Influence of the Isolation Method to the Composition and Antimicrobial and Antioxidative Activity of Winter Savory (Satureja montana L.) Essential Oil

Abstract

This research aimed to analyse the chemical composition, as well as the antimicrobial and antioxidative abilities of the Satureja montana L. essential oil. Essential oils were obtained from raw plant material by solvent-free microwave-assisted extraction (WSEO1) and dry plant material by microwave-assisted extraction (WSEO2) and hydrodistillation by Clevenger apparatus (WSEO3). The essential oil composition was determined by gas chromatography/mass spectroscopy analysis (GC/MS), while antioxidative activity was determined by DPPH assay. Antimicrobial activity was characterised by the determination of minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) against Staphylococcus aureus ATCC 25923, Bacillus subtilis ATCC 6633, Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, Proteus vulgaris ATCC 8427 and Klebsiella pneumoniae ATCC 700603. The results indicated that the highest number of different compounds was detected in WSEO2. Aromatic compounds were found to be dominant in WSEO2 and WSEO3 with 47 % and 56 % of total compounds detected, while oxygen-containing monoterpenes with 28 % were dominant in WSEO1. p-Cymene, limonene, cis-sabinene hydrate, carvacrol, thymol and germacrene D were the main compounds present in all essential oil samples. MIC value against all analysed microorganisms was in the range of 1.62-15.52 mg/ml for WSEO1, and 0.20-2.91 mg/ml for both WSEO2 and WSEO3. The EC₅₀ values for WSEO1, WSEO2 and WSEO3 were 3.25, 0.42 and 0.33 mg/ml after 120 min of incubation, respectively. The WSEO2 and WSEO3 showed better antimicrobial and antioxidative activity compared to the WSEO1 probably due to the differences detected in essential oil composition.

Keywords:

• Antimicrobial activity
• antioxidative activity
• essential oil
• GC/MS
• Satureja montana
• solvent-free extraction