Protective Effect of Zeaxanthin from Lycium barbarum L. on Ultraviolet B-Induced Skin Photodamage in Mice Through Nrf2-Related Pathway

Ultraviolet (UV) radiation is a predominant cause of skin damage, with UVB leading to more severe harm compared to UVA. <i>Lycium barbarum</i> L. (<i>L. barbarum</i>) is known for its high carotenoid content and has shown great potential in mitigating UVB-induced skin damage. This study investigated the protective effect and mechanism of zeaxanthin from <i>L. barbarum</i> on UVB-damaged skin in BALB/c mice. The results demonstrated that zeaxanthin effectively alleviated the UVB-injured appearance of mouse skin. Histological analyses revealed a reduction in epidermal thickness by 30% and 61% with low and high doses of zeaxanthin, respectively, compared to the model group. Zeaxanthin also inhibited the degeneration of elastic and collagen fibers. Further investigations indicated that the protective mechanism of zeaxanthin was not involved with inflammation suppression. Instead, it activated nuclear factor erythroid 2-related factor 2 (Nrf2) to approximately 3 times the level of the model group, significantly promoting the expression of various antioxidant enzymes and enhancing the total antioxidant capacity of skin tissue, subsequently reducing oxidative stress. Zeaxanthin also downregulated the expression of matrix metalloproteinases, reducing collagen degradation by 35% compared to the model group, which led to improved skin tissue structure and protection against UVB-induced photodamage. These findings provided a theoretical basis for the advanced development and high-value utilization of carotenoids in <i>L. barbarum</i>.