Síntese, caracterização e avaliação biológica de compostos anfifílicos obtidos de fontes químicas renováveis

Abstract

This work was divided into three chapters, in which was discussed the synthesis and characterization of amphiphilic compounds derived from renewable chemical sources (oil Pequi, Buriti and Babassu oil, fatty acids and carbohydrates). The first section describes the synthesis and characterization of fatty ethanolamides obtained by aminolysis of vegetable oils or pure methylic fatty esters with monoethanolamine and diethanolamine. The biological properties of the oils, mixtures of amides and pure amides were compared . Buriti oil showed the highest antioxidant activity (7.70 mg/mL) due to the higher concentration of carotenoids (692.98 mg/g). Amides derived from the same oil also showed higher antioxidant activity than other synthesized ethanolamides. The antibacterial activity of the mixtures of amides and amides pure evaluated against Gram-positive and Gramnegative bacteria was not significant. The second section describes the synthesis and characterization of lipophilic Nacylated diamines and aldonamides derived from D-glicono-1,5- lactone D-ribono-1,4- lactone or ester galactaric. To obtain the aldonamides, lactones and galactaric ester were treated with N-acylated diamines refluxing methanol in time ranging from 24-48 hours. The synthesized compounds had their in vitro biological properties evaluated. Antibacterial test against Gram-positive bacteria, Gram-negative and Methicillin resistant Staphylococcus aureus were performed, and also antifungal test against four species of Candida. The anti-inflammatory activity was investigated by the ability of the compounds to inhibit nitric oxide production by activated macrophages, cell viability was assessed by the MTT method. The aldonamides generally showed no activity, but the N-acylated diamines showed significants activities in antibacterial and antifungal tests. The results were comparable or even superior to those used as positive controls (chloramphenicol and itraconazole). For some compounds, it was possible to establish a correlation between lipophilicity and antifungal activity. However, in the cell viability tests , these compounds proved to be toxic at MIC. The third section describes the synthesis and characterization of N-acylhydrazones derived from D-glicono-1,5-lactone , D-ribono-1,4-lactone and galactaric ester. To obtain the N-acylhydrazones, the hydrazide derivatives of carbohydrates have been treated with aromatic aldehydes, using methanol as solvent at room temperature. The reaction times ranged from 24-72 hours. The compounds were obtained as mixtures of diastereomers, where E was the major isomer for all derivatives. The synthesized compounds were also examined for their in vitro biological properties. Antibacterial test against Gram-positive bacteria, Gram- negative, M. tuberculosis and antifungal test against four species of Candida were made, however the compounds were not active. The anti-inflammatory activity and cytotoxicity of these compounds are being evaluated in ICB-UFJF. Also in this last chapter, an attempt to cyclization of the N-acylhydrazones was performed to provide their respective, 1,3,4-oxadiazoles. However the desired compounds could not be obtained by the methodologies used.