Talarodrides A-F, Nonadrides from the Antarctic Sponge-Derived Fungus Talaromyces sp. HDN1820200.

Six new nonadride derivatives, named talarodrides A-F (1-6), were isolated from the Antarctic sponge-derived fungus Talaromyces sp. HDN1820200. All structures including the absolute configurations were deduced by extensive spectroscopic analysis and computational ECD calculations. Compounds 1-4 share a rare caged bicyclo[4.3.1]-deca-1,6-diene with a bridgehead olefin and maleic anhydride core skeleton, while compounds 5 and 6 possess the first case of a naturally occurring 5/7/6 methanocyclonona[c]furan skeleton. Talarodride A (1) and talarodride B (2) showed selective inhibitory effects against Proteus mirabilis and Vibrio parahemolyticus with MICs of 3.13-12.5 µM.

Study on the secondary metabolites of grasshopper-derived fungi Arthrinium sp. NF2410.

Two new 2-carboxymethyl-3-hexyl-maleic anhydride derivatives, arthrianhydride A (1) and B (2), along with three known compounds 3-5, were isolated from the fermentation broth of a grasshopper-associated fungus Arthrinium sp. NF2410. The structures of new compounds 1 and 2 were determined based on the analysis of the HR-ESI-MS and NMR spectroscopic data. Furthermore, compounds 1 and 2 were evaluated on inhibitory activity against the enzyme SHP2 and both of them showed moderate inhibitory activity against SHP2.

(-)-ß-Homoarginine anhydride, a new antioxidant and tyrosinase inhibitor, and further active components from Trichosanthes truncata.

One new amino acid derivative, (-)-ß-homoarginine anhydride 1, as well as nine known compounds were isolated from Trichosanthes truncata. The structures of the isolates were elucidated by spectroscopic methods. Among them, compounds 5 and 11 could notably dose-dependently inhibit ROS productions in HaCaT keratinocyte cells without cytotoxicity in the concentration range of 0.2-20 µM. In cell-free mushroom tyrosinase assay, compounds 1-5, 10 and 11 had more potential anti-tyrosinase activities with IC50 values of 106.9-255.6 µM than arbutin that were similar to predicted values of binding affinity calculated by molecule docking. The most active 2 had hydrogen bonds (Ser77, Glu309, Phe454) and electrostatic charges (Glu309, Glu248) interactions with mushroom tyrosinase, respectively. Our data manifested that T. truncata and its components are potentially to be developed as anti-aging and whitening agents for skin disorders.

Sensitivity of Neurospora crassa to a marine-derived Aspergillus tubingensis anhydride exhibiting antifungal activity that is mediated by the MAS1 protein.

The fungus Aspergillus tubingensis (strain OY907) was isolated from the Mediterranean marine sponge Ircinia variabilis. Extracellular extracts produced by this strain were found to inhibit the growth of several fungi. Among the secreted extract components, a novel anhydride metabolite, tubingenoic anhydride A (1) as well as the known 2-carboxymethyl-3-hexylmaleic acid anhydride, asperic acid, and campyrone A and C were purified and their structure elucidated. Compound 1 and 2-carboxymethyl-3-hexylmaleic acid anhydride inhibited Neurospora crassa growth (MIC = 330 and 207 µM, respectively) and affected hyphal morphology. We produced a N. crassa mutant exhibiting tolerance to 1 and found that a yet-uncharacterized gene, designated mas-1, whose product is a cytosolic protein, confers sensitivity to this compound. The ∆mas-1 strain showed increased tolerance to sublethal concentrations of the chitin synthase inhibitor polyoxin D, when compared to the wild type. In addition, the expression of chitin synthase genes was highly elevated in the ∆mas-1 strain, suggesting the gene product is involved in cell wall biosynthesis and the novel anhydride interferes with its function.

Earthworm-derived pore-forming toxin lysenin and screening of its inhibitors.

Lysenin is a pore-forming toxin from the coelomic fluid of earthworm Eisenia foetida. This protein specifically binds to sphingomyelin and induces erythrocyte lysis. Lysenin consists of 297 amino acids with a molecular weight of 41 kDa. We screened for cellular signal transduction inhibitors of low molecular weight from microorganisms and plants. The purpose of the screening was to study the mechanism of diseases using the obtained inhibitors and to develop new chemotherapeutic agents acting in the new mechanism. Therefore, our aim was to screen for inhibitors of Lysenin-induced hemolysis from plant extracts and microbial culture filtrates. As a result, we isolated all-E-lutein from an extract of Dalbergia latifolia leaves. All-E-lutein is likely to inhibit the process of Lysenin-membrane binding and/or oligomer formation rather than pore formation. Additionally, we isolated tyrosylproline anhydride from the culture filtrate of Streptomyces as an inhibitor of Lysenin-induced hemolysis.

General method for purification of α-amino acid-n-carboxyanhydrides using flash chromatography.

