Comparative profiling of clove extract and its component antioxidant activities against five reactive oxygen species using multiple free radical scavenging

Clove (Syzygium aromaticum L.) is recognized to have strong antioxidant activity, as revealed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, β-carotene bleaching, and ferric reducing power assays. The present study was undertaken to determine the radical scavenging profiles of clove extract against five reactive oxygen species (ROS: Hydroxyl radical, superoxide, alkoxyl radical, peroxyl radical, and singlet oxygen) using the multiple free-radical scavenging (MULTIS) method. The clove extract was shown to be effective in scavenging singlet oxygen. Further, ROS scavenging measurements for three antioxidant components of cloves (eugenol, β-caryophyllene, and eugenol acetate) were carried out. The MULTIS measurements suggested that eugenol plays the major role in the overall scavenging activity of clove as a food. Based on the results, the singlet oxygen scavenging mechanism of eugenol is discussed. This paper presents a quantitative analysis of the comparative antioxidant capacities of foods against various types of ROS.