Carotenoids

Carotenoids are dietary antioxidants,which include lycopene, lutein, and beta-carotene. The sources of these natural free-radical-scavenging compounds include leafy green vegetables, carrots, and tomatoes. Carotenoids have freeradical- scavenging properties and inhibit lipid peroxidation as well [42]. Most studies associated with carotenoids have used them in their oral form. However, there have been reports of the photoprotective effects by topically applied carotenoids [42]. In cell culture study on human skin fibroblasts, there was a decrease in the level of UVB-induced thiobarbituric acidreactive substances by pretreatment with carotenoids. In the study, carotenoids were delivered to fibroblasts through liposomes 20 min prior to UV radiation, and measurements were taken 1 h later [42]. Although carotenoids work best synergistically, by themselves, lycopene was the strongest photoprotectant followed by lutein then beta-carotene [43].

Formulating with these compounds has been tricky since they are pigments and influence the color of the cosmetic in the jar as well as on the skin. However, newer technologies are being developed that are resulting in colorless carotenoids.