Dmitry D. Evtyugin, Dmitry V. Evtuguin
Samples with different contents of ellagic acid (EA) (55–94 %), isolated from sulphite spent liquor (SSL) of acid sulphite pulping of Eucalyptus wood, were examined for their antioxidant (AOX) activity towards the stable free 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and compared with several natural and synthetic antioxidants. Using a spectrophotometric approach with stoichiometric and kinetic parameters, AOX potentials were ordered as follows: EA > pyrogallol > caffeic acid ≈ Trolox > > butylated hydroxytoluene. Although the AOX activity in EA formulations was mainly attributed to EA, the contribution of concomitant lignin was not negligible. The importance of prior purification of EA formulations for enhanced AOX properties was highlighted. No significant synergistic or antagonistic effects of concomitants on the AOX activity of EA were detected. EA was suggested to be a prominent natural alternative to synthetic AOX for food applications and polymer matrices in food packaging, being a potentially safe solution for health and environment.