Study of the protective capacity of a β-cyclodextrin polymer with chlorogenic acid (coffee antioxidant)

Abstract

This study focuses on coffee as a source of antioxidants, hence, protecting from the damage caused by free radicals; which has been demonstrated to have a protective action in numerous diseases. This capacity is attributed to its phenolic compounds among which chlorogenic acid stands out, together with caffeic acid. Besides, cyclodextrins are well known for their capacity of forming inclusion complexes where the host molecule is located in the interior cavity, allowing the transport and storage of it. My experimental project is focused on the synthesis and characterization of a protective polymeric system formed by β-cyclodextrin, which is then going to be loaded with chlorogenic acid. This inclusion complex as well as the β-cyclodextrin polymer and chlorogenic acid themselves, have been studied through preliminary studies of stability, using principally UV and FTIR spectroscopies as well as thermogravimetric calorimetry, which showed that the polymer prevents the acid from degrading through time, when maintained either at dark or in direct sunlight. The protective effect has been determined through scavenging capacity measurements analyzing the variation in the activity of chlorogenic acid as well as its change when the acid is introduced into β-cyclodextrin. For this, it has first been studied the change in absorbance using a mixture of 2,2-diphenil- 1-picrylhydrazyl (DPPH) and chlorogenic acid at different concentrations; leading to the already known fact that, at higher concentrations, the antioxidant capacity increases. Furthermore, the controlled release of the antioxidant from the cavities of the β- cyclodextrin in the polymeric matrices has been studied through Sotax Dissolution tests and applying mathematical models. This data leads to the conclusion that the CD-chlorogenic acid inclusion complex helps to maintain the integrity and scavenging activity of the bioactive compound especially when the chlorogenic acid is measured over time.