Chemical Composition and Biological Activity of Essential Oil from Dysphania ambrosioides from Bulgaria

In this article, we report a comprehensive analysis of the chemical composition and biological activity of <i>Dysphania ambrosioides</i> essential oil (DA-EO) originating from Bulgaria. Gas chromatography-mass spectrometry (GC-MS) analysis led to the identification of 53 constituents, revealing a complex phytochemical profile. The results classify the investigated oil as a thymol-carvacrol chemotype, dominated by oxygenated monoterpenes (56.79%), with thymol (19.45%) and carvacrol (14.30%) as the major components. This compositional profile differs markedly from the ascaridole-rich chemotypes commonly reported in the literature. The biological activity of DA-EO was evaluated through its antimicrobial, antioxidant, and anti-inflammatory properties. The oil exhibited broad-spectrum antimicrobial activity against pathogenic microorganisms such as <i>S. aureus</i>, <i>E. coli</i>, and <i>L. monocytogenes</i>. Antioxidant assays (HPSA, HRSA) indicated moderate activity, closely associated with the terpenoid composition of the oil. The anti-inflammatory potential, assessed via inhibition of albumin denaturation (IAD), was analyzed using nonlinear four-parameter (4PL) and five-parameter (5PL) logistic models. The obtained IC₅₀ values (67.0-77.0 µg/mL) were comparable to those of the reference drug ibuprofen, highlighting the significant potential of DA-EO as a natural therapeutic agent.