Tenuipyrone, a novel skeletal polyketide from the entomopathogenic fungus, Isaria tenuipes, cultivated in the presence of epigenetic modifiers

The concomitant addition of the histone deacetylase inhibitor and the DNA methyltransferase inhibitor to the culture medium of an entomopathogenic fungus, Isaria tenuipes, greatly enhanced its secondary metabolite production and led to the isolation of tenuipyrone (1), a novel polyketide with an unprecedented tetracyclic ring system bearing a spiroketal structural component, along with two known C(10)-polyketides, cephalosporolide B (2), which is a plausible biosynthetic precursor of 1, and cephalosporolide F (3).     

Dihydrobenzofurans as cannabinoid receptor ligands from Cordyceps annullata,an entomopathogenic fungus cultivated in the presence of an HDAC inhibitor

The secondary metabolite production of Cordyceps annullata, an entomopathogenic fungus, was clearly enhanced by the addition of suberoyl bis-hydroxamic acid (SBHA), a histone deacetylase (HDAC) inhibitor, to the culture medium. Four new 2,3-dihydrobenzofurans, annullatins A–D (1–4), and a new aromatic polyketide, annullatin E (5) were isolated from the culture medium, and the structures, including the absolute stereochemistries, were determined by spectroscopic analysis, vibrational circular dichroism (VCD), and chemical transformations. Annullatin A (1) exhibited potent agonistic activity toward the cannabinoid receptors CB1 and CB2. Annullatin B (2) and D (4) displayed CB1 agonistic activity and CB2 inverse agonistic activity.     

Histone deacetylase inhibitor induced the production of three novel prenylated tryptophan analogs in the entomopathogenic fungus, Torrubiella luteorostrata

Suberoyl bis-hydroxamic acid (SBHA), a histone deacetylase (HDAC) inhibitor, led to significant changes in the secondary metabolism of an entomopathogenic fungus, Torrubiella luteorostrata, and induced the production of three new prenylated tryptophan analogs, luteorides A-C (1-3). The structures are characterized by the presence of an (E)-oxime group, which is an unusual functional group in natural products, and a 3-methylbuta-1,3-dienyl unit as a common substituent. The method of culturing entomopathogenic fungi in the presence of HDAC inhibitors, such as SBHA, is convenient and attractive for obtaining novel secondary metabolites.     

Novel spirocyclic trichothecanes, spirotenuipesine A and B, isolated from entomopathogenic fungus, Paecilomyces tenuipes

Entomopathogenic fungi forming fruiting bodies have been employed as tonics and antitussives from ancient times. Paecilomyces tenuipes, which is also called Isaria japonica, is a very popular entomopathogenic fungus and is often considered a health food in northeast Asian countries such as China, Korea, and Japan. We cultivated the fruiting bodies of Paecilomyces tenuipes. Among the large-scale cultivations, fruiting body grown in barley grain contained two novel spirocyclic trichothecane derivatives, spirotenuipesine A (1) and B (2), and known trichothecane mycotoxins. Compounds 1 and 2 showed potent activity in neurotrophic factor biosynthesis in glial cells. The isolation of these compounds indicated that P. tenuipes is a promising source for producing various biologically active substances including trichothecanes. It is noteworthy that trichothecane mycotoxins are present in Paecilomyces tenuipes, which is typically used in medicinal health food.     

Novel trichothecanes, paecilomycine A, B, and C, isolated from entomopathogenic fungus, Paecilomyces tenuipes

Paecilomycine A (1), B (2), and C (3) were isolated from cultivated fruiting bodies of Paecilomyces tenuipes (Isaria japonica), which is a popular entomopathogenic fungus used in folk medicine and health foods in China, Korea, and Japan. The structures of 1-3 were deduced from their spectroscopic data and their absolute configurations were elucidated by preparing their MPA esters. Compound 1 showed activity in the neurotrophic factor biosynthesis in glial cells.     

Formosadimers A, B, and C from the Bark of Calocedrus macrolepis var. formosana

Formosadimers A, B, and C, together with one known compound, sugikurojin B, have been isolated from the bark of Calocedrus macrolepis var. formosana. Formosadimers A, B, and C, and sugikurojin B are dimers of the abietane-O-abietane type. Their structures were elucidated principally based on spectroscopic data.     

Composition, antioxidant and antimicrobial activities of the seed essential oil of Calocedrus formosana from Taiwan

The hydrodistillated seed essential oil of Calocedrus formosana was analyzed to determine its composition and yield. Twenty-seven compounds were identified, the main ones being alpha-pinene (63.8%), totarol (9.9%) and ferruginol (8.9%). Monoterpene hydrocarbons (73.5%) and oxygenated diterpenes (18.8%) were the predominant groups of compounds. The seed essential oil exhibited excellent antioxidant, antimicrobial and anti-wood-decay fungal activities.     

