus ranged from 100 to 12.5 microg/ml. All these amides were found to be inactive against Mucor miehei, Candida albicans, and some bacteria.

Parimycin: isolation and structure elucidation of a novel cytotoxic 2,3-dihydroquinizarin analogue of gamma-indomycinone from a marine streptomycete isolate.

In our screening of actinomycetes from the marine environment for bioactive components, a new antibiotic with a novel structure designated as parimycin was obtained from the culture broth of Streptomyces sp. isolate B8652. The structure of the new antibiotic was determined by spectroscopic methods and by comparison of the NMR data with those of the structurally related gamma-indomycinone.

Chalcomycin B, a new macrolide antibiotic from the marine isolate Streptomyces sp. B7064.

In our screening of marine streptomycete isolates for bioactive components, a new macrolide antibiotic designated as chalcomycin B (1b) was isolated from the culture broth of a marine Streptomycete isolate B7064 together with chalcomycin (1a) as the active principles. The structure of the new antibiotic was determined by EI and ESI MS, 1H, 13C and 2D NMR spectroscopy and by comparison of the NMR data with those of chalcomycin.