Determination of antioxidant activity of phenolic antioxidants in a Fenton-type reaction system by chemiluminescence assay.

The hydroxyl radical (*OH) has been implicated in various diseases, and it is therefore important to establish efficient methods to screen hydroxyl radical scavengers for antioxidant therapy. In this paper, a simple chemiluminescence assay was established to evaluate the *OH-scavenging capacity of phenolic compounds. This assay took advantage of the transient property of the Fenton reaction and the reaction between luminol and the hydroxyl radical, and effectively avoided the pro-oxidant action of some phenolic compounds. Fifteen phenolic compounds were assessed for their antioxidant activity in the Fenton reaction system, and even in the case of "pro-oxidants" that were excluded from the widely used deoxyribose (DR) assay. Since it overcomes the challenges that the traditional DR assay encounters, our method has promising applicative values: it is low-cost, time-saving, and reliable. It would also be more favorable than electron spin resonance (ESR) and radiolysis technology, which are known to be expensive and not commonly available to those specialized in free radical biology and medicine.