Chemical Composition, Total Phenolic Content, and Antioxidant Activity of Salvia officinalis, Satureja hortensis, and Achillea millefolium Essential Oils

Objective: This study investigated the chemical composition, phenolic content, and antioxidant activity of essential oils extracted from three distinct medicinal plants: Salvia spp., Satureja spp. (Satureja hortensis), and Achillea spp. (Yarrow). Methods: : Essential oils were isolated from the aerial parts of each plant using hydrodistillation via a Clevenger apparatus. Gas chromatography-mass spectrometry (GC-MS) was employed for the identification and quantification of volatile compounds. Phenolic content was determined using the Folin-Ciocalteu assay, and antioxidant activity was assessed by measuring the percentage of free radical scavenging capacity against 2,2-diphenyl-1-picrylhydrazyl (DPPH). Results: GC-MS analysis identified α-pinene as a common compound in all three plant species. Salvia essential oil exhibited the highest total phenolic content (8.1 mg gallic acid equivalents [GAE]/mL), while Satureja hortensis had the lowest (4.0 mg GAE/mL). In terms of antioxidant capacity, Salvia essential oil demonstrated the strongest DPPH radical scavenging activity, followed by Yarrow, with Satureja hortensis showing the least effect. Notably, Yarrow essential oil was rich in 1,8-cineole (24.37%) and carvacrol (15.57%), Salvia officinalis contained high levels of camphor (33.60%) and 1,8-cineole (13.83%), and Satureja hortensis was characterized by a predominant presence of carvacrol (54.16%) and γ-terpinene (28.87%). Conclusions: The findings highlight that the essential oils of Salvia officinalis, Satureja hortensis, and Yarrow possess significant phenolic content and antioxidant activity, suggesting their potential application as natural antioxidants in the food and pharmaceutical industries.