Investigation of the Antioxidant and Antibacterial Activity of Novel Quercetin Derivatives

Our previous work involved the preparation and characterization of six quercetin derivatives, three of which were novel Schiff bases, while the fourth was a novel ionic salt of iodine. This study involved the investigation of the in vitro antioxidant activity against DPPH free radical as well as the in vitro antibacterial activity against Bacillus cereus, Salmonella spp., Escherichia coli and Staphylococcus aureus of quercetin and its 1-6 derivatives. The results revealed that all the studied quercetin derivatives had shown less antioxidant and antibacterial activity than quercetin itself, except that of compounds 3 and 4, which displayed an improvement in the antibacterial activity against Escherichia coli as compared to that of quercetin.