Highly selective,kinetically controlled enolate formation using lithium dialkylamides in the presence of trimethylchlorosilane

The deprotonation of ketones and esters with lithium dialkylamides in the presence of trimethylchlorosilane leads to enhanced selectivity for the kinetically generated enolate. Lithium $\text{t}$-octyl-$\text{t}$-butylamide is shown to be superior to lithium diisopropylamide in the regio-selective generation of enolates and in the stereoselective formation of $\text{E}$ enolates.     

Agariblazeispirols A and B, an unprecedented skeleton from the cultured mycelia of the fungus, Agaricus blazei

Agariblazeispirols A and B, which have a unique steroidal skeleton, have been isolated from the cultured mycelia of Agaricus blazei (Agaricaceae). The absolute structure of Agariblazeispirol A was established to be (20S,22R,23R,24S)-13β,22:22,25-diepoxy-5-methoxy-14β-methyl-18-nor-des-A-ergosta-5,7,9,11-tetraen-23-ol by extensive 1D and 2D NMR spectral data, and X-ray analysis. The structure of Agariblazeispirol B was elucidated to be a stereoisomer of agariblazeispirol A at its carbon 22, (20S,22S,23R,24S)-13β,22:22,25-diepoxy-5-methoxy-14β-methyl-18-nor-des-A-ergosta-5,7,9,11-tetraen-23-ol by comparison of extensive 1D and 2D NMR spectral data with those of agariblazeispirol A. Both compounds showed a moderate circumvention of drug resistance on mouse leukemia P388/VCR cells.     

Crystallization specifics of carbonate-hydroxylapatite in the presence of strontium-containing agents

The effect of strontium-containing compounds on the crystallization of strontium-substituted carbonate- hydroxylapatite from a human synovial fluid prototype was studied. Synthesis products were investigated by FT-IR spectroscopy, X-ray diffraction, and differential thermal analysis. The amount of strontium in samples was determined by atomic emission analysis. For the synthesized phases, crystallite sizes were calculated by the Selyakov–Sherer formula, and the unit cell parameters were determined. The kinetically stable brushite phase was shown to transform into the more thermodynamically stable phase of strontium-containing carbonate-hydroxylapatite with increasing exposure time of precipitates under the mother solution. Some schemes were proposed for phase transformations under heat treatment.     

Biosynthesis, total syntheses, and antitumor activity of tanshinones and their analogs as potential therapeutic agents

Tanshinones are a series of abietane diterpenes, isolated exclusively from Salvia miltiorrhiza and related species. More than 40 tanshinones and their analogs have been isolated since the 1930s. Their biosynthetic pathway correlates with the MEP/DOXP pathway, and many key enzymes, such as mCPS, are responsible for establishing their molecular scaffolds and stereospeci?city. Because of their unique structural characteristics and promising biological activities, total syntheses of various tanshinones have attracted the interest of many synthetic chemists, including R. H. Thomson, H. Kakisawa, R. L. Danheiser, Y. Inouye and J. K. Snyder. Tanshinones and their analogs exhibit interesting and broad antitumor activity in various cell and animal models. Most recently, the tanshinone analog neo-tanshinlactone has shown potent and selective activity against breast cancer. This review will discuss the biosynthesis, total syntheses, and antitumor activities of tanshinones,especially neo-tanshinlactone and its analogs.     

Features of the extraction of essential oils from plant raw material in the presence of surface-active agents

It has been established that the influence of surface-active agents (SAAs), on the extraction of essential oils (EOs) is connected with a fall in the surface tension of water, which facilitates the process of steeping, wetting, and swelling of plant raw material and also the solubilization of the EOs in micellar solutions of SAAs. A. Sultanov Uzbek Scientific Research Institute of Pharmaceutical Chemistry, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 648–652, September–October, 1998.     

Highly stereoselective construction of functionalized cyclopropanes from the reaction between acetylenic esters and C-H acids in the presence of triphenylarsine

A one-pot triphenylarsine-catalyzed synthesis of trans-cyclopropane derivatives is achieved by means of the reaction between acetylenic esters and C-H acids in the presence of triphenylarsine. This procedure is simple and proceeds under mild reaction conditions. Its success depends on the choice of solvent, temperature and C-H acid used.     

