Evaluation of chemical composition and biological activity of essential oil of Origanum vulgare L. ssp. Glandulosum

The Origanum vulgare L. ssp. glandulosum (Desf.), commonly known as glandular oregano, is a perennial herbaceous plant belonging to the Lamiaceae family. It is characterized by quadrangular, often branched stems, and opposite, oval to elliptical leaves rich in glandular structures. The flowers, ranging from pink to purple, are grouped in compact terminal inflorescences. This subspecies is endemic to Mediterranean regions, particularly Algeria and Tunisia, where it naturally grows in dry and sunny environments. It is valued for its strong aroma and medicinal properties, mainly attributed to the richness of its essential oil.

This study of plant aimed to evaluate the chemical composition and antibacterial and antioxidant activities of the essential oil extracted from O. vulgare ssp. glandulosum. Chemical analysis using gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS) identified 43 compounds representing 98.55% of the oil. The major constituents were para-cymene (25.615%), thymol (23.129%), and carvacrol (20.321%).

Antibacterial activity of essential oil of Origanum vulgare L.ssp. Glandulosum was assessed using the disk diffusion method by measuring inhibition zones and broth microdilution to determine minimum inhibitory concentrations (MIC). Results showed significant antimicrobial effects. Antioxidant activity was evaluated via the DPPH radical scavenging assay, demonstrating moderate antioxidant potential with an IC₅₀ value of 461.62 μg/ml.