A espectroscopia de emissão e sua aplicação no estudo de moléculas orgânicas com interesse farmacológico

Abstract

The bioactive organic molecules (MOB) have their application extended both in physics and in medicine due to their photophysical properties. The study of the interaction of these molecules with the biological environment is a way to enhance these effects, especially pharmacological effects. This type of study often because they are indirect measures leave some unknowns regarding: active species; transport mechanism in the biological membrane; type of interaction and associative site. Emission spectroscopy using pseudomembranes (micelles) makes it possible to answer or elucidate these questions. We sought to analyze three MOBs: DHMC, Harmina and APNH. All with aromatic ring in their structures and distinct biological properties: antifungal, hallucinogenic and carcinogenic, respectively. DFT calculations based on 6-31 + G * and functional B3LYP were used with the Spartan16 ® and Origin ® program simulating hydrophilic and hydrophobic environments. Subsequently, spectroscopic measurements of UV-VIS absorption and emission (λexc = 313nm) were performed in hydrophobic, hydrophilic solvent and in micelles (neutral, anionic and cationic). The DHMC action species is DHMC-H. DHMC + deprotones and enters the micelle and remains anchored in its hydrophilic region. The Harmina molecule behaved differently according to the micelle charge. When the micelle is neutral, the deprotoned monocation and within the micelle two species coexist: HR anchored in the hydrophobic region and the HR-H species anchored in the hydrophilic region. Now when the micellar load is negative, Harmina has HR-forte as its active species. This species is anchored in the aqueous region, forming a hydrogen bonding complex between the nitrogen of the HR species pyridine. The micellar charge also provided a distinct photophysical behavior for the APNH molecule. The neutral micelle emission was similar to the photophysical behavior in hydrophilic medium. The APNH entered the micelle and stayed in the region close to the surface. APHH in anionic micelle had its photophysical properties canceled and in cationic micelle APNH was in the hydrophobic region (in the micelle nucleus). This photophysical behavior helps to clarify the understanding of the mechanism of transport of APNH into a micelle. It also helps to understand the carcinogenicity of this molecule in front of cells. The emission systems along with the other methodologies were effective in studying the photophysical properties of these molecules, demonstrating that this methodology is also a way of helping to understand the drug / pseudomembrane interaction, providing an idea of the pharmacological action.