Synthesis, Characterization and Antioxidant and Antimicrobial Activities of Sulfonated Quercitin-Metal Complexes

OBJECTIVE To research the synthesis and antioxidant and antimicrobial activity of metal complexes of sulfonated quercitin. METHODS Four sulfonated quercitin-metal complexes were prepared through the reaction of sulfonate and metal coordination, the antioxidant and antimicrobial activity of metal complexes were detected by clearance rate of DPPH and bacteriostatic annulus size. RESULTS The inhibitory effect of Staphylococcus aureus and Escherichia coli through the increase of concentration and improve of the sulfonated quercitin-zinc complexes. In the concentration of 7.5 mg·mL^-1, the bacteriostatic annulus of Staphylococcus aureus size was 3.60 mm and no inhibition of Escherichia coli by sulfonated quercitin-zinc complexes. The clearance of DPPH improved with concentration and improve of sulfonated quercitin-metal complexes increased. In the concentration of 40 mg·mL^-1, the clearance rate of DPPH were 47.55%, 91.40%, 46.74%, 68.22%, respectively by sulfonated quercitin-zinc complexes, sulfonated quercitin-copper complexes, sulfonated quercitin-cobalt complexes and sulfonated quercitin-manganese complexes. CONCLUSION The sulfonated quercitin-metal complexes through the reaction of sulfonate has antibacterial and antioxidant activity.