Evaluation of the Potential of Gracilaria sp. Extract from Gunungkidul, Daerah Istimewa Yogyakarta, as a Natural Sunscreen Agent in BALB/c Mice

Indonesia’s equatorial location, tropical climate, and decreasing ozone layer permeability result in high UV-B radiation exposure, increasing the risk of erythema, burns, edema, and skin cancer. Although sunscreens offer essential protection, many commercial products rely on synthetic ingredients linked to adverse effects such as dermatitis, premature aging, DNA damage, and potential carcinogenicity. Gracilaria sp., a red macroalga abundant in Krakal Beach, Yogyakarta, Indonesia, is a promising natural alternative due to its phytochemical compounds with known antioxidant and UV-B protective properties. This study aimed to identify the bioactive compounds in Gracilaria sp. and to evaluate their antioxidant capacity, sun protection efficacy, physical characteristics in sunscreen spray formulations, and in vivo effects using BALB/c mice. Extraction was conducted via maceration with 70% ethanol. Sunscreen sprays were formulated with extract concentrations of 4000, 6000, and 8000ppm. Analyses included phytochemical screening, total phenolic and flavonoid content, antioxidant activity (percentage inhibition value 80,4%), SPF measurement, physical stability, and in vivo testing. Results confirmed the presence of phenols, flavonoids, alkaloids, and saponins, with total phenolic and flavonoid contents of 11.23 mgGAE/g and 3.95 mgQE/g, respectively. The 8000ppm formulation showed the highest SPF (37,15), meeting Indonesian National Standard (SNI) criteria, while the 6000 pm product achieved SPF 26.75 and demonstrated 0 erythema in vivo, indicating effective UV-B protection. These findings highlight the potential of Gracilaria sp. ethanol extract as a safe, natural UV filter for sunscreen formulations.