## 3 Discussion
### Chemical Composition  
The quantitative and qualitative polyphenol profile in artichoke leaf extracts is extensively documented in the literature, indicating that it depends on various factors, including the extraction and determination methodologies, genotype, environmental conditions, agronomic practices, and specific physiological stage of the analyzed leaf material [13; 15; 36; 37; 38; 39]. In this study, the total phenolic content, calculated as the sum of individual phenolic compounds, differed significantly among the three analyzed genotypes, ranging from 6.882 to 16.814 g/kg DW, with the two \"Carcifo Ortano\" genotypes showing the highest values. [PERSON] and coworkers [13], by analyzing several clones selected from the two Sicilian landraces \"Spinoso di Palermo\" and \"Violetto di Sicilia\", reported lower values in the range of 2.195-8.466 g/kg DW compared to those obtained in this study, in particular for the \"Carcifo Ortano\" genotypes. These differences could be attributed to the diverse investigated genotypes and to the different extraction conditions used for the recovery of the phenolic compounds. In our investigation, an ultrasound-assisted method was employed, in contrast to conventional methodologies reliant on shaking plant material with alcoholic solvents. Ultrasound typically enhance the extraction of bioactive compounds by leveraging the cavitational effect, thereby promoting the liberation of extractable compounds and augmenting mass transport through diffusion or by disrupting plant cell walls [37]. On the other hand, [PERSON] et al. [39] documented higher values for the phenolic content, as the sum of clorogenic acid, cyanin, luteolin and apigenin, in artichoke leaf extracts, ranging from 11.7 to 22.8 g/kg DW, within three seed propagated hybrids (\"Tempo\", \"Opal\" and \"Madrigal\") and two landraces from the Puglia region (\"Violetto di Foggia\" and \"Brindisino\"). Apart from the different genotypes analyzed, the observed differences can likely be attributed to the age and positioning of the leaf material analysed in our study, where a bulk of leaf biomass was deliberately sampled from artichoke plants after the harvesting of flower heads, in contrast to the referenced study, which focused on the 2-3 leaves borne by flower stems. As evidence of these differences, [PERSON] et al. [40] documented that the top-positioned leaves of the artichoke plant represent a better source of polyphenol compounds compared to the basal ones. Despite the broader range of variations reported in the literature regarding the phenolic content of artichoke by-products, the level of total phenolic compounds found in the leaf waste of \"Carcifo Ortano\" underscores its potential as a cost-effective and promising reservoir of bioactive compounds. In accordance with information available in the literature [17; 41; 42; 43], our study identified caffeoylquinic acids as the predominant phenolic compounds in artichoke leaf extracts. However, significant variations were observed among the three examined genotypes, with the proportions for the phenolic acids representing 91.5%, 75.0%, and 52.7% of the total phenolic compounds in Orte 2, Orte 1, and Grato 1 leaf extracts, respectively. Conversely, significantly lower relative amounts of caffeoylquinic acids, ranging from 0 to 46.2%, were reported in the previously mentioned study of [PERSON] et al. [13], in which leaf samples from different clones of the \"Spinoso di Palermo\" and \"Violetto di Sicilia\" landraces were considered. Among caffeoylquinic acids, 5-O-caffeoylquinic acid (chlorogenic acid) and 1,5-di-O-caffeoylquinic acid were the most abundant in the three genotypes analysed.