Chemical Composition of the Essential Oil and Antimicrobial Activity of Aqueous and Methanolic Extracts of Scrophularia Khorassanica

Abstract

In this study, the chemical composition of essential oil from Scrophularia khorassanica obtained by hydro-distillation method was analyzed by GC-MS. Also the antimicrobial activity of aqueous and methanolic extracts was studied on the growth of food pathogenic bacteria including Escherichia coli O157:H , Staphylococcus aureus, Salmonella typhi and some probiotics including Lactococcus lactis, Lactobacillus plantarum and Lactobacillus sakei using micro-dilution method. Result of GC-MS analysis showed that the main components of the essential oil were p-cymene (20.68 %), palmitic acid (11.19 %), thymol (10.21 %), linalool (7.56 %), carvacrol (2.87 %), γ-terpinene (3.15 %) and β-elemene (1.7 %). The minimum inhibitory concentration (MIC) of the extracts ranged between 6.25-50.00 mg/ml. Lb. plantarum and E. coli O157:H were the most sensitive species among the probiotics and pathogenic bacteria. The probiotics were more resistant to the extracts compared to the pathogenic bacteria, so the extracts of S. khorassanica might be used as natural antibacterial agent in food systems especially fermented products including lactic acid bacteria.

Key words:

• Scrophularia khorassanica
• antimicrobial activity
• probiotic bacteria
• p-cymene