Elucidação estrutural, polimorfismo e estudo físico-químico das riparinas

Abstract

Riparins I and II are alkamides that have been isolated and synthesized by Barbosa-Filho et al. (1990). from a typical Amazonian plant, scientifically called Aniba riparia. These molecules are formed from the junction of tyramine with benzoic acid, and their chemical structures differ by the substitution of a hydroxyl in the aromatic ring. Several researchers have begun studies on its potential therapeutic effects in preclinical studies, elucidating its therapeutic effects in animal behavioral models, including antidepressant, anxiolytic and antibacterial effects. This project had the main objective the physical-chemical characterization of riparins I and II, focusing on thermal analysis and identification of possible polymorphs. In order to obtain these results several techniques were used, such as: Raman and infrared spectroscopy, thermogravimetry (TG), differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD) and single-crystal X-ray diffraction (SCXRD). The crystalline structure of riparin II was elucidated, due there is no data reported in the literature. Riparins II a higher melting point compared to riparin I, which can be explained by the hydroxyl in the chemical structure of riparin II, that forms an intramolecular bonding O7A•••H2A— O2A, occasioning a major stability in this substance. Moreover, it was possible to detect the phenomenon of the polymorphism in riparina I, becoming its study essential in order to avoid less stable and less secure polymorphs, ensuring safety and efficacy in administering the product and optimizing preclinical studies.