Deprotonation of pyrazole and its analogs by aqueous copper acetate in the presence of triethylamine

Deprotonation reactions of pyrazole and its analogs by aqueous copper acetate in benzene at room temperature in the presence of triethylamine were studied. Unlike 3,5-dimethylpyrazole, more acidic pyrazole, 5-methyl-3-trifluoromethylpyrazole, and 3,5-bis(trifluoromethyl)pyrazoles are deprotonated to give pyrazolate bridges. The structural features of the obtained compounds are discussed based on X-ray diffraction data.     

Pyrene fluorescence in the presence of nonquenching and dynamic quenching salting-out agents

A new, simple, and rapid method to determine Setschenow (i.e., salting-out) constants for luminescent organic compounds in aqueous solutions has been developed using steady-state and time-resolved fluorescence measurements. Application of the new method was demonstrated using pyrene in the presence of nonquenching (K⁺) and dynamically quenching (Cs⁺) akali metal chloride salt solutions at room temperature. For these two model systems, Setschenow constants for pyrene salting-out by KCl and CsCl were determined to be 0.211 and 0.355 M⁻¹, respectively. We expect that the methodology reported in this paper can be applied equally well to interactions between a variety of salting-out agents and fluorescent biological and/or environmental molecules in aqueous solutions.     

Spectrofluorimetric determination of irinotecan in the presence of oxidant agents and metal ions

In this work four spectrofluorimetric methods for the determination of irinotecan (CPT-11) in human urine and pharmaceuticals have been developed. Initially, the fluorescent characteristics of irinotecan (CPT-11) have been studied in both acidic and basic media. Later, the fluorescence emission generated by the oxidation of CPT-11 with several agents was studied. A quenching of fluorescence could be observed in the presence of Ce(IV) and I₂/I⁻. Also, the reaction between several divalent and trivalent metal ions with CPT-11 was studied, and one method in presence of Fe³⁺ was developed since it was the only metal ion that changes the fluorescence of the analyte. The proposed methods present limit of detection comprises between 0.46 and 2.57 ng mL⁻¹. The spectrofluorimetric methods were applied to human urine. No pre-treatment of the sample was necessary, only a dilution 1:20 with water was made. No interference of the matrix was observed in the conditions used. Recoveries were comprises between 100.0 and 104.3%. Also, pharmaceuticals preparations were analyzed with recoveries between 106.7 and 119.7%. The proposed spectrofluorimetric methods were validated by RP-HPLC, obtaining that the oxidation with iodine is the best method to analyze urine samples, while than, the fluorimetric method developed at acidic pH value is the best for the analysis of pharmaceuticals.     

A new dihydroisocoumarin from the strain Aspergillus sp. CMM, an endophytic fungus of Cephalotaxus mannii

From the branch tissue of Cephalotaxus mannii, the endophytic fungal strain CMM was isolated and determined to belong to the genus Aspergillus according to its internal transcribed spacer (ITS) sequence of rDNA (ITS1-5.8S-ITS2). From the extracts of the fermentation broth of CMM, a new compound, namely 5-O-α-D-glucopyranosyl-5-hydroxymellein (1), was isolated, together with a known compound 4-hydroxymellein (2). Their structures were elucidated on the basis of 1D and 2D NMR data. Published in Khimiya Prirodnykh Soedinenii, No. 5, pp. 461–462, September-October, 2008.     

Stability of lyophobic colloids in the presence of metal chelates and chelating agents

Summary Coagulation, electrophoresis and adsorption data of various metal chelates and chelating agents on silver halide sols, PVC latex, and montmorillonite clay have been shown. The effects are most pronounced with the silver halide sols which are believed to be due to the coordination of the chelates and chelating agents with the crystal lattice ions of the colloidal particles. The PVC latex stability in the presence of the same solute species depends strongly on the concentration of the stabilizing surface active agent (dodecyl sulfate ions).

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Zusammenfassung Koagulations-, Adsorptions- und elektrophoretische Messungen an Silberhalogeniden, Polyvinylchlorid und Montmorillonit-Solen in Anwesenheit von verschiedenen Metallchelaten und Chelatbildnern werden dargestellt. Die beobachteten Effekte sind am stärksten bei den Silberhalogeniden, was durch die Koordination der Chelatkomplexe und der Chelatmoleküle mit den Gitterionen der Kolloidteilchen erklärt wird. Die Stabilität von Polyvinylchlorid-Latex gegen die gleichen Komplexe hängt stark von der Konzentration der grenzflächenaktiven potentialbestimmenden Ionen (Dodecylsulfat-Ionen) ab.

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Part of the plenary lecture entitled Chemical Aspects of Colloid Stability delivered at the 25 th Kolloid-Tagung in Munich on October 13–15, 1971.

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Supported by the National Science Foundation Grant GP 12220.