The globe artichoke landrace “Ortano”: bioactive molecules from by-products cultivation

The globe artichoke [Cynara cardunculus L. var. scolymus (L.) Fiori] is a diploid species (2n = 2x = 34) of the Asteraceae family, native of the European Mediterranean basin. The economic use of the crop includes mainly the consumption of the edible immature flower heads, highly appreciated for their organoleptic and nutraceutical properties. The artichoke cultivation involves the production of a large volume of "waste" such as leaves, stems and roots, sources of several phytochemical compounds with biological activity such as phenols, flavonoids, sesquiterpene lactones, enzymes and prebiotic dietary fibers. Although the health- promoting properties of artichoke extracts, even from non-edible portions of the plant, have been studied, most of the commercial products of pharmaceutical and medical interest are derived from foreign Countries. The present study is part of a project financed by the Lazio Region (POR FESR Lazio 2014-2020) focused on the recovery, characterization and conservation of a globe artichoke landrace at high risk of genetic erosion still cultivated in non-specialized small-holdings in the municipality of Orte (VT, Lazio Region) and therefore named “Ortano artichoke”. In particular, the aim of this study is to investigate the landrace at molecular, morphological and ultrastructural level and to isolate and characterize specific pools of biologically active compounds from different plant organs. Genetic analysis based on SSR (Simple Sequence Repeat) and ISSR (Inter Simple Sequence Repeat) molecular markers confirmed the belonging of “Ortano artichoke” to the “Romanesco” varietal typology, and revealed a high level of genetic variability within this landrace. Indeed, based on 74 plants sampled in the district of Orte, it was possible to distinguish two genetic groups, named Orte 1 and Orte 2. The genotypes belonging to the first group were found closely related to the landraces and clones that represent the varietal platform of the PGI (Protected Geographical Indication) “Romanesco Artichoke of Latium” (Reg. EC n. 2006/2002), while those of the second group were found related to the landrace “Montelupone”, grown in the district of the homonymous municipality in the province of Macerata (MC). The morphological characterization, undertaken using UPOV descriptors, revealed significant differences between the genotypes belonging to the two genetic groups, confirming the complex genetic structure of the “Ortano artichoke” landrace. One representative genotype for each of two distinct genetic groups Orte 1 and Orte 2 was selected for the chemical and biological investigations. The methanolic extracts obtained from four different plant organs (principal and secondary immature flower heads, stems and leaves) of the representative genotypes belonging to the two genetic groups of "Ortano artichoke" were investigated by HPLC-DAD in order to quantify the polyphenolic contents. The results show that caffeoylquinic acids content is the highest in the stems (waste biomass) of both the genotypes with respect to the other plant organs, whereas the highest content of flavonoids was found in the leaves. Antiproliferative, cytotoxic, antimicrobial and antioxidant studies were carried out to determine the biological activities. Different human tumor cell lines were treated in time and dose dependent mode and the obtained EC50 values showed that stems and leaves possess a higher cytotoxic and antiproliferative activity respect to the immature flower heads. A significant selectivity index was found. Slight bactericidal and bacteriostatic activities were detected against environmental bacterial strains and antioxidant properties were also defined by DPPH and ABTS showing that steams of both genotypes had the highest activities. Taken together, the present results confirm that artichoke cultivation could be evaluated as a source of raw material containing molecules with valuable biological activities whose properties can be exploited. The issue of safeguarding agricultural biodiversity and the socio-economic development of the territory through the implementation of a short agri-food chain is of relevance both to enhance national production and to support innovation in the field of pharmaceutical biotechnology and food supplements.