Phytochemical and biological profiles of fennel fruits (foeniculum vulgare mill. var. dulce mill.)

The aim of this article is to determine the phytochemical composition and biological activity of sweet fennel fruits, cultivated during two harvest years in Bulgaria (2020 and 2021). First, we researched the chemical composition of fennel fruits and determined their protein content (15.74% and 14.30%), crude fiber (32.88% and 31.50%), ash (6.49% and 7.99%), and mineral elements (58373.22 mg/kg and 102825.96 mg/kg), respectively for 2020 and 2021 harvest years. Then, the fruits were subjected to hydrodistillation and the essential oil was isolated (8.38% and 7.57%), respectively for 2020 and 2021 harvest years. At the end, the lipid fraction was extracted from the ground fruits (9.07% and 5.58%), respectively for 2020 and 2021 harvest years. Polar and unpolar fractions were isolated from the fruits. The results reveal that the fruits of the 2020 harvest have a higher content of protein, essential oil and lipid fraction. Some significant differences were also found in the amounts of macro elements, while the content of micro and toxic elements was comparable. Regarding the chemical composition, both essential oils were high in anethole and low in fenchone. The essential oils of the fennel fruits have antimicrobial activity, which is more pronounced against molds (Aspergillus brasiliensis and Fusarium moliniforme) and yeasts (Candida albicans). The main compounds of polar fraction were saccharides (mono -and di-), followed by sugar alcohols, organic acids, sugar acids, amino acids, and others. In both lipid fractions the main sitosterols are beta-sitosterol and stigmasterol, and major tocopherol is gamma-tocotrienol. Overall, the obtained results demonstrate that with its balanced composition of protein, crude fiber, essential oil, polar and lipid fraction, and mineral elements, the fennel fruits can be used as a supplement to the food of humans and animals.