Deciphering the Interaction of Steroidal Biosurfactants with Some Small Molecules and Macromolecules of Biological Relevance: A Photophysical Approach

Abstract

Bile salts, belonging to the class of natural steroids also known as steroidal biosurfactants, are one of the most important surfactants in living organisms contained in the bile of mammals. Due to the steroid rigidity and the peculiar distribution of hydrophobic and hydrophilic domains, these molecules self-organize in unique ordered supramolecular assemblies in solution. They facilitate the absorption of cholesterol, phospholipids, fatty acids, and fat soluble vitamins etc. from the intestine and help in their transfer to the surface of mucosal cell lining of the small intestine. Bile salts, with the advantage of physiological compatibility are frequently used in pharmaceutical formulations for enhancing drug solubility, maintaining drug stability, and improving the permeation, absorption, and bioavailability of drugs. In addition, importance of biosurfactants increases in the field of protein isolation and purification. The extensive use of bile salts in biochemical research necessitates a comprehensive study of their interaction with other biologically important molecules and macromolecules at a molecular level. Moreover, in order to use bile salts for drug delivery purposes, understanding its interaction with biological macromolecules especially some drug binding proteins becomes important. With this motivation the objective of the present thesis is to decipher the interaction between bile salts and some selective molecules and macromolecules of biological relevance using the intrinsic fluorescence properties of the chosen molecules.