Phytochemical profile and in vitro bioactivities of the Italian tomato landrace Riccio di Parma

Solanum lycopersicum L. var. Riccio di Parma (Solanaceae family) is an Italian tomato landrace, first cultivated in 1867 in the Parma countryside, but gradually abandoned in the 1950s by the canning industry. This variety is characterized by its irregular shape, deep grooves, bright red color, green shoulder, and high resistance to drought and cryptogamic diseases; moreover, it is cultivated through dry farming techniques without irrigation, reducing the risk of contamination. In the attempt to valorize this local species and to highlight a possible interest in terms of safety and nutraceutical properties, a phytochemical and biological characterization of Riccio tomato and its byproducts, provided by La Sbecciatrice company (Caserta, Campania), was performed within the project “ON Foods – Research and innovation network on food and nutrition Sustainability, Safety and Security – Working ON Foods”, funded by the European Union – NextGenerationEU. To this end, whole tomatoes (T), tomato sauce (TS), and tomato waste (TW), collected over two harvesting years, i.e., 2022 and 2023, were freeze-dried and subjected to Bligh-Dyer extraction obtaining two different organic (O) and hydroalcoholic (HA) extracts for further analysis. The samples underwent a multimethodological phytochemical analysis, based on untargeted (NMR, ESI FT-ICR MS) and targeted (UV-Vis, HPLC-MS, ICP-OES) methodologies. Moreover, a screening of bioactivities associated to the polyphenol content, including antioxidant, chelating, reducing, and antiglycative as well as the cytotoxicity on human cell lines, both cancerous and noncancerous (e.g. pancreatic Bx-PC3 cancer cells and HFF-1 fibroblasts). Cytoprotection by nontoxic samples towards the oxidative damage induced by tert-butyl hydroperoxide (tBOOH), in term of cell viability and intracellular ROS (reactive oxygen species) levels, was evaluated too. HPLC-MS/MS analysis highlighted the presence of 11 polyphenols in HA extracts. Chlorogenic acid, rutin, and naringenin were identified and quantified as the most abundant polyphenols in T23 relative to T22, while the opposite trend was observed in tomato waste. Regarding hydroxycinnamoylquinic acids, they were found in similar quantities in TS22 and TS23, while flavonoids were more expressed in TS22 with respect to TS23. Moreover, the extracts were found endowed with chelating abilities towards ferrous and ferric ions, although with different potency and efficacy. T22 and T23 HA extracts were the most effective as ferric ion chelators, followed by sauce and waste, despite lower ferrous ion chelating abilities. O extracts from 2023 harvest exhibited marked ferrous ion chelating effects, whereas those from 2022 harvest, were more effective as ferrous ion chelators. All the samples were well tolerated by HFF-1 cells, except for T22 and TS22 O extracts and T23 HA extract, which significantly reduced cell viability at concentrations higher than 100 µg/ml. A marked cytotoxicity was also produced by the organic extracts in BxPC3 cancer cells; particularly, T22 O extract hindered the cell viability by about 45% at 50 µg/ml, although the effect was lower than that of doxorubicin. The extracts counteracted tBOOH-induced oxidative stress, with potency varying by extract type and product. Further studies are needed to confirm these findings, clarify the mechanisms, and verify the bioactivities of Riccio tomato extract in other experimental models.