Purification and structure elucidation of three naturally bioactive molecules from the new terrestrial Streptomyces sp. TN17 strain

Thirty litres of fermentation broth was extracted from the newly isolated Streptomyces sp. strain TN17 and various separation and purification steps led to the isolation of three pure bioactive compounds (1-3). Compound 1: cyclo (L-Leu-L-Arg), a diketopiperazine 'DKP' derivative; 2: di-(2-ethylhexyl) phthalate, a phthalate derivative; and 3: cyclo 1-[2-(cyclopentanecarbonyl-3-phenyl-propionyl]-pyrrolidine-2-carboxylic acid (1-carbamoyl-propyl)-amide, a cyclic tetrapeptide derivative. The chemical structure of these three active compounds was established on the basis of spectroscopic studies (MS and NMR) and by comparison with data from the literature. According to our biological studies, the pure compounds (1-3) possess antibacterial and antifungal activities.     

Bioactive isocoumarins from a terrestrial Streptomyces sp. ANK302

Four isocoumarins have been isolated from the terrestrial Streptomyces sp. ANK302, namely 6,8-dimethoxy-3-methylisocoumarin (1), 6,8-dihydroxy-3-methylisocoumarin (2), 6,8-dihydroxy-7-methoxy-3-methylisocoumarin (3), and 6,7,8-trimethoxy-3-methylisocoumarin (4). Compound 1 is a new naturally-occurring isocoumarin, and 2 was isolated as a new bacterial product. The structures 1-4 were deduced from high resolution mass, 1D and 2D NMR spectra and by comparison with related compounds from the literature. Compound 2 showed a strong zoosporicidal activity at a concentration of 5 microg/mL against a phytopathogenic oomycete, Plasmopara viticola, and 1 was active against     

Isolation and structure elucidation of Chlorofusin, a novel p53-MDM2 antagonist from a Fusarium sp.

Wild-type p53 plays a crucial role in the prevention of cancer. Since dysfunction of p53 can be caused by increased levels of the protein MDM2, small molecules which antagonize the interaction between these two proteins have potential in cancer therapy. The discovery and structure determination of a fungal metabolite, chlorofusin, which antagonizes the p53/MDM2 interaction are reported.     

Benhamycin, novel alkaloid from terrestrial Streptomyces sp

During our screening for bioactive natural compounds from microorganisms, a novel alkaloid has been isolated from a terrestrial Streptomyces sp. isolate NR12, and named as benhamycin (1). This was along with the known metabolites, uracil, thymine, p-hydroxybenzoic acid, 2'-deoxyuridin, tryptophol, indolyl-3-carboxylic acid, and indolyl-3-carbaldehyde. Chemical structure of the novel compound was determined by detailed analysis of its spectroscopic data (extensive NMR experiments, 1 & 2D, MS spectroscopy, and MS high resolution). Structurally, Benhamycin (1) is a pentacyclic aromatic compound bearing an acridine moiety lactamized with benzene. Biological studies showed that the strain extract was moderately active against Gram-positive, Gram-negative bacteria and fungi.     

红树林植物角果木内生真菌次级代谢产物的分离鉴定

研究红树林植物角果木根部内生真菌Fusarium sp.JG13次级代谢产物。用硅胶柱层析、制备薄层层析和重结晶等方法,从该菌发酵液的乙酸乙酯萃取相中分离获得4个单体化合物,以及一对顺反异构体。运用现代波谱技术以及文献数据对照,鉴定其结构分别为physcion(1)、trans physcion bianthrone(2)、cis physcion bianthrone(3)、asperflavin(4)、neoechinulin A(5)和isodihydroauroglaucin(6)。所有化合物均为首次从角果木根内生真菌Fusarium sp.JG13发酵分离得到。     

Spirodionic acid, a novel metabolite from Streptomyces sp., part 1: structure elucidation and Diels-Alder-type biosynthesis

Spirodionic acid (1), a novel microbial metabolite with a spiro[4.5]decene skeleton, the 6-ethyl-2H-pyrone 5, dihydrosarkomycin (6), and other metabolites were isolated from the strain Streptomyces sp. Tü 6077. Structural elucidation was accomplished by NMR spectroscopic and mass-spectrometric studies, and the biosyntheses of compounds 1, 5, and 6 were investigated by feeding experiments with (13)C-labeled precursors. All results indicate a biogenetic sequence with metabolite 5 and sarkomycin (7) as precursors in the formation of spirocyclus 1 through an intermolecular Diels-Alder-type reaction.     

Structure elucidation of four prenylindole derivatives from Streptomyces sp. isolated from Ailuropoda melanoleuca feces

Four new prenylindole derivatives, (R)‐6‐(2,3‐dihydroxy‐3‐methylbutyl)indole (1), (R)‐6‐(2,3‐dihydroxy‐3‐methylbutyl)indolin‐2‐one (2), and an unseparated mixture of (Z)‐6‐(4‐hydroxy‐3‐methylbut‐2‐en‐1‐yl)indolin‐2‐one (3a) and (E)‐6‐(4‐hydroxy‐3‐methylbut‐2‐en‐1‐yl)indolin‐2‐one (3b) with a ratio of 3 : 2, were isolated from the culture broth of a streptomycete isolated from Ailuropoda melanoleuca feces. Their structures were elucidated on the basis of 1D and 2D NMR spectroscopic techniques. The absolute configuration of 1 was determined by Mosher's method. Copyright © 2013 John Wiley & Sons, Ltd.     

Isolation and structure elucidation of ovalicin

The structure of ovalicin, a metabolite of the fungus Pseudeurotium ovalis with immunosuppressive activity, has been determined to be 11 .     

