**5. Antioxidants and inhibition of the UVA-photosensitization reaction**

The following is a summary of typical antioxidants (**Table 1**). Oxygen radicals scavenger (trolox [62], lutein [63], allicin [64], resveratrol [65], isoflavones [66], quercetin [67], catechin [68], theaflavin [69], curcumin [70], chlorogenic acid [71], and superoxide dismutase [72]), singlet oxygen quencher (astaxanthin, histidine [73], and lycopene [74]), hydrogen peroxide scavengers (catalase and glutathione peroxidase), and scavengers for all type of ROS (ascorbic acid [75], ergothioneine [76], L-cysteine, glutathione [77], and tocopherol [78]) are suggested to be effective in suppressing UVA-photosensitization.

However, these antioxidants have not been investigated for the effects of the photosensitizing reaction. Therefore, it is necessary to know if these antioxidants can promote the photosensitizing reaction when coexisting with a photocatalyst, such as riboflavin.
