Impaginato 23 Adv. Hort. Sci., 2019 33(1): 23-31 DOI: 10.13128/ahs-23015 Biochemical characterization of arti- choke (Cynara cardunculus var. scolymus L.) spring genotypes from Marche and Abruzzo regions (Central Italy) A. Galieni, 1 (*) F. Stagnari 2, M. Pisante 2, C. Platani 1, N. Ficcadenti 1 1 Centro di Ricerca Orticoltura e Florovivaismo, CREA, Via Salaria, 1, 63077 Monsampolo del Tronto (AP), Italy. 2 Facoltà di Bioscienze e Tecnologie Agroalimentari e Ambientali, Università degli Studi di Teramo, Via R. Balzarini, 1, 64100 Teramo, Italy. Key words: antiradical activity, artichoke genotypes, capitula quality traits, total phenolic content. Abstract: Ten artichoke genotypes from Marche and Abruzzo Regions [Ascolano (As), Castorano (Cs), Clone Monsampolo, Jesino (Je), Mazzaferrata (Mz), Montelupone A, Montelupone B, Urbisaglia1 (Ub_1), Urbisaglia2 and Violetto Tardivo di Pesaro] were characterized for their quality traits and peculiar end- use attitudes, in comparison with the reference Romanesco Clone C3 (Cl_C3). Total polyphenols content (TPC), total flavonoid content (TFC) and antiradical activity were assessed in the receptacle and external bracts of both main and first order capitula. Cl_C3 showed high TPC and TFC values in the receptacle of the main flower heads (7.4 mg gallic acid equivalents, GAE, g-1 dry weight, DW, and 3.6 mg rutin equivalents, RUE, g-1 DW, respectively), confirming its attitude for fresh consumption. Je and Ub_1 showed great and stable (among main and first order capitula) head quality, highlighting their potential for breeding pro- grams to enhance the content of functional compounds. Conversely, Mz and As could be appreciable for processing or pharmaceutical applications, being char- acterized by great TPC (external bracts, first order capitula: 2.8 and 2.7 mg GAE g-1 DW, respectively) and TFC (external bracts, first order capitula: 2.1 and 2.7 mg GAE g-1 DW, respectively) values in the waste parts. High correlations between TPC and TFC with antiradical activity were also observed. Our results suggest the possibility to promote the utilization in genetic breeding programs of the autochthonous artichoke populations, according to their peculiar charac- teristics, including also their biochemical composition. 1. Introduction Globe artichoke [Cynara cardunculus L. var. scolymus (L.) Fiori] belongs to the family of Asteraceae (Compositae) and it is an herbaceous perenni- al crop mainly cultivated in the Mediterranean Basin (about 65% of world production) followed by Americas and China (Sihem et al., 2015, Lombardo et al., 2017). In Italy it plays an important role in the agro-food (*) Corresponding author: angelica.galieni@crea.gov.it Citation: GALIENI A., STAGNARI F., PISANTE M., PLATANI C., FICCADENTI N., 2019 - Biochemical characteri- zation of artichoke (Cynara cardunculus var. scolymus L.) spring genotypes from Marche and Abruzzo regions (Central Italy). - Adv. Hort. Sci., 33(1): 23-31 Copyright: © 2019 Galieni A., Stagnari F., Pisante M., Platani C., Ficcadenti N. This is an open access, peer reviewed article published by Firenze University Press (http://www.fupress.net/index.php/ahs/) and distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Competing Interests: The authors declare no competing interests. Received for publication 9 April 2018 Accepted for publication 12 December 2018 AHS Advances in Horticultural Science http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/ Adv. Hort. Sci., 2019 33(1): 23-31 24 chain with over 43.8 Kha and approximately 366 Kt of floral heads produced (FAO, 2016). The Italian gene pool of globe artichoke includes hundreds of varieties and ecotypes, grouped into four main types i.e. “Catanesi”, “Romaneschi”, “Spinosi” and “Violetti”. According to the harvesting period, they are classified as early or late distinct clonal varietal groups, with the former having a typi- cal autumn-winter cycle in the southern Regions, while late including spring genotypes mainly grown in central Regions (Ciancolini et al., 2013 a, b). The vari- etal constitution of artichoke is restricted to clonal selection carried out within local populations propa- gated by agamic way which represent a patrimony of agrobiodiversity and a biological, cultural and eco- nomic heritage (Ficcadenti et al., 2013). However, several cases of homonymy and synonymy (different varieties are called with the same name in the first case, while the same variety comes call with different names in the second) as well as unsatisfactory, uni- formity and identity of accessions occur (Ficcadenti et al., 2013). Traditional agricultural and food pro- duction must be safeguarded to avoid processes of globalization and homologation and, consequently, identification, collection, characterization