Synergistic action between peptide-neomycin conjugates and polymyxin B against multidrug-resistant gram-negative pathogens.

Globally, it is predicted that by 2050, 10 million people will die annually because of infections with drug-resistant bacteria. Since antibacterial agents with novel mechanisms of action have not been developed in the past 30 years, there has been a surge of interest in combination therapies using existing drugs. The combination of aminoglycosides and colistin is often used to treat pneumonia caused by multidrug-resistant bacteria.

Nucleic Acid Specificity, Cellular Localization and Reduced Toxicities of Thiazole Orange-Neomycin Conjugates.

Selective binding of small molecule ligands to nucleic acids with high affinity and limited toxicity remains an important goal in the development of compounds that can probe DNA or RNA in cells. Thiazole orange is a cell semi-permeant, fluorescent cyanine dye, with low background noise, that binds several forms of nucleic acids. However, thiazole orange can exhibit cytotoxicity when used at high concentration and/or with prolonged exposure.

Anti-Inflammatory Activity of Glycolipids and a Polyunsaturated Fatty Acid Methyl Ester Isolated from the Marine Dinoflagellate .

A new monogalactosyldiacylglycerol (MGDG), a known monogalactosylmonoacylglycerol (MGMG) and a known polyunsaturated fatty acid methyl ester (PUFAME) were isolated from the marine dinoflagellate . The planar structure of the glycolipids was elucidated using mass spectroscopy (MS) and nuclear magnetic resonance (NMR) analyses and comparisons to the known glycolipid to confirm its structure. The MGDG was characterized as 3---D-galactopyranosyl-1--3,6,9,12,15-octadecapentaenoyl-2--tetradecanoylglycerol .

Gentiopicroside isolated from Gentiana scabra Bge. inhibits adipogenesis in 3T3-L1 cells and reduces body weight in diet-induced obese mice.

Gentiopicroside is a major active component of the Gentiana scabra Bge., which is commonly used as herbal medicine for the treatment of inflammation in Asia. Gentiopicroside significantly down-regulated expression of key adipogenic transcription factors (PPARγ, C/EBPα, SREBP-1c) and dose-dependently inhibited the lipid uptake-related gene (LPL), fatty acid transport-related gene (FABP4) and triglyceride (TG) synthesis-related gene (DGAT2), as well as fatty acid synthesis-related genes (FAS, SCD1), which resulted in reduced intracellular lipid droplet accumulation and TG content in 3T3-L1 cells.

Antartin, a Cytotoxic Zizaane-Type Sesquiterpenoid from a sp. Isolated from an Antarctic Marine Sediment.

Antartin (), a new zizaane-type sesquiterpene, was isolated from sp. SCO736. The chemical structure of was assigned from the interpretation of 1D and 2D NMR in addition to mass spectrometric data.

Fluvirucin B6, a new macrolactam isolated from a marine-derived actinomycete of the genus Nocardiopsis.

A new 14-membered macrolactam natural product, fluvirucin B6 (1), was isolated from a marine-derived actinomycete, Nocardiopsis sp. CNQ-115, via HPLC-UV guided isolation. The chemical structure of 1 was elucidated by 1D and 2D NMR spectroscopic data analysis.

Anti-Pigmentary Effect of (-)-4-Hydroxysattabacin from the Marine-Derived Bacterium Bacillus sp.

Bioactivity-guided isolation of a crude extract from a culture broth of Bacillus sp. has led to the isolation of (-)-4-hydroxysattabacin (1). The inhibitory effect of (-)-4-hydroxysattabacin (1) was investigated on melanogenesis in the murine melanoma cell line, B16F10, and human melanoma cell line, MNT-1, as well as a pigmented 3D-human skin model.

Diacetoxyscirpenol as a new anticancer agent to target hypoxia-inducible factor 1.

Hypoxia activates hypoxia-inducible factor 1, which promotes the progression of malignancy by stimulating angiogenesis and by augmenting the ability of tumors to survive. Thus, HIF-1 is one of the most compelling targets for treating cancers. The aim of this study was to find a small molecule that inhibits HIF-1 under hypoxia in cancer cells.

Induced production of 6,9-dibromoflavasperone, a new radical scavenging naphthopyranone in the marine-mudflat-derived fungus Aspergillus niger.

