A solid-phase synthetic approach to pH-independent rhodamine-type fluorophores.

An efficient methodology using the Fukuyama-Mitsunobu reaction was successfully applied to prepare various Rhodamine B-based amides with the locked possibility to form a lactam ring. The procedure was developed for solid-phase synthesis, which can be advantageously applied to the synthesis of chemical libraries in a combinatorial fashion. A series of derivatives including aliphatic as well as aromatic rhodamine amides alkylated via a reaction with various alcohols were synthesized, and their spectral properties were investigated. Blocking lactamization via N-alkylation enabled us to prepare rhodamine derivatives with an excellent fluorescence response. In comparison to their non-alkylated counterparts, these derivatives exhibited pH independence and higher quantum yields.

Study and application of noncatalyzed photoinduced conjugation of azides and cycloocta-1,2,3-selenadiazoles.

The non-catalyzed cycloaddition of eight structurally different azides with cyclooctyne generated in situ by the photolysis of cycloocta-1,2,3-selenadiazole gives 1,2,3-triazole derivatives as the main products. The application of this reaction was demonstrated by the photoconjugation reaction of cycloocta-1,2,3-selenadiazole with an avidin-modified biotin complex to introduce a new strategy in the non-catalyzed synthesis of bioconjugates.

DNA interstrand cross-linking agents and their chemotherapeutic potential.

DNA interstrand cross-linking (ICL) agents are an important group of cytotoxic drugs with the capability of binding covalently between two strands of DNA, thereby preventing vital processes such as replication or transcription in dividing cells. In anticancer therapy however, their potential is limited due to the resistance by various mechanisms. In order to develop highly effective antitumor drugs it is necessary to study both effective ICL formations and their subsequent repair mechanisms. This review presents an overview of development over the past decade and the use of both well-known and new DNA interstrand cross-linking agents. Their potential in applications especially as anticancer chemotherapeutics in the framework of current knowledge of repair mechanisms and development of combined chemotherapy is discussed.

3-Hydroxy-2-phenyl-4(1H)-quinolinones as promising biologically active compounds.

2-Phenyl-3-hydroxy-4(1H)-quinolinones can be considered as aza-analogues of flavones, compounds which are known for the wide-range of their biological activity. These quinolinones were studied as inhibitors of topoisomerase, gyrase and IMPDH. They were tested for anticancer activity in-vitro and were also shown to possess immunosuppressive properties. This review is the first summarizing the synthesis and activity of the mentioned quinolinones.

Simple method for determination of dietary fiber in frozen foods.

A simple method was developed for the determination of dietary fiber in multicomponent foods. The method involves dispersing the sample into pH 7.4 phosphate buffer and adding bile and pancreatic enzyme as described. Results were comparable to AOAC methods with correlation coefficients of 86% for multicomponent dinners and 89% for breakfast foods. Coefficients of variation ranged from 7.4 to 20.0% for multicomponent foods and 1.0 to 3.6% for single component foods. In addition, blind duplicate samples had a correlation of 0.99. The described method required less time, labor, and manipulation than AOAC methods.

Rapid determination of cholesterol in single and multicomponent prepared foods.

A rapid method has been developed for cholesterol determination in single and multicomponent foods. The method involves alcoholic KOH saponification of the samples, extraction of the nonsaponifiable fraction with hexane, and injection of concentrated extract into the gas chromatograph without derivatizations. It has been applied to a wide variety of frozen and refrigerated foods. More than 300 samples were analyzed with a coefficient of variation (CV) ranging from 0.5 to 8.6%. The average recoveries of cholesterol from spiked oil and tomato vegetable soup samples were 100 +/- 1.5% and 99.7 +/- 1.6% and the CVs were 1.5 and 1.6%, respectively. This method reduces labor by > 70%, eliminates dangerous chemicals, and minimizes solvent use, compared to the AOAC method and other methods cited in the manuscript. The method was used successfully on a wide variety of multicomponent foods. We recommend this method for collaborative study under the AOAC guidelines for method approval.