Development of an extraction method for mycobacterial metabolome analysis.

As a prerequisite for studying the intracellular metabolome of mycobacteria, several methods were evaluated for efficient breakage of the cell using Mycobacterium bovis (BCG) as a model microorganism. Several pulping methods, treating with an Ultra-Turax, deep-freezing in liquid nitrogen followed by mechanical grinding, sonicating with probe head or cup horn and bead beating prior to solvent extraction were applied and compared. Gravimetry, electron microscopy, and nuclear magnetic resonance spectrometry were used to analyze the extracts. All analytical methods prove that sonicating is superior to mechanical grinding of deep-frozen cells. Two methods indicated that sonicating with a probe head enhances the efficiency of cell disruption compared to sonicating with a cup horn. The highest extract yield and chemical diversity were achieved by a combination of mechanical grinding and sonicating. Within the scope of a metabolomic analysis, the method of choice to treat mycobacterial cells is a combination of deep-freezing in liquid nitrogen and mechanical grinding followed by sonicating with a probe head.

Two novel cyclic peptides with antifungal activity from the cyanobacterium Tolypothrix byssoidea (EAWAG 195).

Two novel cyclic tridecapeptides, tolybyssidins A (1) and B (2), were isolated from the culture medium of mass cultured cyanobacterium Tolypothrix byssoidea (EAWAG 195) by means of bioguided isolation. The gross structures of these peptides were determined by 1D and 2D NMR experiments and tandem mass spectrometry. Both peptides contain the nonnatural amino acid dehydrohomoalanine (Dhha) as well as proteinogenic amino acids albeit with D- or L-configuration. The compounds exhibit moderate antifungal activity against the yeast Candida albicans.

New antibacterial metabolites from the cyanobacterium Nostoc commune(EAWAG 122b).

Two new compounds, a diterpenoid and an anthraquinone, as well as an indane derivative, which is reported as a natural product for the first time, have been isolated from the cells of the cultured cyanobacterium Nostoc commune (EAWAG 122b) by means of bioguided isolation. The structures were determined by spectroscopic methods, mainly NMR, infrared spectroscopy, and mass spectrometry. All isolates exhibit antibacterial activity.

Novel extracellular diterpenoids with biological activity from the cyanobacterium Nostoc commune.

Five novel extracellular metabolites with an unprecedented diterpenoid skeleton, 5-[(5-carboxy-2-hydroxy)benzyl]-11-hydroxymethyl-2,5,6,8a, 11-pentamethyldodecahydrocyclopentanaphthalene (1), 5-[(5-carboxy-2-hydroxy)benzyl]-11-formyl-2,5,6,8a, 11-pentamethyl-dodecahydrocyclopentanaphthalene (2), 5-[(5-carboxy-2-hydroxy)benzyl]-11-carboxy-2,5,6,8a, 11-pentamethyl-dodecahydrocyclopentanaphthalene (3), 5-[(5-carboxy-2-hydroxy)benzyl]-11-dihydroxymethyl-2,5,6,8a, 11-pentamethyldodecahydrocyclopentanaphthalene (4), and 5-[(5-carboxy-2-hydroxy)benzyl]-11-acetyl-2,5,6, 8a-tetramethyldodecahydrocyclopentanaphthalene (5), have been isolated from the culture medium of the terrestrial cyanobacterium Nostoc commune by means of bioguided isolation. The molecules were designated as comnostins A-E. The structures were determined by spectroscopic methods, mainly NMR and mass spectrometry. The relative stereochemistry of comnostin A was confirmed by single-crystal X-ray structure analysis. All comnostins showed antibacterial activities. Additionally, cytotoxic and molluscicidal activities were found for comnostin B.

A novel extracellular diterpenoid with antibacterial activity from the cyanobacterium Nostoc commune.

A novel extracellular metabolite with an unprecedented diterpenoid skeleton, 8-[(5-carboxy-2-hydroxy)benzyl]-2-hydroxy-1,1,4a,7, 8-pentamethyl-1,2,3,4,4a,6,7,8,8a,9,10,10a-dodecahydrophenanthrene , has been isolated from the culture medium of the terrestrial cyanobacterium Nostoc commune Vaucher (EAWAG 122b) by means of bioguided isolation. The molecule was designated as noscomin. The structure was determined by spectroscopic methods, mainly NMR and mass spectrometry. Noscomin exhibited antibacterial activity against Bacillus cereus, Staphylococcus epidermidis, and Escherichia coli.

Multiple screening of medicinal plants from Oaxaca, Mexico: ethnobotany and bioassays as a basis for phytochemical investigation.

Based on ethnobotanical data collected among Zapotec Indians in Mexico, nine species traditionally applied to treat skin diseases and two species used to treat gastrointestinal disorders were subjected to several bioassays as further selection criteria for phytochemical investigation. Ten were active against at least one of the pathogenic and/or non-pathogenic bacteria and one against a non-pathogenic fungus in bioautographic TLC and agar diffusion tests. Cytotoxic/antitumor potential was found for one plant species with cell lines (KB, Caco-2) and for six with the brine shrimp assay. In the NF-κB- and the HET-CAM-test used to test for anti-inflammatory potential, two respectively one plant extract showed noteworthy activity. Furthermore, a potentially immunomodulating activity was investigated by evaluating the influence of extracts in various in vitro assays using murine and human lymphoid cells. In addition to the reported biological activities of the eleven plant species, comparisons of the ethnobotanical data and strategies for the selection for further phytochemical investigations are discussed.