Novel Protein-Based Solid-Biosensor for Determining Pro-oxidant Activity of Phenolic Compounds

Area of Science:

• Biochemistry
• Analytical Chemistry
• Materials Science

Background:

• Phenolic compounds exhibit pro-oxidant activities, particularly under specific conditions.
• Accurate measurement of antioxidant pro-oxidant activity is crucial for various applications.
• Existing methods for assessing pro-oxidant activity can be complex or costly.

Purpose of the Study:

• To develop a novel, cost-effective protein-based biosensor for measuring the pro-oxidant activities of phenolic compounds.
• To utilize egg white proteins for creating a stable and reusable biosensor.
• To determine the Cu(II)-induced pro-oxidant activity of various antioxidants.

Main Methods:

• Egg white proteins were precipitated with calcium chloride to form an insoluble calcium proteinate complex biosensor.
• The biosensor detects Cu(I) ions, formed by the reduction of Cu(II) by antioxidants, which indicates pro-oxidant activity.
• Colorimetric determination of protein-bound Cu(I) was performed at 450 nm using neocuproine (Nc).

Main Results:

• The developed biosensor successfully determined the Cu(II)-induced pro-oxidant activity of phenolic compounds like gallic acid, catechin, and quercetin.
• The method was applied to analyze synthetic mixtures and herbal infusions (sage, green tea, mint, marjoram).
• Results from the biosensor assay showed good agreement when compared to a modified carbonyl detection assay.

Conclusions:

• A stable, low-cost, and reusable protein-based biosensor for assessing antioxidant pro-oxidant activity has been successfully developed.
• This biosensor offers a practical method for quantifying the pro-oxidant effects of phenolic compounds in complex matrices.
• The biosensor preparation is scalable and suitable for long-term use.