Isolation and Identification of Pentalenolactone Analogs from Streptomyces sp. NRRL S-4

Terpene synthases are widely distributed in Actinobacteria. Genome sequencing of Streptomyces sp. NRRL S-4 uncovered a biosynthetic gene cluster (BGC) that putatively synthesizes pentalenolactone type terpenes. Guided by genomic information, the S-4 strain was chemically investigated, resulting in the isolation of two new sesquiterpenoids, 1-deoxy-8α-hydroxypentalenic acid (1) and 1-deoxy-9β-hydroxy-11-oxopentalenic acid (2), as shunt metabolites of the pentalenolactone (3) biosynthesis pathway. Their structures and absolute configurations were elucidated by analyses of HRESIMS and NMR spectroscopic data as well as time-dependent density functional theory/electronic circular dichroism (TDDFT/ECD) calculations. Compounds 1 and 2 exhibited moderate antimicrobial activities against Gram-positive and Gram-negative bacteria. These results confirmed that the pentalenolactone pathway was functional in this organism and will facilitate efforts for exploring Actinobacteria using further genome mining strategies.     

Isolation and elucidation of the structure of homocryptolepinone

The structure of a new indolobenzazepine alkaloid, homocryptolepinone, isolated from extracts of the roots of the indigenous Ghanaian medicinal plant Cryptolepis sanguinolenta, is reported. The structure was determined using mass spectrometric, one-dimensional nOe difference nmr, and inverse-detected two-dimensional nmr experiments which included HMQC, IDR-(Inverted Direct Response)-HMQC-TOCSY, and HMBC experiments. The structure of homocryptolepinone is significant in that it may provide insight into the biogenesis of the benzpyrrolizinobenzazepine portion of the structure of the complex spiro nona-cyclic alkaloid cryptospirolepine previously isolated in these laboratories from C. sanguinolenta, and which has no precedent in alkaloid chemistry.     

Isolation and structure elucidation of 11-desacetoxywortmannin

The structure of 11-desacetoxy-wortmannin ( 3 ), a new antiinflammatory metabolite of the fungus Penicillium funiculosum THOM, has been elucidated by physico-chemical methods and chemical correlation with wortmannin ( 1 ).     

Tumescenamide C,an antimicrobial cyclic lipodepsipeptide from Streptomyces sp.

Tumescenamide C, a new cyclic lipodepsipeptide, was isolated from a culture broth of an actinomycete Streptomyces sp. KUSC_F05. Tumescenamide C was a congener of tumescenamides A and B, representing a sixteen-membered ring system, consisting of two proteinogenic and three non-proteinogenic amino acids, to which a methyl-branched fatty acid was attached. The planar structure was determined by spectroscopic analysis, while its absolute stereochemistry was determined by chemical degradation and asymmetric synthesis. Tumescenamide C exhibited antimicrobial activity with high selectivity against Streptomyces species.     

Isolation and structure elucidation of ishwarol B

Ishwarol B was isolated from the bark oil of Cedrelopsis grevei and its structure elucidated by 1D and 2D NMR spectroscopy.     

Isolation and structure elucidation of a novel yellow pigment from the marine bacterium Pseudoalteromonas tunicata

The marine environment is a major source for many novel natural compounds. A new yellow pigment has been isolated from the marine bacterium P. tunicata and identified as a new member of the tambjamine class of compounds. The structural identification was achieved by a combination of 1D and 2D-NMR spectroscopy and high resolution mass spectrometry data.     

Isolation and structure elucidation of a new prenylcoumarin from Murraya paniculata var. omphalocarpa (Rutaceae)

A new C-8 prenylated 5,7-dimethoxycoumarin named omphamurrayin was isolated from the leaves of Murraya paniculata var. omphalocarpa, and its structure was established as 5,7-dimethoxy-8-(1-oxo-2-senecioyl-3-methyl-3-butenyl)-2H-1-benzopyran-2-one on the basis of the spectroscopic evidence. The taxonomic status of M. paniculata var. omphalocarpa is briefly discussed, along with its synonymity to M. paniculata from the chemosystematic viewpoint.     

Elaiomycins B and C: alkylhydrazide antibiotics from Streptomyces sp. BK 190

Two novel alkyhydrazides, elaiomycins B and C, together with the azoxy antibiotic elaiomycin were isolated from Streptomyces sp. BK 190. The structures were established by 1D- and 2D-NMR spectroscopy including (15)N NMR studies and high-resolution orbitrap-ESI-mass spectrometry.     

Structural elucidation and NMR assignments of two new pyrrolosesquiterpenes from Streptomyces sp. Hd7‐21

Two new pyrrolosesquiterpenes were isolated from cultures of the soil actinomycete Streptomyces sp. Hd7‐21. The structures of these compounds were elucidated by extensive spectroscopic analyses including MS and 1D and 2D NMR data. Their cytotoxic activity against a panel of human cancer cell lines were biologically evaluated. Copyright © 2013 John Wiley & Sons, Ltd.     

Isolation and Characterization of Actinoramides A-C, Highly Modified Peptides from a Marine Streptomyces sp

Reported herein is the isolation and structure elucidation of three highly modified peptides, actinoramides A-C (1-3), which are produced by a marine bacterium closely related to the genus Streptomyces. The planar structures of the actinoramides, which are composed of the unusual amino acids 2-amino-4-ureidobutanoic acid and 4-amino-3-hydroxy-2-methyl-5-phenylpentanoic acid, were assigned by chemical transformations and by interpretation of spectroscopic data, while the absolute configuration of these new peptides were defined by application of the advanced Marfey’s and Mosher’s methods.