Improvement of the yield and antimicrobial activity of fennel (Foeniculum vulgare Mill.) essential oil by fruit milling

The essential oils of plants have gained great interest in the pharmaceutical industry due to their biological activities. The objective of the present study was to evaluate the influence of fennel (Foeniculum vulgare Mill.) fruit milling on the essential oil yield, chemical composition and antimicrobial activity. The essential oil was obtained from disintegrated and non-disintegrated fruit by Clevenger-type hydrodistillation with hydromodulus 1:10 m/V during 180 min. The essential oil composition was analyzed using gas chromatography-mass spectrometry (GC-MS) technique combined with flame-chromatographic gas-chromatographic detection (GC-FID). Milling impacted the essential oil yield (3.6 +/- 0.3 and 4.0 +/- 0.2 g/100 g of plant material from non-disintegrated and disintegrated fruit, respectively), and quantitative, but not qualitative composition of essential oil. Among fourteen identified compounds, the most abundant in essential oil was trans-anethole (64.87 +/- 0.07% and 69.89 +/- 0.06% from non-disintegrated and disintegrated fruit, respectively). The antimicrobial activity of oil was evaluated using Staphylococcus aureus, Escherichia coli, Proteus vulgaris, Candida albicans, Pseudomonas aeruginosa, Bacillus subtilis, and Klebsiella pneumoniae. The essential oil isolated from disintegrated fruit showed higher antimicrobial activity than the essential oil from non-disintegrated fruit. Among the tested microorganisms, Candida albicans was the most sensitive to the essential oil, followed by Bacillus subtilis.