SPECTROSCOPIC STUDY OF THE PROCESS OF HYPOCHROMIC EFFECT IN SOL T IN SOLUTIONS OF N UTIONS OF NATURAL D TURAL DYES AND VI YES AND VITAMIN B2 AMIN B2

The process of self-assembly of riboflavin molecules in aqueous and binary mixtures of solvents was investigated by the spectroscopic method. It was shown that during the assembly of vitamin B2 molecules, dipole-dipole interaction occurs, as a result of which resonant splitting of excited electronic levels of riboflavin molecules occurs. And the observable hypo chromic effect is due to a decrease in the intense absorption capacity of the aggregated riboflavin molecules themselves.

Helical-Ribbon and Tape Formation of Lipid Packaged [Ru(bpy)3]2+ Complexes in Organic Media

Anionic lipid amphiphiles with [RuII(bpy)3]2+ complex have been prepared. The metal complexes have been found to form ribbon and tape structures depending on chemical structures of lipid amphiphiles. Especially, the composites showed hypochromic effect and induced circular dichroism in organic media, and flexibly and weakly supramolecular control of morphological and optical properties have been demonstrated.

The Native Monomer of Bacillus Pumilus Ribonuclease Does Not Exist Extracellularly

Supported by crystallography studies, secreted ribonuclease of Bacillus pumilus (binase) has long been considered to be monomeric in form. Recent evidence obtained using native polyacrylamide gel electrophoresis and size-exclusion chromatography suggests that binase is in fact dimeric. To eliminate ambiguity and contradictions in the data we have measured conformational changes, hypochromic effect, and hydrodynamic radius of binase. The immutability of binase secondary structure upon transition from low to high protein concentration was registered, suggesting the binase dimerization immediately after translocation through the cell membrane and leading to detection of binase dimers only in the culture fluid regardless of ribonuclease concentration. Our results made it necessary to take a fresh look at the binase stability and cytotoxicity towards virus-infected or tumor cells.

Interaction of Duloxetine Hydrochloride with Deoxyribonucleic Acid Measured by Fluorescence Spectroscopy

Interactions with many clinically active therapeutic agents with DNA are well studied and it is necessary to decipher the structure of DNA and to investigate the pathological implications of those molecules in living organism. This study investigated the interaction of antidepressant drug Duloxetine-hydrochloride (DLX) with calf thymus DNA (ct-DNA). The interaction of DLX with ct-DNA was studied employing fluorescence spectroscopy. Hypochromic effect was found in the absorption spectra of duloxetine, and its wavelength had no shift in the presence of DNA indicating external binding mode of duloxetine to DNA. Fluorescence spectroscopic results showed the quenching of fluorescence intensity of DLX in presence of DNA indicating the interaction between DLX and DNA. Hydrophobic interaction and hydrogen bonding played the dominating role in DLX-DNA binding and binding forces also indicate the binding site of duloxetine to be at the minor groove of DNA.Dhaka Univ. J. Pharm. Sci. 14(2): 199-206, 2015 (December)