Purification and structure elucidation of the by-product of new regulator of antibiotic production and differentiation of Streptomyces.

Streptomyces globisporus 1912, a producer of the antitumor antibiotic landomycin E, forms the new low-molecular signaling molecule N-methylphenylalanyl-dehydrobutyrine diketopiperazine (BDD) and its complex and unstable by-product which restore, like the A-factor in Streptomyces griseus 773, landomycin E and streptomycin biosynthesis, and sporulation of the defective mutants S. globisporus 1912-B2 and S. griseus 1439, respectively. Here, we report the purification and structure elucidation of two compounds with R(f)0.8 by HPLC, LC/MS and 1HMR analysis. These compounds have m/z 338 and 384, accordingly, and each of them is presented by two stereoisomers containing BDD in their structure. A hypothesis explaining the composition and regulatory properties of these unstable compounds is presented.

Bromoanaindolone, a novel antimicrobial exometabolite from the cyanobacterium Anabaena constricta.

A new brominated indole alkaloid, designated as bromoanaindolone, was isolated from culture media of the cyanobacterium Anabaena constricta and was identified as 6-bromo-3-hydroxy-3-methyl-indol-2-one with a slight excess of the (3R) enantiomer. The molecular structure was elucidated on the basis of IR, MS and NMR data. This extracellular metabolite of A. constricta possessed antimicrobial (anticyanobacterial and antibacterial) activity in different test systems, such as suspension and porous matrix tests.

Halichondria sulfonic acid, a new HIV-1 inhibitory guanidino-sulfonic acid, and halistanol sulfate isolated from the marine sponge Halichondria rugosa Ridley & Dendy.

A new sulfur-containing guanidino derivative, halichondria sulfonic acid (1) showing anti-HIV-1 activity, and halistanol trisulfate (2) with anti-tumor activity have been isolated from the marine sponge Halichondria rugosa Ridley & Dendy collected in the Chinese Southern Sea. The structure of 1 was elucidated by analysis of spectroscopic and crystal data.

Sesquiterpene lactones from Crepis cameroonica (Asteraceae).

In addition to one known compound, 3beta,8alpha-dihydroxyguaian-4(15),10(14),11(13)-trien-6,12 olide (8-desacylcynaropicrin) (3), two new sesquiterpene lactones have been isolated from the aerial parts of Crepis cameroonica. By means of spectroscopic analysis, the structures and relative configurations of the new compounds were established as 3beta,9beta-dihydroxyguaian-4(15),10(14),11(13)-trien-6,12 olide (1) and 8alpha-hydroxy-4alpha(13),11beta(15)-tetrahydrozaluzanin C (2). The in vitro antimicrobial spectrum of pure compounds and crude extracts are also reported.

Controlling production of brominated cyclic depsipeptides by Pseudoalteromonas maricaloris KMM 636T.

AIMS: This study aims at evaluating the impact of the nutrient medium components on the in vitro production of the cytotoxic alterochromides. METHODS AND RESULTS: The employment matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) facilitated the identification of a range of brominated cyclic depsipeptides with molecular masses of 843/845, 857/859 and 922/924/926 Da, and 936/938/940 Da produced by the marine bacterium Pseudoalteromonas maricaloris KMM 636T. The fractions of cytotoxic yellow pigments yielded after methanol extraction of P. maricaloris KMM 636T cells grown on five nutrient media were solely composed of brominated cyclic depsipeptides. Bromo-alterochromides A and B were obtained after cultivation on low nutrient media, while dibrominated derivatives were the principal components of the biosynthesis during cultivation on nutrient rich media. CONCLUSIONS: The quantity of bromo-alterochromides and their dibromo- derivates varied depending on the media composition. SIGNIFICANCE AND IMPACT OF THE STUDY: MALDI-TOF mass spectrometry enables to generate accurate mass analysis for the identification of peptide and its derivates which is important in controlling the production of biologically active compounds in vitro.

Isolation and structure elucidation of diazaquinomycin C from a terrestrial Streptomyces sp. and confirmation of the akashin structure.

