ABSTRACT
A new diketopiperazine (DKP) derivative, (6R,3Z)-3-benzylidene-6-isobutyl-1-methyl piperazine-2,5-dione (1), as well as five known DKPs 2-6 was isolated from a deep sea-derived Streptomyces sp. SCSIO 04496. The structure of 1 was elucidated using a combination of 1D and 2D NMR, HR-ESI-MS and chiral-phase HPLC techniques. Compounds 1-6 did not show cytotoxic activity at a concentration of 100 µM in bioactivity assay.
Subject(s)
Benzylidene Compounds/chemistry , Benzylidene Compounds/pharmacology , Diketopiperazines/chemistry , Piperazines/chemistry , Piperazines/pharmacology , Streptomyces/chemistry , Benzylidene Compounds/isolation & purification , Cell Line, Tumor/drug effects , Chromatography, High Pressure Liquid , Diketopiperazines/pharmacology , Drug Screening Assays, Antitumor , Humans , Magnetic Resonance Spectroscopy , Molecular Structure , Oceans and Seas , Piperazines/isolation & purification , Spectrometry, Mass, Electrospray Ionization , Streptomyces/isolation & purification , Water MicrobiologyABSTRACT
Microbial transformation of xanthohumol isolated from agro-residue (spent hops), by Aspergillus ochraceus was investigated. A new aurone, (Z)-2â³-(2â´-hydroxyisopropyl)-dihydrofurano[4â³,5â³:6,7]-3',4'-dihydroxy-4-methoxyaurone, was obtained as a main transformation product. Three minor metabolites were identified as 2â³-(2â´-hydroxyisopropyl)-dihydrofurano[4â³,5â³:3',4']-2',4-dihydroxy-6'-methoxychalcone, (2S,2â³S)-2â³-(2â´-hydroxyisopropyl)-dihydrofurano[4â³,5â³:7,8]-4'-hydroxy-5-methoxyflavanone and (2S,2â³R)-2â³-(2â´-hydroxyisopropyl)-dihydrofurano[4â³,5â³:7,8]-4'-hydroxy-5-methoxyflavanone. Their structures were elucidated on the basis of spectroscopic evidences. The antioxidant properties of xanthohumol and its metabolites were investigated using the 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method. The major biotransformation product, was 8.6-fold stronger antioxidant than xanthohumol and 2.3-fold than ascorbic acid.
Subject(s)
Antioxidants/chemistry , Aspergillus ochraceus/metabolism , Benzofurans/isolation & purification , Benzylidene Compounds/isolation & purification , Flavonoids/chemistry , Propiophenones/chemistry , Antioxidants/metabolism , Biotransformation , Flavonoids/metabolism , Propiophenones/metabolismABSTRACT
Unlike their terrestrial counterparts, marine myxobacteria are hardly investigated for their secondary metabolites. This study describes three new compounds (1-3), named salimyxins and enhygrolides, obtained from the obligate marine myxobacterium Enhygromyxa salina. These are the first natural products obtained from Enhygromyxa species. Their structures were elucidated by spectroscopic analysis, including NMR and CD spectroscopy. Enhygrolides are closely related to the nostoclides, which were initially isolated from a cyanobacterium of the genus Nostoc. The salimyxins, representing structurally most unusual degraded sterols, are close to identical to demethylincisterol from the sponge Homaxinella sp. Salimyxin B and enhygrolide A inhibit the growth of the Gram-positive bacterium Arthrobacter cristallopoietes (MIC salimyxin B, 8 µg mL⻹; enhygrolide A, 4 µg mL⻹).
Subject(s)
4-Butyrolactone/analogs & derivatives , Anti-Bacterial Agents/chemistry , Benzylidene Compounds/chemistry , Diterpenes/chemistry , Myxococcales/metabolism , 4-Butyrolactone/chemistry , 4-Butyrolactone/isolation & purification , 4-Butyrolactone/pharmacology , Animals , Anti-Bacterial Agents/isolation & purification , Anti-Bacterial Agents/pharmacology , Arthrobacter/drug effects , Benzylidene Compounds/isolation & purification , Benzylidene Compounds/pharmacology , Diterpenes/isolation & purification , Diterpenes/pharmacology , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Magnetic Resonance Spectroscopy , Molecular Conformation , Myxococcales/classification , Phylogeny , Porifera/metabolismABSTRACT
Tris-aromatic furanones (1-4) and related bis-aromatic diesters (5 and 6) isolated from the dark red ascidian Synoicum sp., were evaluated for their inhibitory activities toward Candida albicans isocitrate lyase (ICL). These studies led to the identification of compounds 1, 3, and 4 as potent ICL inhibitors, with IC50 values of 7.62, 17.16, and 10.36 µM, respectively. Growth phenotype of ICL deletion mutants and Northern blot analysis data indicated that compound 1 inhibits the ICL expression in C. albicans under C2 carbon utilizing condition.
