Evaluating a Hybrid Sunscreen Emulsion Enriched with Green Tea and Rose Extracts: Physicochemical, Antioxidant, Antibacterial, and Photoprotective Properties

Sunscreen formulations based on a single class of UV filters may provide insufficient broad-spectrum protection, supporting the development of hybrid systems integrating both organic and mineral photoprotective agents with plant-derived antioxidants. This study developed and characterized an oil-in-water sunscreen emulsion containing three organic UV filters: ethylhexyl methoxycinnamate, bis-ethylhexyloxyphenol methoxyphenyl triazine and diethylamino hydroxybenzoyl hexyl benzoate—in combination with zinc oxide and enriched with aqueous extracts of green tea (Camellia sinensis) leaves and rose (Rosa damascena) petals. The extracts were characterized in terms of total phenolic content. The sunscreen emulsion exhibited satisfactory organoleptic and physical stability throughout the evaluation period, maintaining a homogeneous appearance, a skin-compatible pH (6.97–6.76), and shear-thinning rheological behavior, with only minimal creaming. ATR-FTIR analysis showed a spectral profile consistent with the principal functional groups expected from the formulation components. The extract-enriched emulsion exhibited a higher total phenolic content than the extract-free base (0.191 vs. 0.107 mg GAE/g emulsion) and greater antioxidant activity, with ABTS IC50 values of 36.37 and 43.12 mg/mL, respectively. Spectrophotometric evaluation yielded an in vitro SPF of 14.45 ± 0.18, with a UVA/UVB absorbance ratio of 2.06 and a critical wavelength of 376.4 nm, indicating broad UVA/UVB spectral coverage under the applied experimental conditions. The gravimetric immersion assay showed that 82.14% and 57.14% of the initially applied formulation remained on the PMMA plate after the first and second 20-min water immersion cycles, respectively. Antimicrobial screening revealed selective activity against Gram-positive bacteria, particularly Staphylococcus epidermidis, whereas no inhibition was observed against Escherichia coli, Pseudomonas aeruginosa, or Candida albicans. Overall, the results demonstrate that combining complementary UV filters with green tea and rose extracts can provide a stable, multifunctional sunscreen emulsion with broad UVA/UVB spectral coverage under the applied in vitro conditions, antioxidant potential, favorable application properties, and selective antimicrobial activity.