Antioxidant activity of polyphenols from larch wood: an amperometric study

Abstract

Purpose The purpose of this paper is to determine the antioxidant activity of natural polyphenols from larch wood by the amperometric method. Design/methodology/approach Direct measurements of antioxidant activity were carried out by the amperometric method in an oxidizing mode with glassy carbon as a working electrode, set potential +1.3V and using a flow-injection system with 2.2 mM phosphoric acid as the mobile phase with a flow rate of 1.2 ml/min. Findings The reported results show the following values of antioxidant activity for the tested compounds: (−)-secoisolariciresinol – 0.199 ± 0.002 mg/L (p < 0.05); isolariciresinol – 0.196 ± 0.002 mg/L (p < 0.05); lariciresinol - 0.222 ± 0.001 mg/L (p < 0.05); O-isopropylidene derivative of (−)-secoisolariciresinol - 0.143 ± 0.002 mg/L (p < 0.05); (+)-dihydroquercetin – 0.153 ± 0.002 mg/L (p < 0.05); and quercetin – 0.521 ± 0.001 mg/L (p < 0.05). The last product was tested as the reference of a widely used current antioxidant. General tendencies of determined values of antioxidant activity for studied compounds are in good correlation with published data as determined by the t-BuOOH-initiated lipid peroxidation method. Practical implications Described results show practical applicability of the amperometric method as being faster and cheaper in comparison to other methods, including oxygen radical absorbance capacity (ORAC) assay or 2,2′diphenyl-1-picrylhydrazyl (DPPH) reagent based assay. Originality/value The described results show the first-time application of the amperometric method for the evaluation of the antioxidant activity of phenolic compounds from larch wood.