DiscussionCarotenoids, which are well-known singlet oxygen quenchers [11], can also scavenge other ROS and RNS. Currently, it is known that the antioxidant properties of the carotenoids in homogenous systems are closely related to their chemical structure, including aspects such as the number of conjugated double bonds, type of structural end-groups, and oxygen-containing substituents [13,17,19].