## 3 Results and Discussion
### Antioxidant Activities and Total Phenolic Content in Different Tissues of Aridchoke Genotypes
Several studies have highlighted significant variation in the antioxidant properties of artichoke, which can be attributed to differences in extraction methods and the plant parts used, including by-products and waste from its cultivation [2 ]. Methanolic extracts from the edible primary heads of two globe artichoke varieties, namely _\"Spinoso Sardo\"_ and _\"Romanesco Siciliano\"_, exhibited antioxidant activities comparable to those observed in the reference genotypes included in the varietal platform of the PGI \"Carcifo Romanasco del Lazio\" in the present study. The antioxidant values for the two varieties were 274.9-467.7, 145.5-287.1, and 530.8-831.3 umol TE/g DW for the DPPH, ABTS, and FRAP assays, respectively [2 ], which, however, were generally lower than those obtained for the \"Carcifo Ortano\" genotypes. On the other hand, DPPH values from the primary and secondary heads in all the genotypes analyzed in this study were very high compared to the value (128 umol TE/g DW) reported by [PERSON] et al. [2 ] for the edible head of Spanish commercial artichoke. [PERSON] et al. [2 ] conducted a comprehensive study demonstrating the radical scavenging activity of the external bracts and receptacle of primary and secondary flower heads from ten different Italian artichoke genotypes using ABTS and DPPH assays. The ABTS values ranged from 21.2 to 146.8 umol TE/g DW and the DPPH values ranged from 12.8 to 204.3 umol TE/g DW, both of which were significantly lower than those that were detected, across the various tissues, in the genotypes analyzed in the present study. The research found that the highest antioxidant activity was detected in the receptacle compared to the external bracts, with average values of 85.7 and 103.8 umol TE g\({}^{-1}\) DW for ABTS and DPPH, respectively, in the receptacle, and 41.9 and 38.3 umol TE g\({}^{-1}\) DW for ABTS and DPPH, respectively, in the external bracts. In contrast to the above, [PERSON] et al. [2 ] revealed a pronounced capacity of ethanol extracts from external bracts to scavenge DPPH radicals compared to the receptacle, with IC\({}_{50}\) values of 6.42 and 28.2 umg/mL respectively. However, the same study also highlighted the exceptional antioxidant capacity of the receptacle, which exhibited a FRAP value of 493.9 umol TE/mL, emphasizing its significant ability to counteract oxidative stress. Additionally, ethanol extracts from the receptacle demonstrated remarkable efficacy in reducing ferric ions, with a value of 527.79 umol Fe\({}^{2+}\) per milligram of dry extract. An interesting study done on artichoke waste has highlighted differences in values obtained with different tests such as FRAP, DPPH and ABTS, in their results it was observed how the same extract shows different values but with the same trend indicating that their antioxidant activity is probably regulated by the same constituents [17]. The correlation analysis was conducted using the results from the four antioxidant assays performed on forty methanolic extracts (10 genotypes \(\times\) 4 tissues) with the Pearson test, to identify which assays produced comparable results and which differed (Table 17). This test calculates the linear correlation coefficient (r), a dimensionless value ranging from \(-\)1 to 1, inclusive, which quantifies the strength and direction of a linear relationship between two datasets. A coefficient closer to either extreme indicates a stronger positive or negative correlation, respectively, while a value of 0 signifies no linear correlation. The highest significant correlation (r = 0.725) was found between the ABTS assay and total polyphenol content (TPC) measured by the Folin-Ciocalteu assay (FC). The FRAP assay also demonstrated a strong correlation with TPC (r = 0.679) and the ABTS assay (r = 0.659). In contrast, the DPPH assay exhibited lower, although significant, correlations with ABTS (r = 0.449), TPC (r = 0.416), and FRAP (r = 0.401). [PERSON] et al.