Presumptive Relationship between Oxidoreduction Potential and Both Antibacterial and Antioxidant Activities of Herbs and Spices: Oxidoreduction Potential as a Companion Tool for Measuring the Antioxidant Activity

Abstract

Antibacterial and antioxidant activities form an essential component of the bioactive properties of plant products. The antibacterial and the antioxidant properties of three types of aqueous extracts of four herbs and spices were evaluated. While the total phenolic content, DPPH radical scavenging activity and oxidoreduction potential methods were used for the antioxidant properties determination, the inhibition diameters of extracts toward the growth of Staphylococcus warneri, Bacillus cereus, Enterobacter cloacae and Proteus vulgaris were evaluated. Although the phenolic content did not correlate with the antibacterial activity of plant extracts, it linearly correlated (R2 = 0.827) with DPPH scavenging activity of the studied plants following the order: sumac > ginger > rosemary > cinnamon. The oxidoreduction potential values linearly correlated with both the phenolic content (R2 ≈ 0.88) and DPPH scavenging activity values (R2 ≈ 0.96). The oxidoreduction potential could be proposed as a useful companion tool combined with other techniques when determining the antioxidant activity of plant extracts and food products is considered.