and con- servation of agrobiodiversity as well as development of genetic improvement strategies, particularly linked to nutritional and organoleptic traits, have been undertaken in these years (Mauromicale and Ierna, 2000; Ficcadenti et al., 2010; Ciancolini et al., 2012). Recently, a renewed and growing interest for arti- choke cultivation has been observed worldwide mainly due to its potential uses as functional food: its large immature inflorescences, called capitula or heads, represent a rich source of bioactive com- pounds - including polyphenols with a strong antirad- ical activity (Schütz et al., 2004) - inulin, fibres and minerals (Lattanzio et al., 2009; Lombardo et al., 2010; Pandino et al., 2011). Furthermore, the utiliza- tion of by-products of artichoke processing (i.e. external bracts) involves animal feedstuff (Megías et al., 2002) or extraction of functional molecules (Larossa et al., 2002). It emerges that the types and amount of bioactive substances and their activity (i.e. polyphenols content and the related antioxidant activity) could be used to characterize and select spe- cific genotypes. Nowadays, only few studies have investigated on polyphenols content, discriminating among the dif- ferent head parts of artichoke (see for example F r a t i a n n i e t a l . , 2 0 0 7 ; L o m b a r d o e t a l . , 2 0 1 0 ; Soumaya et al. 2013; Sihem et al., 2015); besides, the simultaneous determinations of total polyphenols and flavonoids content with radical scavenging capa- bility, have not been considered at all. Consequently, in the present work we aimed at investigating such important biological properties in eleven spring accessions of artichoke collected in Central Italy (Marche and Abruzzo regions). The primary objec- tives were to obtain a preliminary: (i) genotype’s characterization of the selected Central-Italy arti- choke accessions from a biochemical point of view; (ii) evaluation of the suitability of the selected arti- choke genotypes for fresh consumption or by-prod- ucts production. 2. Materials and Methods Plant material, management practices and head sam- pling The study was carried out in 2014 at the experi- mental field of the Research Centre for Vegetable and Ornamental Crops, Council for Agricultural Research and Economics (CREA-OF), located in Monsampolo del Tronto (AP) (latitude 42°52’59.1” N, longitude 13°48’01.9” E), in the coastal area of the Marche Region (Central Italy) a typical area for globe artichoke cultivation. T e n a r t i c h o k e a c c e s s i o n s f r o m M a r c h e a n d Abruzzo Regions, named as “Clone Monsampolo” (Cl_MSP), “Ascolano” (As), “Castorano” (Cs), “Jesino” (Je), “Mazzaferrata” (Mz), “Montelupone A” (ML_A), “Montelupone B” (ML_B), “Urbisaglia1” (Ub_1), “Urbisaglia2” (Ub_2) and “Violetto Tardivo di Pesaro” (VT_PS), were collected on the base of their peculiar sensory features and were compared with the refer- ence genotype “Romanesco Clone C3” (Cl_C3), char- acterized by high market standards of the flower heads (purple with green shades, round shape, regu- lar size and thick consistency). The selected globe artichoke genotypes differ for their biological and morphological profiles, as briefly synthetized in Table 1. Plant material (shoots, named “carducci”) was transplanted in August 2011 in rows spaced 1.00 m apart with row spacing of 1.20 m; each plot (arti- choke genotype) consisted of thirty plants. The fertil- ization program, typical of the area, consisted in: 150 kg ha-1 of N, 80 kg ha-1 of phosphorus pentoxide (P2O5) and 100 kg ha-1 of potassium oxide (K2O), respectively. The experimental field was kept weed- free by mechanical weed control and no pest control was needed. Galieni et al. - Biochemical differences among artichoke genotypes 25 At the marketing stage, six capitula per artichoke genotype were harvested, without floral stem, in two subsequently times (10th April and 10th May, consid- ered as early and mid-spring), allowing to compare both main (first sampling data) and first order (sec- ond sampling data) capitula. Each flower head was separated into ‘external bracts (∼15 bracts)’ (waste part) and ‘receptacle’ (edible fraction), freeze-dried, homogenized and stored at -20°C until biochemical characterization. Chemical analysis The extraction of polyphenols and flavonoids were carried out as described by Gouveia and Castilho (2012 a). The Folin-Ciocalteu reagent method was used to evaluate the total polyphenols content (TPC) of the external bracts and receptacle following the method of Gouveia and Castilho (2011). Plant extracts were dissolved in methanol (10 mg mL-1); aliquots of 50 µL were added to 1.25 mL of Folin-Ciocalteu (dilution, 1:10) and 1.0 mL of a 7.5% Na2CO3 solution. Solutions were