Different Plant Parts Induce Variances in the Production of Fennel Essential Oil

ABSTRACT Essential oil from fennel plant ( Foeniculum vulgare Mill) is a useful source of natural raw materials due to its biological characteristics; therefore, it is used in the pharmaceutical and food preservation sectors. Plant parts have a major impact on the physiology, metabolism, synthesis and variability of essential oils. The aim of this investigation was to describe the essential oil composition of fennel, which was produced from leaves, umbels, verdant fruits and ripe fruits. It is clear that the highest levels of essential oil output (1.79% or 1.21 g plant −1 ) were produced by ripe fruits, afterwards, verdant fruits (0.79% or 0.30 g plant −1 ), then leaves or umbels (0.24% or 0.10 g plant −1 ). The principal constituents of fennel essential oil that were extracted from different portions were estragole (118.80–964.81 mg 100 g −1 ), limonene (128.02–681.99 mg 100 g −1 ), fenchone (8.16–30.43 mg 100 g −1 ) and γ‐terpinene (18.00–34.01 mg 100 g −1 ); while the majority belonged to the class of oxygenated monoterpenes (130.56–1016.72 mg 100 g −1 ). Essential oil obtained from ripe fruits resulted in the greatest values of major components and major chemical class. This study indicated that differences in fennel essential oil were caused by the subordination of fennel plants to plant parts, and hence, its biological activities were impacted.