Antiedematogenic activity of two thiazolidine derivatives: N-tryptophyl-5-(3,5-di-tert-butyl-4-hydroxybenzylidene) rhodanine (GS26) and N-tryptophyl-5-(3,5-di-tert-butyl-4-hydroxybenzylidene)-2,4-thiazolidinedione (GS28)

The search for new anti-inflammatory drugs has been constant in several research centers. The use of the Bioisostery concept allows the elaboration of new bioactive compounds with different properties through the introduction of substitute groups in one or more positions of a main molecule with known biological activity. Preliminary works accomplished at our laboratory with 2,4-thiazolidinedione isosters demonstrated inhibitory activity on edema formation for N-tryptophyl-5-(3,5-di-tert-butyl-4-hydroxybenzylidene)-2,4-thiazolidinedione (GS28) and N-tryptophyl-5-(3,5-di-tert-butyl-4-hydroxybenzylidene) rhodanine (GS26). We verified the antiedematogenic and ulcerogenic activity of these two compounds in Wistar rats. The carrageenan induced paw edema suffered significant (p<0.05) inhibition (28.36% on average) for GS28 (100 mg/kg; v.o.) during the entire time of the experiment. GS26 (50 and 100 mg/kg; v.o.) significantly inhibited (p<0.05) the paw edema dextran induced (22.1 and 27.8%, for the respective doses) after 180 min. The compounds GS26 and GS28 did not show ulcerogenic activity on gastric mucous. The results suggest antiedematogenic action for both compounds without the appearance of gastric lesions.     

Janoxepin and brevicompanine B: antiplasmodial metabolites from the fungus Aspergillus janus

Two compounds janoxepin (1) and brevicompanine B (2) were isolated from the fungus Aspergillus janus and the structures elucidated by one- and two-dimensional NMR spectroscopic methods and mass spectrometry. Janoxepin is a novel oxepin derivative with a rare d-leucine incorporated. Brevicompanine B has previously only been isolated from Penicillium brevicompactum. Both compounds were tested in antimicrobial assays and found to be active against the malaria parasite Plasmodium falciparum 3D7 (IC₅₀-values of 28 and 35 mg/ml, respectively). However, no activity was observed in antifungal or antibacterial assays.     

测定核黄素的化学发光新方法

研究了核黄素的化学发光性质，建立了一种测定核黄素的化学发光新方法，并应用于实际样品中核黄素的测定，与文献相比，本方法无需避光，而且分析体系和样品处理简单；干扰小，牛血清白蛋白、抗坏血酸、天冬氨酸等８种生物有机物质和 Ｃｕ（Ⅱ）、Ｚｎ（Ⅱ）、Ｆｅ（Ⅲ）等１５种常见金属离子的允许量较大；核黄素溶液浓度在０． １０～５０ ｍｇ／Ｌ范围内，与化学发光强度成正比，方法线性范围宽；测定１．０ｍｇ／Ｌ核黄素溶液１２次，求得相对标准偏差为２．９％，方法精密度高；方法的检测限为０．０７５ ｍｇ／Ｌ，灵敏度高。     

Thermal degradation of some polymers based on ethylene glycol dimethacrylate

Thermogravimetric analysis and pyrolysis in combination with gas chromatography were used to study the thermal behaviour of some cross-linked polymers of ethylene glycol dimethacrylate. The investigated polymers show a complex thermal degradation mechanism. The complexity of the reaction increases together with increase of the ethylene glycol chain in the macromolecule and with increase of the pyrolysis temperature. At low temperature, the thermal decomposition products of the analyzed polymers are mainly the constituent monomers. At high temperatures, besides the monomer, other decomposition products are formed as a result of thermal cracking reactions, i.e. secondary reactions of decomposition and recombination.

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Zusammenfassung Zur Untersuchung des thermischen Verhaltens einiger quervernetzter Polymere auf Äthylenglykoldimetacrylatbasis wurden thermogravimetrische Analyse und Pyrolyse in Zusammenhang mit der Gaschromatographie angewendet. Die untersuchten Polymere zeigten einen komplexen thermischen Zersetzungsmechanismus. Die Komplexizität der Reaktion nimmt mit Zunahme der Anzahl der Äthylenglykolketten im Makromolekül und mit Zunahme der Pyrolysentemperatur gleichermaßen zu. Bei niedrigeren Temperaturen stellen die Hauptzerfallsprodukte der analysierten Polymere hauptsächlich deren Monomere dar. Bei höheren Temperaturen werden als Ergebnis thermischer Krackreaktionen, z. B. sekundäre Zersetzungs- und Rekombinationsreaktionen, neben den Monomeren auch andere Zersetzungsprodukte gebildet.

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Comparative study of the phenolic profile,antioxidant and antimicrobial activities of leaf extracts of five Juniperus L. (Cupressaceae) taxa growing in Turkey

Abstract

The purpose of this study was to conduct a comparative evaluation of some biological properties of methanol and water extracts of leaves of five Juniperus taxa growing in Turkey: J. communis L. var. communis (Jcc), J. communis L. var. saxatilis Pall. (Jcs), J. drupacea Labill. (Jd), J. oxycedrus L. subsp. oxycedrus (Joo), J. oxycedrus L. subsp. macrocarpa (Sibth. & Sm.) Ball. (Jom). The antioxidant properties were examined in vitro; both in the DPPH and in the reducing power tests, Joo methanol extract resulted the most active (IC₅₀?=?0.09?±?0.01mg/mL and ASE/mL?=?2.56?±?0.06). In the TBA assay, Jcs methanol extract exhibited the highest activity (IC₅₀?=?4.39?±?0.47?μg/mL). The extracts displayed bacteriostatic activity against Staphylococcus aureus, and Jd methanol extract resulted the most effective (MIC?=?19.53?μg/mL); no effect on the S. aureus biofilm formation was observed. The extracts resulted non-toxic in the Artemia salina lethality bioassay. Finally, the phenolic profile of the methanol extracts was characterized by HPLC-PDA/ESI-MS.     

Single molecule spectroscopy as a probe for dye-polymer interactions

Experimental (Single Molecule Spectroscopy) and theoretical (quantum-chemical calculations and Monte Carlo and molecular dynamics simulations) techniques are combined to investigate the behavior and dynamics of a polymer-dye molecule system. It is shown that the dye molecule of interest (1,1'-dioctadecyl-3,3,3',3'-tetramethylindo-dicarbocyanine) adopts two classes of conformations, namely planar and nonplanar ones, when embedded in a poly(styrene) matrix. From an in-depth analysis of the fluorescence lifetime trajectories, the planar conformers can be further classified according to the way their alkyl side chains interact with the surrounding poly(styrene) chains.     

Direct HPLC resolution of beta-aminoalcohol (tazifylline,ranolazine, sotalol) enantiomers

Summary A routine chiral analysis has been developed to control the optical purity of chiral drugs and to monitor their asymmetric synthesis. The recent advent of new chiral stationary phases for HPLC enabled us to achieve the direct resolution of chiral drugs without any derivatization. The factors affecting chiral resolution on a new alpha₁-acid glycoprotein column (EnantioPac, LKB) were assessed with three beta-aminoalcohols.