maintained at room temperature for 30 min and the TPC was determined at 765 nm using a Beckman DU640B spectrophotometer (Beckman Coulter, Brea, California, USA). Gallic acid standard solutions were used to calibrate the method, so results were expressed as mg gallic acid equivalents (GAE) per g-1 dry weight (DW). Total flavonoids content (TFC) was calculated fol- lowing the procedure described by Gouveia and Castilho (2012 a) and estimated as rutin equivalents (RUE), i.e. expressed as mg RUE g-1 DW. Methanolic solutions (500 µL of sample solution) of the plant extracts (2.5 mg mL-1) were mixed with 1.5 mL of methanol, 2.8 mL of water, 100 µL of potassium acetate (1 M) and 100 µL of aluminium chloride (10% in methanol). The absorbance of reaction mixture was read after 30 min at room temperature and at 415 nm using a Beckman DU640B spectrophotome- ter. The radical scavenging activity of the extracts was determined using the stable radicals: (i) 2,2’-azino- b i s ( 3 - e t h y l b e n z o t h i a z o l i n e - 6 - s u l p h o n i c a c i d ) - TEAC/ABTS assay (ABTS) (Re et al., 1999), modified as described by Gouveia and Castilho (2012 a); and (ii) 2,2-diphenyl-1-picrylhydrazyl - DPPH assay (Gouveia and Castilho, 2012 b). In each assay, Trolox was employed as reference standard and results were expressed as µmol Trolox equivalent (TE) g-1 DW. Reagents and solvents were purchased from Sigma Chemicals Co. (St. Louis, MO). All reagents were of analytical grade. Statistical analysis In order to test (F-test) the effect of genotype on all the investigated variables, a one-way analysis of variance (ANOVA) was performed. The experiment was conducted following a complete randomized design and each sampled capitula represented a sin- gle repetition. When significant differences were detected, the means were compared based on the standard error of the difference (SED) between means, with significance being assigned using the least significant difference (LSD) value at the 5% (p<0.05) level of significance. Before the ANOVA, the d a t a w e r e a n a l y z e d t o t e s t f o r n o r m a l i t y a n d homoschedasticity assumptions, through graphical methods. To interpret and summarize the association between treatments (artichoke genotypes: Cl_C3, Cl_MSP, As, Cs, Je, Mz, ML_A, ML_B, Ub_1, Ub_2 and VT_PS) and variables (TPC, TFC, ABTS, DPPH) the principal component analysis (PCA) was applied. The PCA was performed separately for main and first order capitula; each principal component (PC) was Table 1 - Head characteristics of the eleven selected genotypes of globe artichoke Genotype Acronym Colour of outer bracts Colour of inner bracts Bracts "Clone C3" Cl_C3 Green with Purple shades Yellow Spineless "Clone Monsampolo" Cl_MSP Green Yellowish-green Spineless "Ascolano" As Purple with green shades Yellow-greenish with purple shades Spineless "Castorano" Cs Purple with light green shades Yellow-purple Spineless (but mucronate) "Jesino" Je Purple with Green shades Yellow purple Spineless "Mazzaferrata" Mz Purple with Green shades Yellow-greenish Spineless "Montelupone A" ML_A Purple with Green shades Yellow-purple Spineless "Montelupone B" ML_B Purple with Green shades Yellow-purple Spineless (but mucronate) "Urbisaglia 1" Ub_1 Purple Yellow-purple Spineless "Urbisaglia 2" Ub_2 Purple Yellow-purple Spineless "Violetto tardivo PS" VT_PS Purple Yellow-purple Spine Adv. Hort. Sci., 2019 33(1): 23-31 26 calculated as a linear combination of the standard- ized original variables by using the eigenvectors of the correlation matrix. The results were visually explored in a two-dimensional PCA correlation bi- plot: standardized PC1 and PC2 scores were plotted as symbols, while the correlations between PCs and standardized variables (factor loadings) were plotted as vectors. Statistical analyses were performed with the R software (R Core Team, 2017). 3. Results and Discussion The TPC and TFC in the receptacle and external bracts of main and first order capitula of the eleven artichoke genotypes, are reported in Table 2. TPC ranged from 1.5 to 9.2 mg GAE g-1 DW, while TFC ranged from 1.8 to 4.1 mg RUE g-1 DW, matching with the literature data or, in some circumstances, result- ing slightly higher (Lombardo et al., 2010; Pandino et al., 2011; Gouveia and Castilho, 2012 a; Pandino et al., 2012 a; Sihem et al., 2015; Dabbou et al., 2017; Marques et al., 2017; Petropoulos et al., 2017). Both traits were significantly (p<0.05) influenced by geno- type: differences are related to both head part (receptacle or external bracts) and their location on plant architecture (main or first order capitula) (Table 2). Clear trends were observed: Je gave the highest TPC content (5.1 mg GAE g-1 DW, averaged over head parts and harvest time), followed