Interaction of Human Intestinal Bile Salt with Bioactive Diet Capsaicin and Indole-3-Carbinol

Human intestinal bile salts are well-known for their solubilization and emulsification action in cosmetics, medicines, and chemicals. Here, an effort has been made to understand the solubilization mechanism of bioactive diet capsaicin (Cap) and indole-3-carbinol (I3C) in sodium taurocholate (NaTC) bile salt aggregates using both intrinsic and extrinsic fluorescent probes. Fluorescence study concludes that the NaTC micelle solubilizes both Cap and I3C. An increase in nonpolarity of the NaTC micellar environment is responsible for the solubilization of both Cap and I3C which is further confirmed by using an extrinsic probe Nile red (NR). Both Cap and I3C bind to the NaTC micelle as confirmed from the binding constant value. The location of both the bioactive molecules in the NaTC micelle has been confirmed from fluorescence quenching study using potassium iodide as a quencher. The effect of both I3C and Cap on the size of the NaTC micelle has been analyzed using dynamic light scattering.