The addition of metal bromides (NaBr and CaBr2) during fermentation of the marine-mudflat-derived fungus Aspergillus niger induced production of a new radical scavenging brominated naphthopyranone, 6,9-dibromoflavasperone (1); and three known naphtho-γ-pyranone monomers, flavasperone (2), TMC-256A1 (3), and fonsecin (4); and one naphtho-γ-pyranone dimer, aurasperone B (5). The structure of 6,9-dibromoflavasperone (1) was assigned through the combination of spectroscopic data analyses and comparison with the spectral data of flavasperone (2). Compounds 1-5 displayed potent radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl, with IC50 values of 21, 25, 0.

Cristazine, a New Cytotoxic Dioxopiperazine Alkaloid from the Mudflat-Sediment-Derived Fungus Chaetomium cristatum.

Cristazine (1), a new class of dioxopiperazine alkaloid, along with previously isolated chetomin (2), neoechinulin A (3), and golmaenone (4), were isolated from the mudflat-sediment-derived fungus Chaetomium cristatum. The structure and absolute stereochemistry of 1 was assigned on the basis of NMR, electron impact (EI)-MS, tandem FAB-MS/MS, and circular dichroism (CD) experiments. Compounds 1-4 displayed potent radical-scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH), with IC50 values of 19, 15, 24, and 20 µM, respectively, which were similar to that of the positive control, ascorbic acid (IC50, 20 µM).

Nocarimidazoles A and B from a Marine-Derived Actinomycete of the Genus Nocardiopsis.

Chemical investigation of a marine-derived actinomycete isolated from marine sediments collected off the coast of southern California and identified as a Nocardiopsis sp. (strain CNQ115) led to the isolation of two new 4-aminoimidazole alkaloids, nocarimidazoles A (1) and B (2). The chemical structures of nocarimidazoles A and B were assigned by interpretation of NMR spectroscopic data and through methylation to yield monomethyl and dimethyl derivatives.

The Inhibitory Effect of Alisol A 24-Acetate from Alisma canaliculatum on Osteoclastogenesis.

Osteoporosis is a disease that decreases bone mass. The number of patients with osteoporosis has been increasing, including an increase in patients with bone fractures, which lead to higher medical costs. Osteoporosis treatment is all-important in preventing bone loss.

Induced production of methyl bromodihydroxyphenyl acetates by the marine-derived fungus Aspergillus sp.

The addition of metal bromides (NaBr and CaBr2) during fermentation of a marine isolate of the fungus Aspergillus sp. induced production of two new brominated dihydroxyphenylacetic acid derivatives, methyl 2-(6-bromo-3,4-dihydroxyphenyl)acetate (1) and methyl 2-(2,5-dibromo-3,4-dihydroxyphenyl)acetate (2), and a known compound, 2-(3,4-dihydroxyphenyl)acetic acid (3). The structures of the two new compounds (1, 2) were assigned through the combination of spectroscopic data analyses and comparison with the spectral data of compound 3.

New production of 5-bromotoluhydroquinone and 4-O-methyltoluhydroquinone from the marine-derived fungus Dothideomycete sp.

The addition of NaBr to the fermentation medium of a marine isolate of the fungus Dothideomycete sp. resulted in induced production of two toluhydroquinone derivatives, 5- bromotoluhydroquinone (1) and 4-O-methyltoluhydroquinone (2), and two known compounds, toluhydroquinone (3) and gentisyl alcohol (4). The structures of 1 and 2 were assigned through the spectroscopic data analyses.

Flavusides A and B, antibacterial cerebrosides from the marine-derived fungus Aspergillus flavus.

Flavusides A (1) and B (2), two new antibacterial cerebroside derivatives, and the previously described phomaligol A (3), kojic acid (4), methyl kojic acid (5), and dimethyl kojic acid (6) have been isolated from the extract of a marine isolate of the fungus Aspergillus flavus. The structure and absolute stereochemistry of two cerebrosides were assigned on the basis of NMR and Tandem FAB-MS/MS experiments. Compounds 1, 2, and 3 exhibited a mild antibacterial activity against Staphylococcus aureus, methicillin-resistant S.

Microbial transformation of a monoterpene, geraniol, by the marine-derived fungus Hypocrea sp.

Geraniol (1) is the biogenetic precursor of a number of monoterpenes. We tested various marine-derived microorganisms to determine their ability to biotransform 1. Only Hypocrea sp.