by Ub_1, Ub_2 and VT_PS (5.0, 5.0 and 4.3 mg GAE g-1 DW on average, respectively), while Cl_MSP resulted as one of the worst genotypes in terms of polyphenols concentra- Table 2 - Total polyphenols content [TPC, mg gallic acid equivalents (GAE) g-1 dry weight (DW)] and total flavonoids content [TFC, mg rutin equivalents (RUE) g-1 DW] in the receptacle and in the external bracts of different artichoke genotypes Genotype§ Main capitula First order capitula TPC (mg GAE g-1 DW) TFC (mg RUE g-1 DW) TPC (mg GAE g-1 DW) TFC (mg RUE g-1 DW) Receptacle Cl_C3 7.4 ± 0.11 3.6 ± 0.23 3.8 ± 0.57 2.5 ± 0.38 Cl_MSP 3.6 ± 0.28 1.9 ± 0.16 3.1 ± 0.09 1.9 ± 0.12 As 5.7 ± 0.42 2.4 ± 0.21 3.9 ± 0.55 2.2 ± 0.19 Cs 6.3 ± 0.91 2.5 ± 0.30 2.6 ± 0.03 1.9 ± 0.08 Je 8.2 ± 1.09 3.3 ± 0.44 5.4 ± 0.47 3.0 ± 0.34 Mz 4.9 ± 0.73 2.8 ± 0.17 6.8 ± 1.35 3.5 ± 0.61 ML_A 5.8 ± 1.34 4.1 ± 1.01 2.1 ± 0.19 1.8 ± 0.19 ML_B 4.3 ± 0.22 2.3 ± 0.31 4.0 ± 0.64 3.1 ± 0.66 Ub_1 8.0 ± 0.58 3.4 ± 0.36 4.7 ± 0.66 2.9 ± 0.69 Ub_2 9.2 ± 1.55 3.9 ± 0.74 4.4 ± 0.15 2.6 ± 0.15 VT_PS 6.8 ± 0.45 3.5 ± 0.42 4.2 ± 0.45 3.2 ± 0.45 F-test ** * ** * SED 1.2 0.7 0.9 0.6 External bracts Cl_C3 3.2 ± 0.12 2.6 ± 0.07 2.1 ± 0.06 2.3 ± 0.18 Cl_MSP 2.2 ± 0.15 2.0 ± 0.00 1.7 ± 0.11 2.0 ± 0.10 As 3.0 ± 0.19 2.4 ± 0.08 2.7 ± 0.42 2.7 ± 0.30 Cs 2.9 ± 0.28 2.1 ± 0.17 2.1 ± 0.04 2.6 ± 0.20 Je 3.9 ± 0.53 2.5 ± 0.18 3.0 ± 0.46 2.9 ± 0.56 Mz 2.4 ± 0.14 2.5 ± 0.08 2.8 ± 0.16 2.1 ± 0.04 ML_A 2.1 ± 0.25 2.4 ± 0.25 1.5 ± 0.08 2.3 ± 0.02 ML_B 2.1 ± 0.16 2.0 ± 0.07 2.2 ± 0.28 2.3 ± 0.28 Ub_1 4.8 ± 0.30 2.9 ± 0.17 2.4 ± 0.03 2.3 ± 0.22 Ub_2 4.1 ± 0.61 2.7 ± 0.25 2.2 ± 0.19 2.3 ± 0.02 VT_PS 4.0 ± 0.11 3.2 ± 0.05 2.2 ± 0.05 3.0 ± 0.21 F-test ** ** ** NS SED 0.4 0.2 0.3 Data refer to both main and first order capitula (two different harvest times, at early and mid-spring 2014). Means ± standard errors of n=6 independent replicates are reported. * p<0.05; ** p<0.01; *** p<0.001; NS = not significant. SED, standard error of differences between means. § The list of the used acronomys is reported in Table 1. Galieni et al. - Biochemical differences among artichoke genotypes 27 tion in artichoke heads (on average 2.7 mg GAE g-1 DW) together with ML_A and ML_B (on average 2.9 and 3.2 mg GAE g-1 DW, respectively) (Table 2). These results were quite confirmed by TFC data (Table 2), indicating those genotypes’ suitable for fresh con- sumption rather than food processing. Lower antioxi- dant compounds (i.e. polyphenols) is, indeed, consid- ered a qualitative trait required by industry, thanks to the scarce propensity to enzymatic browning phe- n o m e n a a f t e r c u t t i n g a n d s t o r a g e o p e r a t i o n s (Lattanzio et al., 1994; Lombardo et al., 2010). The reference genotype (Cl_C3) confirmed its high value for fresh consumption, registering higher TPC and TFC, only in the combination early-spring harvest (main capitula)/receptacle (Table 2), mostly appreci- ated by consumers and with the highest commercial value. As previously observed (Fratianni et al., 2007; Lombardo et al., 2010; Pandino et al., 2011; Pandino et al., 2012 b; Pandino et al., 2013 a; Sihem et al., 2015), polyphenols were not uniformly distributed in the different floral head parts (Fig. 1): regardless of the harvest time, higher TPC values were observed in the receptacle (5.2 mg GAE g-1 DW, averaged over genotypes) while lower in the external bracts (2.7 mg GAE g-1 DW, averaged over genotypes). Besides, no differences emerged in terms of TFC (2.5 vs. 2.8 mg GAE g-1 DW in external bracts and receptacle respec- tively, averaged over genotypes). The different amount of antioxidant compounds in the various head parts is of interest to identify genotypes rich in these molecules in the by-products (external bracts) and hence interesting for the industrial processes (i.e. animal feedstuff, fiber production, recovery of func- tional ingredients) (Femenia et al., 1998; Larossa et al., 2002; Megías et al., 2002; Lattanzio et al., 2009). Nonetheless, we observed some differences in terms of relative TPC among artichoke accessions, with par- ticular regards in terms of relative TFC (Fig. 1): the genotypes Cl_MSP, As and Cs were characterized by the highest relative TFC in the waste products (Fig. 1), suggesting useful utilization for the by-products processes, with external bracts representing a poten- tial innovative source for flavonoid extraction. Lastly, TPC values lowered in both receptacle and external bracts shifting from main to first order capit- ula (Fig. 2A); this trend was confirmed by all the accessions with the exception of Mz (Fig. 2A), which gave the highest TPC values in the first order flower heads (Table 2), so maintaining a high content of functional compounds during the growing cycle. A similar behavior was