Chemical Profiles and Antimicrobial Activities of Essential Oil From Different Plant Parts of Fennel (Foeniculum vulgare Mill.)

Abstract

The aim of this study was to investigate the chemical composition and antimicrobial activities of essential oils obtained from different organs (leaf, stem, flower, and seed) of Foeniculum vulgare (fennel) plant naturally growing in Sinop province of Turkey. Plant samples collected from the field in 2023 were dried and their essential oils were isolated using the hydro-distillation method with a Clevenger type device. Chemical analyzes were performed simultaneously with GC-FID and GC–MS devices, and component identifications were made with the help of NIST and Wiley libraries. According to the results, estragole (methyl chavicol) was determined as the main component of leaf (51.7%), flower (38.9%) and seed (53.3%) essential oils. Fenchyl acetate (35.3%) was the dominant component in the stem essential oil. In addition, other important compounds such as limonene, fenchon, and γ-terpinene were detected in different proportions. It is thought that these composition differences between organs are due to environmental factors and plant physiology. Within the scope of biological activity studies, the antimicrobial effects of essential oils obtained from each organ against seven Gram-positive and Gram-negative bacteria and two fungi were tested by disk diffusion and minimum inhibitory concentration (MIC) methods. It was observed that Gram-positive bacteria were particularly more sensitive. The highest antibacterial effect was obtained against Staphylococcus aureus with a 30 mm inhibition zone in the seed oil. According to MIC values, the lowest effective concentration was seen on B. cereus, B. subtilis, and S. aureus with 50 μg/mL. No significant effect was observed against A. niger and E. faecalis. This study is the first to reveal the chemical and biological properties of fennel essential oils obtained from different organs in Türkiye.