Susan Ensel (Hood College, USA)
“Contains antioxidants!” is a common marketing slogan, but what really constitutes a good antioxidant? We have designed an organic chemistry laboratory experiment to investigate relative antioxidant potential and the concomitant structural changes that occur in oxidation reactions. Our interest focused on p-coumaric acid, ferulic acid, and caffeic acid which are naturally occurring phenylpropenoic acids differing only in substituent abundance and location on the aromatic ring. Using oxygen sensors, we measured the rate at which molecular oxygen was consumed in a typical sulfite oxidation reaction with individual antioxidants present. Relative antioxidant potential was also measured using the DDPH radical scavenging assay. In addition, we analyzed the products of a periodate oxidation reaction via LC-MS in an effort to better understand structural changes that occur due to the oxidative process. The information gathered through this experiment will help organic chemistry students understand which structural moieties improve a compound’s antioxidant potential.