A DEFINIR
Oxidative stress, fungal chitosan, zebrafish.
Oxidative stress is a cause of numerous diseases in humans, this causes a constant search for new molecules that may have antioxidant capacity and prevent the emergence of diseases. The objective of this work was to extract chitosan from fungi (Chit-F) and synthesize a new molecule, conjugating it with gallic acid, which was called Chit-FGal, in order to potentiate its antioxidant action. After collection, isolation and identification of the fungus as being of the species Rhizopus arrhizus, it was possible to extract chitosan and after physical-chemical tests such as high performance liquid chromatography (HPLC), Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) ), it was confirmed that the sample was chitosan, with a degree of deacetylation of 86% and low molecular weight, in addition, without the presence of proteins and phenolic compounds. After that, the synthesis of fungal chitosan + AG (Chit-FGal) was successfully performed, confirmed by the 4x increase in the amount of phenolic compounds in relation to Chit-F, as well as the appearance of a peak in the region of the aromatic rings in the NMR analysis. When the 2 samples were extracted/synthesized and characterized, the in vitro antioxidant tests were performed (Copper Chelation, Iron Chelation, Total Antioxidant Capacity (CAT), reducing power and superoxide radical scavenging), where the samples had activities in all the tests, however Chit-FGal obtained results at least 50% (p <0.05) higher, demonstrating the potentiation of activities when modifying the native molecule. When testing Chit-F and Chit-FGal in fibroblast cells (3T3), there was no decrease in cell viability measured by MTT ((3-(4,5-Dimethylthiazolyl 2)-2,5-diphenyltetrazolium bromide) in any sample. , in addition, a protection test against damage caused by hydrogen peroxide was performed, where Chit-FGal at a concentration of 0.05 mg/mL showed better protection. A protective effect of embryos against damage caused by 0.06 mM hydrogen peroxide (100% live embryos) and 0.5% alcohol (93% live embryos) was obtained. acridine orange, where both Chit-F and Chit-FGal demonstrated protective action against cell death caused by hydrogen peroxide and alcohol. These results demonstrate the good antioxidant potential of chitosan extracted from soil fungi of the Caatinga biome (Chit-F), as well as the enhancement of this action by conjugating this polymer with gallic acid (Chit-FGal), which makes this new synthesized molecule promising for use as antioxidants with the potential to avoid a series of problems caused by oxidative stress.