recorded for some of the select- ed artichoke accessions in terms of TFC (see for exam- ple Cl_MSP, As and ML_B) (Fig. 2B). This was probably attributable to the environmental conditions record- ed during the harvest season. Despite the solar radia- tion levels show the stronger effect on polyphenols accumulation in the artichoke’ receptacle (Pandino et al., 2013 b), in our study the lower temperatures observed in April (-10% on average with respect to May - considering the mean air temperatures record- ed during the first 10 days of each month) could have affected TPC and TFC, as previously observed in other crops (Klimov et al., 2008; Hykkerud et al., 2018). Fig. 1 - Relative proportion (as percentage) of total polyphenols content [TPC, gallic acid equivalents (GAE) g-1 dry weight (DW)] and total flavonoids content [TFC, mg rutin equiva- lents (RUE) g-1 DW] in the receptacle and external bracts averaged over both main and first order capitula of diffe- rent globe artichoke genotypes (see Table 1 for the list of acronyms). Data represent means ± standard errors, n=12 independent replicates. Fig. 2 - Variations normalized to main capitula values (dashed line) of (A) total polyphenols content [TPC, mg gallic acid equivalents (GAE) g-1 dry weight (DW)] and (B) total fla- vonoids content [TFC, mg rutin equivalents (RUE) g-1 DW] in the receptacle and external bracts of different globe a r t i c h o k e g e n o t y p e s ( s e e T a b l e 1 f o r t h e l i s t o f acronyms). Data represent means ± standard errors, n=6 independent replicates. 28 Adv. Hort. Sci., 2019 33(1): 23-31 Radical scavenging activity (ABTS and DPPH assays) registered differences among thesis similar to those observed for TPC and TFC data (Table 3). ABTS values ranged from 21.2 to 146.8 µmol TE g-1 DW and DPPH ranged from 12.8 to 204.3 µmol TE g-1 DW, showing the same order of activity previously found in other antioxidant capacity assays on artichoke (Gouveia and Castilho, 2012 b; Rouphael et al., 2017). The highest activity was concentrated in the recepta- cle (85.7 and 103.8 µmol TE g-1 DW for ABTS and DPPH, respectively vs. 41.9 and 38.3 µmol TE g-1 DW for ABTS and DPPH, respectively in the external bracts) regardless of genotype and harvesting time (Table 3) (Sihem et al., 2015). Also for these bio- chemical traits, Je, Ub_1 and Ub_2 ranged at the first positions while Cl_MSP as the genotype with the low- est ABTS and DPPH values (Table 3). Moreover, we found significant (p<0.001) linear relationships between these variables, confirming previous results (Alghazeer et al., 2012; Lombardo et al., 2013). Follows the higher measured Pearson’s correlation coefficients: TPC vs. ABTS, r=0.84; TPC vs. DPPH, r=0.91; TFC vs. ABTS, r=0.76; TFC vs. DPPH, r=0.81. Indeed, phenolic compounds are known to have the ability to block the chain reaction of reactive oxygen and nitrogen species through different pathways involving (i) direct reaction with free radicals, (ii) sequester metal ions able to spread the chain reac- tion, (iii) synergic action with other antioxidants (Khasawneh et al., 2014). The relationships between TPC, TFC, ABTS and DPPH, classified based on the analysed capitula parts Table 3 - Radical scavenging activity (µmol trolox equivalents (TE) g-1 DW) obtained from two different assays: trolox equivalent antioxi- dant capacity with 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) in the receptacle and in the bracts of different artichoke genotypes Data refer to both main and first order capitula (two different harvest times, at early and mid-spring 2014). Means ± standard errors of n=6 independent replicates are reported. * p<0.05; ** p<0.01; *** p<0.001; NS = not significant. SED, standard error of differences between means. § The list of the used acronomys is reported in Table 1. Genotype§ Main capitula First order capitula ABTS (µmol TE g-1 DW) DPPH (µmol TE g-1 DW) ABTS (µmol TE g-1 DW) DPPH (µmol TE g-1 DW) Receptacle Cl_C3 146.8 ± 6.91 165.5 ± 7.75 61.1 ± 14.29 61.3 ± 26.77 Cl_MSP 71.3 ± 8.85 47.3 ± 12.82 42.3 ± 7.39 31.7 ± 2.95 As 87.2 ± 14.10 109.9 ± 14.97 73.4 ± 7.23 78.2 ± 14.87 Cs 97.4 ± 28.90 127.2 ± 31.56 34.4 ± 5.83 33.5 ± 7.20 Je 119.5 ± 19.14 185.6 ± 34.58 76.0 ± 12.66 56.9 ± 11.52 Mz 86.6 ± 19.63 108.4 ± 28.80 95.0 ± 12.93 178.2 ± 42.51 ML_A 104.2 ± 32.54 144.8 ± 57.25 31.4 ± 3.08 26.2 ± 9.39 ML_B 68.2 ± 8.77 80.0 ± 12.90 82.3 ± 19.76 47.2 ± 12.23 Ub_1 140.3 ± 16.58 171.5 ± 19.28 67.5 ± 12.89 111.0 ± 26.09 Ub_2 128.2 ± 27.06 204.3 ± 49.60 95.2 ± 5.22 91.7 ± 9.76 VT_PS 107.4 ± 7.40 138.2 ± 12.15 70.2 ± 16.40 84.3 ± 22.80 F-test NS * ** ** SED 42.4 16.7 28.5 External bracts Cl_C3 57.3 ± 5.56 42.9 ± 4.49 37.6 ± 8.53 18.2 ± 2.77 Cl_MSP 27.6 ± 0.77 12.8 ± 3.78 21.2 ± 3.39 16.1 ± 2.57 As 45.5 ± 4.93 37.0 ± 4.82 