We describe the application of flash column chromatography on silica gel as a rapid and general method to obtain pure α-amino acid-N-carboxyanhydride (NCA) monomers, the widely used precursors for the synthesis of polypeptides, without the need for recrystallization. This technique was effective at removing all common impurities from NCAs and was found to work for a variety of NCAs, including those synthesized using different routes, as well as those bearing either hydrophilic or hydrophobic side chains. All chromatographed NCAs required no further purification and could be used directly to form high molecular weight polypeptides. This procedure is especially useful for the preparation of highly functional and low melting NCAs that are difficult to crystallize and, consequently, to polymerize. This method solves many long-standing problems in NCA purification and provides rapid access to NCAs that were previously inaccessible in satisfactory quality for controlled polymerization. This method is also practical in that it requires less time than recrystallization and often gives NCAs in improved yields.

Analysis and purification of alcohol-sensitive chiral compounds using 2,2,2-trifluoroethanol as a modifier in supercritical fluid chromatography.

2,2,2-Trifluoroethanol (TFE) is evaluated as an alternative modifier for the analysis and purification of alcohol-sensitive chiral compounds using supercritical fluid chromatography (SFC). Four chiral compounds, selected for their sensitivity to alcohols, in addition to a variety of standard chiral compounds were analyzed by SFC using TFE with polysaccharide and Pirkle-type chiral stationary phases (CSPs) to produce selectivities (alpha) and resolutions (Rs) as high as 1.4 and 7.2. A preparative isolation of 2-phenylglutaric anhydride was achieved using TFE as the mobile phase modifier to produce clean enantiomers.

A new nonadride derivative, dihydroepiheveadride, as characteristic antifungal agent against filamentous fungi, isolated from unidentified fungus IFM 52672.

In the screening of searching for new antifungal agents, a new nonaride compound, dihydroepiheveadride (1), was isolated from unidentified fungus IFM 52672 as the most potent antifungal principle from this organism. The structure of 1 was established on the basis of spectroscopic and chemical investigation, as well as detailed comparison of the spectroscopic and physico-chemical data of the oxidized derivative (3) from 1 with those of heveadride (2). Compound 1 showed strong antifungal activity against various filamentous fungi including human pathogens Aspergillus fumigatus, Penicillium marneffei and Trichophyton spp. It also showed the growth inhibition activity against certain human pathogenic yeasts such as Trichosporon species, while it had weak or no antifungal activity against Candida spp. and Cryptococcus neoformans, and no antibacterial activity against Bacillus subtilis nor against Escherichia coli. The antifungal potencies of compounds 2 and 3 were found to be weaker than that of 1.

A spectrophotometric method for the quantitative determination of purity of diethylenetriaminepentaacetic anhydride.

A spectrophotometric method has been developed for the quantitation of purity of diethylenetriaminepentaacetic anhydride (DTPA-A). This spectrophotometric method is conducted by measuring the absorbance at 275 nm of a 1.5 mg/ml solution of DTPA-A in dry dimethylformamide (DMF). The extinction coefficient at 275 nm for DTPA-A in DMF has been determined to be 0.437 ml/cm mg. Quantitation is accomplished by calculation using Beer's law. The assay response is linear for DTPA-A concentrations ranging from 0.05 to 2.0 mg/ml DTPA-A. The assay is specific, precise, and sensitive with a detection limit of 0.015 mg/ml DTPA-A and a quantitation limit of 0.06 mg/ml DTPA-A. The mean recovery from the sample filters employed for sample preparation in this assay is 97.8% (n = 6).

Isolation of salicylsalicylic acid, acetylsalicylsalicylic acid, and acetylsalicylic anhydride from aspirin tablets by extraction and high-pressure liquid chromatography.

Aspirin and four salicylate impurities of aspirin (salicylic acid, acetylsalicylsalicylic acid, acetylsalicylic anhydride, and salicylsalicylic acid) were resolved by silica gell TLC and by high-pressure liquid chromatography (HPLC) on a reversed-phase C18 column. Care was necessary in the choice of a column because of similar column failed to resolve these five compounds. Salicylsalicylic acid was isolated from aspirin tablets by extraction followed by reversed-phase C18 HPLC. The structure of this compound was confirmed by comparison with an authentic sample of salicylsalicylic acid by HPLC, TLC, IR and UV spectrophotometry, and mass spectrometry. Two other compounds, acetylsalicylic anhydride and acetylsalicylsalicylic acid, which had been previously identified by chromatography as impurities in aspirin, were isolated and further characterized.

[Formation of a depside-caffeine complex during cold conservation of coffee leaf samples in a hydro-ethanolic medium. Methodologic implications for the extraction of depsides]. / Sur la formation d'un complexe "depside-caféine" lors de la conservation, au froid, en milieu hydro-éthanolique, d'échantillons foliares de caféiers. Implications méthodologiques pour l'extraction des depsides.

The depsides present in coffee leaves are not apparent upon extraction with ethanol if the plant material has been fixed in boiling ethanol then maintained at - 25 degrees C. A complex formed with cafein prevents the extraction and this artefact from cold conservation concerns chlorogenic acid and its isomers. A treatment with chloroform can break the complex and allows the depsides to be dosed. The complex does not seem to exist in living tissues.