Chemical Composition and <i>In Vitro</i> Antimicrobial Activity of the Essential Oil of the Roots of <i>Silene macrosolen</i>

Abstract

Medicinal plants have always played a crucial role as sources for drug lead compounds. Thus, the objective of this study was to qualitatively identify and quantitatively determine the chemical compositions of the essential oil extracted from the roots of Silene macrosolen Steud. ex A. Rich (Caryophyllaceae) and also to quantitatively assay the antimicrobial efficacy of the essential oil against selected medicinally important pathogenic microorganisms. The essential oil was extracted from the root of S. macrosolen by hydrodistillation using Clevenger-type apparatus and analyzed for its chemical compositions by capillary gas chromatography-mass spectrometry (GC-MS). The antimicrobial activity of the oil was evaluated on ten bacterial and three fungal species using the microdilution technique. GC-MS analysis of the essential oil resulted in the identification of 44 compounds that account for 64.63% of the total oil content. The major constituents of the oil were hydrocarbons that include 3,7-dimethyldecane (11.29%), tridecane (9.42%), 4-ethyltetradecane (6.92%), pentadecane (4.90%), and 7-methyl-1-undecene (4.62%). Overall, the oil showed higher antibacterial activities against Gram-positive than Gram-negative bacteria. In particular, the oil exhibited strong activity against Staphylococcus aureus and Staphylococcus epidermidis with an MIC value of 31.5 μg/ml. The results indicate that the essential oil of S. macrosolen roots contains mainly long-chain hydrocarbons which may be responsible for the antimicrobial activity of the plant.