Antioxidant properties of topical Caulerpa sp. extract on UVB-induced photoaging in mice

, a genus of seaweed native to the Indo-Pacific region, has been known for its antioxidant properties and health benefits when consumed as food. Previous studies have reported 's potential as a strong antioxidant, but its effects on the skin in a topical preparation, especially its role in ultraviolet (UV) protection, have not been studied extensively. Our study investigated the protective effects of 0.2% and 0.4% extract gels on photoaging in the UVB-irradiated skin of mice. The subjects were divided into naive control, vehicle control, and 3 treatment groups (0.2% extract gel, 0.4% extract gel, and 0.02% astaxanthin gel as a standard antioxidant). The groups, except the naive control group, received a total of 840 mJ/cm of UVB irradiation in four weeks. Protective effects of the extract were measured through the evaluation of collagen expression, matrix metalloproteinase (MMP)-1 expression and levels, and 8-OhDG expression. Mice who received topical application of extract gel had higher collagen expression, better-preserved collagen structure, lower levels of MMP-1, and less MMP-1 and 8-OHdG expressions compared to the vehicle control group. There was no difference between different concentrations of the extract. Our findings demonstrated that topical application of extract gel significantly protected UVB-irradiated mice skin from photoaging.