Foeniculum vulgare Mill. Aerial Parts (Italian ‘Finocchio di Isola Capo Rizzuto’ PGI): Valorization of Agri-Food Waste as a Potential Source of Lipase Inhibitors and Antioxidants

A large amount of waste material derives from the horticultural industry. These plant matrices constitute a valuable source of active secondary metabolites with a wide spectrum of potential applications, including both human health and veterinary science. Italy is one of the leading European producers of fennel, and the ‘Finocchio di Isola Capo Rizzuto’ is a protected geographical indication (PGI) product, typical of the Calabria region. In this study, the waste material from this PGI Italian fennel was investigated for the first time as a potential source of bioactive compounds. Both bulbs and aerial parts were extracted with ethanol through maceration, and the phenolic content was assessed, together with the antioxidant properties. Moreover, the nutraceutical value was investigated by evaluating the potential anti-obesity effects. To this end, fennel extracts were studied for their inhibitory effects on pancreatic lipase enzyme, which plays a pivotal role in dietary fat absorption. The aerial part extract demonstrated DPPH radical scavenging (IC 50 = 293.13 ± 22.98 µg/mL) and lipid peroxidation inhibitory activities (IC 50 = 43.26 ± 1.90 µg/mL), and it was also effective in inhibiting pancreatic lipase (IC 50 = 3.51 ± 0.09 mg/mL). Moreover, a significant positive correlation was highlighted between observed biological properties and fennel phenolic constituents. Obtained results show that ‘Finocchio di Isola Capo Rizzuto’ PGI by-products are a good candidate for further investigations as a potential source of antioxidant and anti-obesity agents useful as functional ingredients.