40.8 ± 3.63 42.6 ± 10.25 Cs 34.1 ± 8.87 38.1 ± 6.55 32.1 ± 2.04 24.2 ± 3.38 Je 64.7 ± 12.85 80.5 ± 13.40 54.4 ± 10.96 53.7 ± 16.83 Mz 27.5 ± 2.79 21.7 ± 5.90 48.1 ± 5.17 34.0 ± 8.95 ML_A 31.9 ± 6.81 36.6 ± 1.91 27.4 ± 3.67 17.9 ± 5.71 ML_B 27.5 ± 1.78 27.2 ± 5.04 31.5 ± 10.47 20.9 ± 7.52 Ub_1 80.9 ± 8.72 93.9 ± 10.09 35.8 ± 4.19 38.4 ± 2.52 Ub_2 58.8 ± 16.82 71.4 ±20.49 39.1 ± 6.21 19.1 ± 6.07 VT_PS 57.6 ± 2.45 59.4 ± 4.90 39.2 ± 6.46 36.7 ± 3.85 F-test ** ** NS ** SED 11.5 12.7 10.8 Galieni et al. - Biochemical differences among artichoke genotypes 29 (i.e. receptacle - TPC_Rec, TFC_Rec, ABTS_Rec and DPPH_Rec - and external bracts - TPC_Bra, TFC_Bra, ABTS_Bra and DPPH_Bra), and the eleven artichoke accessions, were summarized by PCA. The results, on the basis of harvest time, are graphically displayed in two correlation bi-plots (Figs. 3A and 3B, respective- ly); in Table 4 are reported the factor loadings, the eigenvalues and the percentage of the explained variance. In early-spring harvesting time (i.e. referring to main capitula data), the first and second principal components explained 90.2% of the total data vari- ability (80.7 and 9.5% for PC1 and PC2, respectively) (Table 4). The variables were grouped into two dis- tinct clusters, separated by PC2: in the upper right quadrant, we found all the chemical data related to the external bracts samples (TPC_Bra, TFC_Bra, ABTS_Bra and DPPH_Bra) while in the bottom right s e c t i o n , t h o s e r e l a t e d t o t h e r e c e p t a c l e o n e s (TPC_Rec, TFC_Rec, ABTS_Rec and DPPH_Rec); all the variables reached high PC1 scores (scores from 0.952 to 0.788 for TPC_Rec and TFC_Rec, respectively) (Table 4). Regarding genotypes, Cl_C3, Ub_2, Je, VT_PS and Ub_1 clustered separately on the right along PC1 and were positively associated with all the investigated variables; conversely, Cl_MSP exhibited the highest negative PC1 score (-1.533) followed by ML_B, Mz, Cs, As and ML_A (Fig. 3A). With respect to the mid-spring harvesting time (i.e. referring to first order capitula data), the eigen- values for PC1 and PC2 were 5.28 and 1.71, respec- tively, thus capturing 87.4% of the total data variabili- ty (Table 4). Again, variables were clearly separated by PC2 while genotypes by PC1 (Fig. 3B). In particular, all the variables reached high PC1 scores with the exception of TFC_Bra, which was mainly correlated with PC2 (scores: 0.328 and 0.886 for PC1 and PC2, respectively; Table 4). Je and Mz showed the higher PC1 scores (1.302 and 1.568, respectively) despite they performed very differently with respect to PC2 (scores: 1.668 and -1.679 for Je and Mz, respective- ly). As a consequence, Je was related to higher TPC, ABTS and DPPH values in the waste fractions (exter- nal bracts) while Mz in the edible parts (receptacle). PCA proved to be a useful tool to summarize the biochemical characteristics of the different investi- Fig. 3 - Two dimensional principal component analysis (PCA) cor- relation bi-plot [main capitula/first harvest time (A) and first order capitula/second harvest time (B)]: symbols show the standardized scores on PC1 (x-axis) and PC2 (y- axis) for the eleven artichoke genotypes (see Table 1 for the list of acronyms); vectors coordinates represent the correlations between standardized variables [total polyphenols content in receptacle and external bracts (TPC_Rec and TPC_Bra, respectively), total flavonoids content in receptacle and external bracts (TFC_Rec and TFC_Bra, respectively), radical scavenging activity obtai- ned from two different assays in the receptacle and external bracts (ABTS_Rec and ABTS_Bra, respectively; DPPH_Rec and DPPH_Bra, respectively)] and PCs. Table 4 - Principal component analysis (PCA): factor loadings, eigenvalues and percentage of the explained variance Variables Main capitula First order capitula PC1 PC2 PC1 PC2 TPC_core 0.952 -0.093 0.941 -0.288 TFC_core 0.788 -0.561 0.853 -0.242 DPPH_core 0.927 -0.286 0.777 -0.477 ABTS_core 0.916 -0.163 0.831 -0.356 TPC_bratee 0.903 0.418 0.926 0.228 TFC_bratee 0.823 0.084 0.328 0.886 DPPH_bratee 0.933 0.220 0.762 0.572 ABTS_bratee 0.930 0.315 0.912 0.226 Eigenvalue 6.455 0.761 5.284 1.711 Explained variance (%) 80.692 9.515 66.056 21.382 Adv. Hort. Sci., 2019 33(1): 23-31 30 gated artichoke genotypes, and clear conclusions could be obtained, confirming the results in terms of single investigated biochemical parameters. In partic- ular, the reference genotype Cl_C3 and the acces- sions Ub_1, Ub_2, Je and VT_PS confirmed higher TPC, TFC and, consequently, antiradical activity in the main capitula, highlighting their important attitude for fresh consumption. This greater head quality was maintained during all the growing season (i.e. as quality traits of the first order capitula) only