DNA binding study of rhodamine B and its derivatives

International Conference and Exhibition on Molecular Medicine and Diagnostics

August 24-26, 2015 London, UK

Md Maidul Islam

Posters-Accepted Abstracts: J Mol Genet Med

Abstract :

Food additives are substances added to food to preserve flavor or enhance its taste and appearance. Food coloring, or color additive,
is any synthetic or natural dye, pigment or substance that imparts color when it is added to food or drink. Besides coloring
food, food-dyes also show a several bioactivities. A lot of natural and synthetic dyes show antioxidant, antimicrobial and anticancer
activity. We studied Rhodamine B (a common food dye in India) and its derivative with double stranded DNA structure using
various biophysical techniques. All the derivatives bound with DNA showing the binding affinities in the order 105-106 M-1. Circular
dichroic results suggested that the conformation of DNA was perturbed by all the derivatives. Fluorescence quenching studies gave
evidence for groove binding mode. Isothermal titration calorimetry revealed that the binding was characterized by negative enthalpy
and positive entropy changes. The overall binding affinity of the derivatives to the DNA revealed that other derivatives of Rhodamine
bind strongly in comparison to Rhodamine B. The temperature dependence of the enthalpy changes afforded large negative values
of heat capacity changes for the binding to ds DNA suggesting substantial hydrophobic contribution in the binding process. These
results further advance our understanding on the binding of food dyes to DNA sequences.