Theoretical exploration on quenching mechanisms of triplet state riboflavin by xanthone derivatives

Riboflavin (RF), also known as vitamin B2, is an endogenous photosensitizer and much effort has been devoted to finding chemopreventive agents to alleviate the photosensitizing damage of RF. In this communication, the quenching mechanisms of triplet state RF by xanthone derivatives (XD) were explored by means of theoretical calculations. The results indicate that H-atom transfer-based pathway is more probable than direct energy transfer and direct electron transfer pathways to be involved in the triplet state RF quenching by XD, which may be responsible for the chemopreventive activities of XD on RF induced photosensitizing damage.