Gel Formulations of <em>Syzygium myrtifolium</em> Extract and Nanoparticles: Sunscreen, Antioxidant, and Skin Permeation Activities

Syzygium myrtifolium, commonly known as red shoot leaves, is rich in flavonoids with potent antioxidant and photoprotective activities, underscoring its potential as a natural source for sunscreen development. Gel formulations were prepared by incorporating both the leaf extract and its nanoparticle form, and their sun protection factor (SPF) and antioxidant activities were evaluated. Extracts were obtained via ethanol maceration and subsequently processed into nanoparticles. Both forms were formulated into gels and assessed for physicochemical properties, SPF, antioxidant capacity, and skin permeation. The extract-based gel exhibited superior SPF and antioxidant activity compared to the nanoparticle gel, indicating strong photoprotective potential. These findings highlight S. myrtifolium gel formulations as promising natural photoprotective agents, with extract-based gels emerging as effective sunscreens with antioxidant activity, supporting the development of safer and more sustainable approaches to skin photoprotection.