In the screening of terrestrial Streptomycetes for bioactive components, a new antibiotic designated as diazaquinomycin C (2b) was isolated. The new antibiotic was found to be a homologue of diazaquinomycin A (2a) by spectroscopic methods and by comparison of the NMR data with those of 2a. The same strain additionally produced the akashins 1a-1c. The configuration of the N-O acetale bond in these rare glycosylated dichloroindigo derivatives was confirmed to be beta.

The separation of hypericine and pseudohypericine from Hypericum perforatum L.

The extraction of Hypericum perforatum L. was carried out by the method of ultrasonic maceration. The separation of H. perforatum L. extract in order to obtain hypericine and pseudohypericine rich fractions was carried out by the following chromatographic methods: flash column chromatography, high speed countercurrent chromatography, XAD solid phase extraction and Sephadex column chromatography. The separation by the Sephadex column chromatography gave the best results. Preparative HPLC was used to isolate hypericine and pseudohypericine from fraction 4 obtained by the Sephadex column chromatography procedure.

A short and efficient transformation of rhamnose into activated daunosamine, acosamine, ristosamine and epi-daunosamine derivatives, and synthesis of an anthracycline antibiotic acosaminyl-epsilon-iso-rhodomycinone.

3-Amino-2,3,6-trideoxyhexopyranoses are essential constituents of most anthracycline antitumour antibiotics. For an investigation of structure-activity relationships, the four diastereomeric amino sugars daunosamine, acosamine, ristosamine, and epi-daunosamine were synthesised in short and efficient routes starting from commercially available rhamnose. Several glycosyl donors were provided and their use was exemplified in the synthesis of acosaminyl-epsilon-isorhodomycinone.

In vitro leishmanicidal activity of monomeric and dimeric naphthoquinones.

A series of monomeric and dimeric naphthoquinones with potential for treatment of Leishmania infections was identified in vitro using both a direct cytotoxicity assay against extracellular promastigotes of Leishmania donovani, L. infantum, L. enriettii, and L. major and a test against intracellular amastigote L. donovani residing within murine macrophages. Several naphthoquinones proved to be active at concentrations in the microgram range (EC(50) 0.9-17.0 microg/ml). When tested against a panel of human cancer cell lines (KB, SKMel, A549, MDA) and murine bone marrow culture-derived macrophages (BMMPhi) as mammalian host cell controls, compounds with anti-Leishmania-activity showed moderate (EC(50)>25 microg/ml) to pronounced (EC(50)<10 microg/ml) toxic effects.

A rare prostaglandin from the soft coral Sarcophyton crassocaule of the Indian Ocean.

The rare prostaglandin methyl (5Z)-9,15-dioxoprosta-5, 8(12)-dien-1-oate (1), hitherto unreported as a natural product, has been isolated from the Indian Ocean soft coral Sarcophyton crassocaule. Its structure was elucidated using detailed spectral ((1)H and (13)C NMR, DEPT, H-H COSY, C-H COSY, HRMS, and HMBC) analysis.

New butenolides from two marine streptomycetes.

Chemical examination of two marine Streptomycetes has resulted in the isolation of four new butenolides, namely 4, 10-dihydroxy-10-methyl-dodec-2-en-1,4-olide (1), two diastereomeric 4,11-dihydroxy-10-methyl-dodec-2-en-1,4-olides (2/3), and 4-hydroxy-10-methyl-11-oxo-dodec-2-en-1,4-olide (4). The structures were identified by interpretation of the 2D NMR and mass spectral data.

Triterpenoids, essential oil and photo-oxidative 28 --> 13-lactonization of oleanolic acid from Lantana camara.

Two novel triterpenoids have been isolated from the roots of Lantana camara L.: 3beta,19alpha dihydroxy ursan-28-oic acid and 21,22beta-epoxy-3beta-hydroxy olean-12-en-28-oic acid in its methyl ester form. Its leaves have yielded an essential oil which is rich in sesquiterpenes. Oleanolic acid, which is thought to be a hepatoprotective compound, was isolated from L. camara roots and converted into its 28 --> 13beta lactone by a facile photo-oxidation reaction.

In vitro leishmanicidal activity of monomeric and dimeric naphthoquinones.

