Formulation of Broad-Spectrum Ultraviolet Protection and Reef-Friendly Sunscreen Containing Perilla Seed Extract

Abstract

The demand for eco-friendly photoprotection has increased due to the observed adverse effects of conventional UV filters on marine ecosystems. In this study, we developed a broad-spectrum, reef-friendly sunscreen emulsion containing Perilla frutescens seed extract. The extraction process was optimized using 95% ethanol maceration for one week, yielding the highest SPF of 22.61. Gas chromatography–mass spectrometry (GC-MS/MS) was used to identify linolenic acid (43.54%) as the predominant fatty acid. Cytotoxicity test results for HaCaT keratinocytes were used to confirm the extract’s safety, with an IC50 of 12.9 mg/mL. The formulated sunscreen met environmental safety standards based on persistence, bioaccumulation, and toxicity (PBT) criteria. A clinical safety evaluation using a 24 h closed patch test (n = 17) demonstrated that the formulation induced no significant alterations in TEWL or erythema levels (p > 0.05), confirming its dermatological safety. In a clinical efficacy evaluation involving 30 volunteers, the formulation containing 1% perilla extract reduced both erythema values and the melanin index, with no statistically significant difference observed (p > 0.05). These findings demonstrate that P. frutescens seed extract is a potent bioactive ingredient for sustainable cosmeceuticals, offering effective sun protection while ensuring safety for both human skin and marine environments.