Targeting retinal degeneration: zeaxanthin dipalmitate from Lycium barbarum L. prevents A2E photooxidation under blue light.

The accumulation of the toxic byproduct A2E in retinal pigment epithelial cells, coupled with blue-light-induced photooxidation, is a key driver of oxidative damage in early age-related macular degeneration (AMD). Zeaxanthin dipalmitate (ZD), the esterified carotenoid abundant in goji berries, has higher lipophilicity and stability. In this study, ZD was isolated from the berries using its fat-soluble nature and purified using medium-pressure liquid chromatography. Isolated ZD and synthesised A2E were structurally characterised using HPLC, NMR, and positive mode LC-ESI-TQ-MS. An acellular photo-oxidation assay revealed that ZD significantly suppressed A2E degradation under blue light with higher efficacy than vitamin E, a standard antioxidant control. This indicates ZD's potent ability to filter blue light and scavenge reactive oxygen species, mitigating A2E photooxidation and phototoxicity. These findings highlight ZD's unique structural advantages for sustained retinal protection. The findings also support further in vivo and clinical studies of ZD as a natural photoprotective agent that targets early events in AMD.