for Ub_1, Je and VT_PS. Other genotypes, such as As and, principally, Mz, were clearly characterized by higher bioactive compounds in the first order flower heads and by smaller capitula. These accessions could represent a promising potential as germplasm for future breeding programs to select elite cultivars, characterized by: (i) higher and stable quality traits suitable for fresh consumption (i.e. Je); (ii) high con- centrations of biochemical compounds, especially in the waste products, to be used for processing or pharmaceutical applications although further investi- gations on smaller and waste flower heads are need- ed. 4. Conclusions In conclusion, our results confirm that the capitula of globe artichoke could be considered a functional food thanks to its relevant content of bioactive com- pounds accumulated in both receptacle and external bracts. The properties of the external bracts could be usefully exploited for other end-use purposes, although they are still edible fractions (Fratianni et al., 2007; Pandino et al., 2011). A great and apprecia- ble variation among genotypes in terms of chemical composition and nutritional value exists. Such biodi- versity of the accessions of Abruzzo and Marche Regions should be exploited and utilized, taking into account the peculiarity of each genotype (in terms of both yield and quality) as well as the actual end-use which can be reached. Acknowledgements We gratefully acknowledge Maria Assunta Dattoli for her technical assistance in the chemical analysis and Maria Silvia Sebastiani and Alessandro Giardini for their support in data collection and first elabora- tion. This work was grant by RGV/FAO Project. References ALGHAZEER R., EL-SALTANI H., SALEH N.A., AL-NAJJAR A., NAILI M.B., HEBAIL F., EL-DEEB H., 2012 - Antioxidant and antimicrobial activities of Cynara scolymus L. rhi- zomes. - Mod. Appl. Sci., 6: 54-63. CIANCOLINI A., ALIGNAN M., PAGNOTTA M.A., MIQUEL J., VILAREM G., CRINÒ P., 2013 a - Morphological charac- terization, biomass and pharmaceutical compounds in Italian globe artichoke genotypes. - Ind. Crops Prod., 49: 326-333. CIANCOLINI A., FICCADENTI N., REY N.A., SESTILI S., BERTONE A., SACCARDO F., CRINÒ P., PAGNOTTA M.A., 2013 b - Assessment of genetic variability among globe a r t i c h o k e s p r i n g l a n d r a c e s f r o m M a r c h e r e g i o n revealed by molecular and agronomic traits. - Acta Horticulturae, 983: 87-94. CIANCOLINI A., REY N.A., PAGNOTTA M.A., CRINÒ P., 2012 - Characterization of Italian spring globe artichoke germplasm: morphological and molecular profiles. - Euphytica, 186: 433-443. DABBOU S., DABBOU S., FLAMINI G., PEIRETTI P., PANDINO G., HELAL A.N., 2017 - Biochemical characterization and antioxidant activities of the edible part of globe artichoke cultivars grown in Tunisia. - Int. J. Food Prop., 20 (S1): S810-S819. FAO, 2016 - Statistical database. http://www.faostat.org/- FAO, Roma, Italy. FEMENIA A., ROBERTSON A., WALDRON K., SELVENDRAN R., 1998 - Cauliflower (Brassica oleracea L.), globe arti- c h o k e ( C y n a r a s c o l y m u s ) a n d c i c h o r y w i t l o o f (Cichorium intybus) processing by-products as sources of dietary fibre. - J. Sci. Food Agr., 77: 511-518. FICCADENTI N., PICCININI E., CAMPANELLI G., BERTONE A., ANGELINI P., SEBASTIANI M.S., FERRARI V., 2013 - Valutazione della variabilità genetica di popolazioni marchigiane e abruzzesi di carciofo tardivo ai fini della costituzione di varietà innovative da iscrivere al Registro Nazionale delle Varietà. - Acta Italus Hortus, 8: 54-63. FICCADENTI N., REY N., CIANCOLINI A., CRINÒ P., FERRARI V., CAMPANELLI G., MANCINELLI G., LETEO F., CAIONI M., PICCININI E., SESTILI S., SACCARDO F., PAGNOTTA M.A., 2010 - Genetic variability in globe artichoke populations coming from Marche Italian Region. - Proceedings of the 54th Italian Society of Agricultural Genetics Annual Congress, Matera, 27/30 September, 1.32. FRATIANNI F., TUCCI M., DE PALMA M., PEPE R., NAZZARO F., 2007 - Polyphenolic composition in different parts of some cultivars of globe artichoke (Cynara cardunculus L. var. scolymus (L.) Fiori). - Food Chem., 104: 1282- 1286. GOUVEIA S., CASTILHO P.C., 2011 - Antioxidant potential of Artemisia argentea L’Hér alcoholic extract and its rela- tion with the phenolic composition. - Food Res. Int., 44: 1620-1631. Galieni et al. - Biochemical differences among artichoke genotypes 31 GOUVEIA S., CASTILHO P.C., 2012 a - Helichrysum monizii Lowe: Phenolic composition and antioxidant potential. - Phytochem. Analysis, 23: 72-83. GOUVEIA S.C., CASTILHO P.C., 2012 b - Phenolic composi- tion and antioxidant capacity of cultivated artichoke, Madeira cardoon and artichoke-based dietary supple- ments. - Food Res. Int., 48: 712-724. HYKKERUD A.L., ULEBERG