Phytochemical Profiling, Antioxidant, Antibacterial, and Wound Healing Effects of Rosemary Oil Hydrogel

Abstract

Rosmarinus officinalis L., a Mediterranean perennial herb, is well known for its antibacterial, antioxidant, anti-inflammatory, and wound-healing properties. This study investigates the phytochemical profile of R. officinalis, including glycosides, terpenoids, phenols, flavonoids, saponins, alkaloids, and tannins, along with its biological activities. Quantitative analysis revealed  high levels of terpenoids (71.15 ± 0.18 mg/mL), tannins (26.32 ± 0.16 mg TTA/mL), phenolics (8.20 ± 0.001 mg GAE/mL), and flavonoids (0.1874 ± 0.002 mg QE/mL). Gas chromatography–
mass spectrometry (GC-MS) identified a chemotype with low 1,8-cineole (1.77%) and a high concentration of 1,2-hexanediol (67.34%), which may enhance the formulation’s stability and suitability for medicinal and cosmetic applications due to its antimicrobial and humectant properties. The DPPH assay demonstrated strong antioxidant activity with an IC₅₀ value of 21.80 ± 0.56 μg/mL, which is more potent than ascorbic acid (IC₅₀ = 33.79 ± 0.33 μg/mL). Antimicrobial testing using the disc diffusion method showed moderate activity against Staphylococcus aureus (17.33 ± 0.45 mm at 50% concentration) and limited activity against Escherichia coli (12 mm at 50%) compared to gentamicin (24.3 mm and 23.1 mm, respectively). The rosemary oil hydrogel demonstrated a statistically significant improvement in wound contraction (66.87% ± 2.15% by Day 16, p< 0.05) in a Staphylococcus aureus-infected mouse model when compared to negative, placebo, and standard treatment groups. These results support the therapeutic potential of R. officinalis oil hydrogel for topical wound care, combining antimicrobial, antioxidant, and healing
effects in a biocompatible formulation.