Determination of optimal harvesting time for essential oil and estragole yield in bitter fennel (Foeniculum vulgare Mill.) growing in culture conditions

• Published in: South African journal of botany Vol. 155; pp. 98 - 102
• Main Authors: Sanli, Arif, Ok, Fatma Zehra
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-04-2023
• Subjects: Bitter Fennel; Essential Oil; Estragole; Foeniculum vulgare Mill; Harvest time; Harvest time; Bitter Fennel; Essential Oil; Foeniculum vulgare Mill; Estragole
• ISSN: 0254-6299; 1727-9321
• DOI: 10.1016/j.sajb.2023.02.012

•Estragole is on the US Environmental Protection Agency High Production Volume Chemicals list.•Bitter fennel is one of the plants with high estragole content.•Cultivation is an important approach in the standardization of essential oil and active ingredient production.•Cultivating of wild bitter fennel plants can affect the content and composition of essential oil.
This study was carried out in order to determine the most suitable harvest period for high essential oil and estragole yield in perennial fennel plants grown under culture conditions. Fennel plants were harvested at 4 different periods, vegetative development (1st and 2nd vegetative stage), pre-flowering stage and full flowering stage with 20-day intervals. Plants were dried in the shade, and essential oils were obtained by Clevenger-type hydro distillation system. Fresh and dry weight, essential oil content, essential oil yield, essential oil components and estragole yield were determined. Harvestings made at the 2nd vegetative and pre-flowering periods had the higher fresh and dry weight. The highest estragole yield were obtained from the pre-flowering period. Essential oil yield was lower in the harvests made in the 1st vegetative period than in other growing stages. Estragole was the main component of fennel essential oil in all growing stages, and the essential oil components differed in terms of number and ratio depending on the stages. In this study, essential oil and estragole production in cultivated perennial fennel plants varied significantly depending on the development stages of the plants, and the most suitable harvesting period in terms of essential oil and estragole yield was the period before flowering.