Subject(s)
4-Butyrolactone/analogs & derivatives , Antifungal Agents/chemistry , Benzylidene Compounds/chemistry , Candida albicans/enzymology , Fungal Proteins/antagonists & inhibitors , Isocitrate Lyase/antagonists & inhibitors , Phenols/chemistry , Urochordata/chemistry , 4-Butyrolactone/chemistry , 4-Butyrolactone/isolation & purification , 4-Butyrolactone/pharmacology , Animals , Antifungal Agents/isolation & purification , Antifungal Agents/pharmacology , Benzylidene Compounds/isolation & purification , Benzylidene Compounds/pharmacology , Candida albicans/drug effects , Fungal Proteins/genetics , Fungal Proteins/metabolism , Isocitrate Lyase/genetics , Isocitrate Lyase/metabolism , Mutation , Phenols/isolation & purification , Phenols/pharmacology , RNA, Messenger/metabolismABSTRACT
A new butenolide isoaspulvinone E (1), together with two known butenolides aspulvinone E (2) and pulvic acid (3) were isolated from the marine-derived fungus, Aspergillus terreus Gwq-48. They showed significant anti-influenza A H1N1 virus activities, with IC50 values of 32.3, 56.9, and 29.1µg/mL, respectively. Moreover, only compound 1 exhibited effective inhibitory activity against H1N1 viral neuraminidase (NA), and docking of two isomers (1-2) into the active sites of NA showed that the E double bond Δ(5(10)) was essential to achieve activity.
Subject(s)
4-Butyrolactone/analogs & derivatives , Antiviral Agents/chemistry , Aspergillus/metabolism , Benzylidene Compounds/chemistry , Influenza A Virus, H1N1 Subtype/metabolism , Neuraminidase/antagonists & inhibitors , 4-Butyrolactone/chemistry , 4-Butyrolactone/isolation & purification , 4-Butyrolactone/pharmacology , Animals , Antiviral Agents/isolation & purification , Antiviral Agents/pharmacology , Aspergillus/isolation & purification , Benzylidene Compounds/isolation & purification , Benzylidene Compounds/pharmacology , Binding Sites , Catalytic Domain , Cell Line , Cell Survival/drug effects , Dogs , Humans , Influenza A Virus, H1N1 Subtype/drug effects , Magnetic Resonance Spectroscopy , Molecular Conformation , Molecular Docking Simulation , Neuraminidase/metabolism , Rhizosphere , Soil MicrobiologyABSTRACT
Solvent-free Claisen-Schmidt reactions of cycloalkanones with various substituted benzaldehydes (aryl aldehydes) using solid NaOH (20 mol%) and applying a grinding technique were studied. Quantitative yields (96-98%) of α,α'-bis-(substituted-benzylidene)cycloalkanones were obtained. Aliphatic aldehydes also provided α,α'-bis-(substituted-alkylidene)cycloalkanones in very good yields with minor amounts of a-(substituted-alkylidene)cycloalkanones. The catalytic performance of solid NaOH was examined. The molar ratio of NaOH was optimized. The catalytic effect of solid NaOH was also evaluated by comparing it with KOH, NaOAc, and NH(4)OAc and it turns out that 20 mol% of solid NaOH was good enough to catalyze the Claisen-Schmidt reactions of cycloalkanones with various substituted benzaldehydes. Additionally, the regioselectivity of the Claisen-Schmidt reaction of acetone with benzaldehyde was examined. Using the same method, we could synthesize the corresponding bis-benzylidene- and mono-benzylideneacetone separately in 98% and 96% yields, respectively.
Subject(s)
Benzylidene Compounds/chemical synthesis , Cycloparaffins/chemical synthesis , Sodium Hydroxide/chemistry , Solid-Phase Synthesis Techniques , Acetates , Benzylidene Compounds/isolation & purification , Catalysis , Cycloparaffins/isolation & purification , Freezing , Hydroxides/chemistry , Potassium Compounds/chemistry , Sodium Acetate/chemistryABSTRACT
H(2)SO(4)-silica-promoted removal of benzylidene, isopropylidene, trityl and tert-butyldimethylsilyl groups from sugar derivatives was accomplished by following an 'on-column' protocol in a virtually waste-free condition.
Subject(s)
Alkenes/isolation & purification , Benzylidene Compounds/isolation & purification , Organosilicon Compounds/isolation & purification , Silicon Dioxide/chemistry , Sulfates/chemistry , Trityl Compounds/isolation & purification , Alkenes/chemistry , Benzylidene Compounds/chemistry , Hydrolysis , Molecular Structure , Organosilicon Compounds/chemistry , Trityl Compounds/chemistryABSTRACT
Four new C-glucopyranosides of resveratrol oligomers, hemsleyanosides A-D, were isolated from the bark of Shorea hemsleyana. The structures were established on the basis of spectroscopic evidence, including 1H-1H and 1H-13C long-range couplings and nuclear Overhauser effect experiments in the NMR spectrum.