Comparative Studies of the Constituents of Fennel Essential Oils extracted from Leaves and Seeds with Those Extracted from Waste Plants after Harvest

To preserve the environment and maximize the utilization of agricultural waste, this work focused on the recycling of residues of fennel plants after harvest The plant materials of the fennel (Foeniculum vulgare var. vulgare) were collected during seasons 2015 / 2016 from Asuit region ( distance from Cairo 320 km) Egypt. The essential oil of the fennel plant was extracted from three stages, the first one was from the green herb in green seed formation stage, the second from the mature fennel seed and the third from the plant waste after harvest. The chemical constituents of fennel (F. vulgare) oils were analyzed by means of GC/MS. The results of the analysis of fennel essential oil showed that thirteen compounds, represent 96.71% of the Egyptian fennel herb essential oil were identified, against fourteen (84.33 %) and thirteen (90.81%) for seed and waste oil, respectively. The major constituents was trans anethole in green herb, dry seeds and waste oil of fennel plant respectively followed by limonene compound in the herb and seeds oil only, while linalool was the second compound in the waste oil. The high percentage of trans anethole was found in the green herb oil (71.5%) followed by the waste (61.5%) and dry seeds oil (45.84%) respectively. Obvious variation in the oil compositions of the three oils due to kind of plant materials of fennel as well as the growth stages was noted. In all cases the essential oils of fennel extracted from green herb, dry seeds or waste characterized by high amount of oxygenated monoterpenes (OMG), which means that the oil extracted from the waste is similar to the oil fennel extracted from green herb and seeds to a large extent.