Fennel (Foeniculum vulgare Mill.) is a widespread perennial umbeliferous (Apiaceae) herb, traditionally
used for medicinal purposes and human consumption. It is highly recommended for diabetes, bronchitis
and chronic coughs, and for the treatment of kidney stones; some of those chronic diseases are related to
the production of radical species involved in the oxidative stress. Therefore, the antioxidant potential of
this herb might explain some of their empirical uses in folk medicine. This is the first time that a systematic
study on different parts of fennel is performed, in order to understand differences in the antioxidant
potential of shoots, leaves, steams, and inflorescences, particularly related to their composition in antioxidant
compounds such as vitamins (ascorbic acid and tocopherols) and phenolics. The shoots seems to
have the highest radical-scavenging activity and lipid peroxidation inhibition capacity (EC50 values
< 1.4 mg/ml), which is in agreement with the highest content in phenolics (65.85 ± 0.74 mg/g) and
ascorbic acid (570.89 ± 0.01 lg/g) found in this part. The shoots also revealed high concentration of tocopherols
(34.54 ± 1.28 lg/g) and were the only part with flavonoids.