A series of monomeric and dimeric naphthoquinones with potential for treatment of Leishmania infections was identified in vitro using both a direct cytotoxicity assay against extracellular promastigotes of Leishmania donovani, Leishmania infanturn, Leishmania enriettii, and Leishmania major and a test against intracellular amastigote L. donovani residing within murine macrophages. Several naphthoquinones proved to be active at concentrations in the microgram range (EC(50) 0.9-17.0 microg/ml). When tested against a panel of human cancer cell lines (KB, SKMel, A549, MDA) and murine bone marrow culture-derived macrophages (BMMPhi) as mammalian host cell controls, compounds with anti-Leishmania-activity showed moderate (EC(50)>25 microg/ml) to pronounced (EC(50)<10 microg/ml) toxic effects.

Demethyl mutactimycins, new anthracycline antibiotics from Nocardia and Streptomyces strains.

New anthracycline antibiotics 3'-O-demethyl mutactimycin (3) and 4-O,3'-O-didemethyl mutactimycin (4) were isolated from two actinomycetes strains, Nocardia transvalensis and Streptomyces sp. GW 60/1571. The chemical structures were elucidated by mass spectrometry and NMR spectroscopy. Antibiotic 3 displayed moderate antimicrobial activity against Gram-positive bacteria and cytotoxicity against P388, L1210 and HeLa tumor cells (IC50; 9.6, >25 and 20 microg/ml, respectively).

Carbazole antibiotics synthesis in a Streptomyces tendae bald mutant, created by acriflavine treatment.

Acriflavine treatment on Streptomyces tendae generated a bald mutant (bld-1) with an altered antibiotic pattern. The parental strain produced nikkomycins and juglomycins, whereas the mutant bld-1 was only capable of juglomycin synthesis. The existence of a mutant defective in morphogenesis and in nikkomycin biosynthesis suggests a common regulation of these processes. An interesting finding of this study is that mutant bld-1 produced two carbazole derivatives, hitherto never seen in cultures of the parental strain. It seems likely that the DNA intercalating dye acriflavine, by mutagenesis, had activated cryptic genes which are involved in carbazole synthesis. The two carbazole derivatives were identified as the neuronal cell protecting compounds CS-79B and carquinostatin A, recently isolated from a wild-type of S. exfoliatus. We found that both substances showed antibacterial activity.

Anthranilamides: new antimicroalgal active substances from a marine Streptomyces sp.

2-[Methyl-(3-phenylpropionyl)amino]-benzoic acid (1e) was isolated from a culture of marine Streptomyces sp. strain B7747. Analogous compounds have potential importance as phytotoxic substances, hence compound 1e and the analogues 1a approximately 1d and 1f approximately 3a were synthesised. Antimicroalgal activity of the anthranilamide analogues showed that esters 1b, 1f and 2b were more active than the free acids. The minimum inhibitory concentration (MIC) against Chlorella vulgaris, Chlorella sorokiniana, Chlorella salina and Scenedesmus subspicatus ranged from 20 to 107 micrograms/ml. All anthranilamides were inactive against Staphylococcus aureus, Escherichia coli, and Mucor miehei.

Comparison of the lethal effects of different actinomycins on a repair-deficient strain of Escherichia coli.

We report here the isolation and purification of a genotoxic antibiotic from the culture medium of a Streptomyces strain. The antibiotic was identified as actinomycin X2 by using a database search (AntiBase). In the previous studies a related compound, actinomycin D, has been shown to be non-mutagenic in the salmonella/microsome assay and several other bacterial systems. The fact that an actinomycin was detected by a bacterial repair assay seems to contradict these results. Therefore we tested several actinomycins by differential killing assay based on the same Escherichia coli strains that were used in our screening bioassays. According to our results the uvrA, recA double mutant sensitizes E. coli to the genotoxic effects of actinomycins.

Dihydrophencomycin methyl ester, a new phenazine derivative from a marine Streptomycete.

The novel 5,10-dihydrophencomycin methyl ester (4) and the known microbial metabolites (2-hydroxyphenyl)-acetamide (1), menaquinone MK9 (II, III, VIII, IX-H8) (2), and phencomycin (3a) were isolated from an unidentified marine Streptomyces sp. and the structures were elucidated by NMR methods. Compound 4 shows weak antibiotic activity against Escherichia coli and Bacillus subtilis.