PFSPD at all concentrations produced the highest (pb0.05) inhibition percentage of ferrozine-Fe+2 complex formation,
with higher concentrations (25, 50 and 100 mg/mL). At lower concentrations (0.78–12.5 mg/mL) PFSPw showed higher (pb0.05) chelating activity than PFSPM. In PFA samples, as occurred with PFSP, the samples extracted with DMSO showed higher (pb0.05) chelating activity at all concentrations than the samples extracted with methanol. At highest concentration (100 mg/mL), no statistically significant differences (p>0.05) were found between the PFSPD and PFAD.