A Simple Way for the Preparation of Natural Antioxidant Quercetin from Rutin by Subcritical Water.

Context: Quercetin (QR) is a natural strong antioxidant of the plant origins. It is used for treating conditions of heart and blood vessels including "hardening of arteries" (atherosclerosis), high cholesterol, heart disease, circulation problems, preventing cancer, for treating chronic infections of the prostate, etc.

Aims: The aim of this work was to development and study of an acid-free technique for the preparation of QR from rutin (RT) that requires no use of acids and toxic organic solvents.

Study of an Acid-Free Technique for the Preparation of Glycyrrhetinic Acid from Ammonium Glycyrrhizinate in Subcritical Water.

The aim of this work was to study an application of a previously developed expedient acid-free technique for the preparation of glycyrrhetinic acid from ammonium glycyrrhizinate that requires no use of acids and toxic organic solvents. Subcritical water that serves as a reactant and a solvent was used in order to obtain glycyrrhetinic acid in good yields starting from ammonium glycyrrhizinate. It has been shown that variation of only one parameter of the process (temperature) allows alteration to thecomposition of the hydrolysis products.

Study of molecular complexation of glycyrrhizic acid with chloramphenicol by electrospray ionization mass spectrometry.

Context: Glycyrrhizic acid (GA) is a triterpene glycoside representing the main active component of licorice root extract obtained from plants of the Glycyrrhiza glabra L. and widely used as a complex-forming agent for the synthesis of new transport forms of the well-known drugs.

Aims: For the first time, the complexation of GA with chloramphenicol antibiotic (ChlA) was investigated by electrospray ionization mass spectrometry (ESI MS).

Effect of quinone on the fluorescence decay dynamics of endogenous flavin bound to bacterial luciferase.

The interaction of quinone with luciferase from Photobacterium leiognathi was studied based on the fluorescence decay measurements of the endogenous flavin bound to the enzyme. Homologous 1,4-quinones, 1,4-benzoquinone, methyl-1,4-benzoquinone, 2-methyl-5-isopropyl-1,4-benzoquine and 1,4-naphthoquinone, were investigated. In the absence of quinone, the fluorescence intensity and anisotropy decays of the endogenous flavin exhibited two intensity decay lifetimes (~1 and 5 ns) and two anisotropy decay lifetimes (~0.