E., HANSEN E., VERVOORT M., MØLMANN J., MARTINUSSEN I., 2018 - Seasonal and yearly variation of total polyphenols, total antho- cyanins and ellagic acid in different clones of cloudber- ries (Rubus chamaemorus L.). - J. Appl. Bot. Food Qual., 91: 96-102. KHASAWNEH M., ELWY H.M., FAWZI N.M., HAMZA A.A., C H E V I D E N K A N D Y A . R . , H A S S A N , A . H . , 2 0 1 4 - Antioxidant activity and lipoxygenase inhibitory effect of Caralluma arabica and related polyphenolic con- stituents. - Am. J. Plant Sci., 5: 1623-1631. KLIMOV S.V., BURAKHANOVA E.A., DUBININA I.M., ALIEVA G.P., SAL’NIKOVA E.B., OLENICHENKO N.A., ZAGOSKINA N.V., TRUNOVA T.I., 2008 - Suppression of the source activity affects carbon distribution and frost hardiness of vegetating winter wheat plants. - Russ. J. Plant Physiol., 55: 308-314. LAROSSA M., LLORACH R., ESPIN J.C., TOMAS-BARBERAN F.A., 2002 - Increase of antioxidant activity of tomato juice upon functionalisation with vegetable byproduct extracts. - LWT Food Science and Technology, 35(6): 532-542. LATTANZIO V., CARDINALI A., DI VENERE D., LINSALATA V., PALMIERI S., 1994 - Browing phenomena in a stored artichoke (Cynara scolymus L.) heads: enzymatic or chemical reaction? - Food Chem., 50: 1-7. LATTANZIO V., KROON P.A., LINSALATA V., CARDINALI A., 2009 - Globe artichoke: a functional food and source of nutraceutical ingredients. - J. Funct. Foods, 1: 131-144. LOMBARDO S., PANDINO G., MAUROMICALE G., 2013 - Total polyphenol content and antioxidant activity among clones of two Sicilian globe artichoke landraces. - Acta Horticulturae, 983: 95-101. LOMBARDO S., PANDINO G., MAUROMICALE G., 2017 - Minerals profile of two globe artichoke cultivars as affected by NPK fertilizer regimes. - Food Res. Int., 100: 95-99. LOMBARDO S., PANDINO G., MAUROMICALE G., KNÖDLER M., CARLE R., SCHIEBER A., 2010 - Influence of geno- type, harvest time and plant part on polyphenolic com- position of globe artichoke [Cynara cardunculus L. var. scolymus (L.) Fiori]. - Food Chem., 119: 1175-1181. MARQUES P., MARTO J., GONÇALVES L.M., PACHECO R., FITAS M., PINTO P., SERRALHEIRO M.L.M., RIBEIRO H., 2017 - Cynara scolymus L.: A promising Mediterranean extract for topical anti-aging prevention. - Ind. Crop. Prod., 109: 699-706. MAUROMICALE G., IERNA A., 2000 - Panorama varietale e miglioramento genetico del carciofo. - L’Informatore Agrario, 56: 39-45. MEGÍAS M.D., HERNÁNDEZ F., MADRID J., MARTÍNEZ- TERUEL A., 2002 - Feeding value, in vitro digestibility and in vitro gas production of different by-products for ruminant nutrition. - J. Sci. Food Agr., 82: 567-572. PANDINO G., LOMBARDO S., MAURO R.P., MAUROMICALE G., 2012 a - Variation in polyphenol profile and head morphology among clones of globe artichoke selected from a landrace. - Sci. Hortic., 138: 259-265. PANDINO G., LOMBARDO S., MAUROMICALE G., 2013 a - Globe artichoke leaves and floral stems as a source of bioactive compounds. - Ind. Crop. Prod., 44: 44-49. P A N D I N O G . , L O M B A R D O S . , M A U R O M I C A L E G . , WILLIAMSON G., 2011 - Profile of polyphenols and phe- nolic acids in bracts and receptacles of globe artichoke (Cynara cardunculus var. scolymus) germplasm. - J. Food Compos. Anal., 24: 148-153. P A N D I N O G . , L O M B A R D O S . , M A U R O M I C A L E G . , WILLIAMSON G., 2012 b - Characterization of phenolic acids and flavonoids in leaves, stems, bracts and edible parts of globe artichokes. - Acta Horticulturae, 942: 413-417. PANDINO G., LOMBARDO S., MONACO A.L., MAUROMI- CALE G., 2013 b - Choice of time of harvest influences the polyphenol profile of globe artichoke. - J. Funct. Foods, 5: 1822-1828. PETROPOULOS S.A., PEREIRA C., NTATSI G., DANALATOS N., BARROS L., FERREIRA I.C., 2017 - Nutritional value and chemical composition of Greek artichoke geno- types. - Food Chem., 267: 296-302. R CORE TEAM, 2017 - R: A language and environment for statistical computing. - R Foundation for Statistical Computing, Vienna, Austria. RE R., PELLEGRINI N., PROTEGGENTE A., PANNALA A., YANG M., RICE-EVANS C., 1999 - Antioxidant activity applying an improved ABTS radical cation decoloriza- tion assay. - Free Radical Bio. Med., 26: 1231-1237. ROUPHAEL Y., COLLA G., GRAZIANI G., RITIENI A., CAR- DARELLI M., DE PASCALE S., 2017 - Phenolic composi- tion, antioxidant activity and mineral profile in two seed- propagated artichoke cultivars as affected by microbial inoculants and planting time. - Food Chem., 234: 10-19. SCHÜTZ K., KAMMERER D., CARLE R., SCHIEBER A., 2004 - Identification and quantification of caffeoylquinic acids and flavonoids from artichoke (Cynara scolymus L.) heads, juice, and pomace by HPLC-DAD-ESI/MS n. - J. Agr. Food Chem., 52: 4090-4096. SIHEM D., SAMIA D., GAETANO P., SARA L., GIOVANNI M., HASSIBA C., LAURA G., NOUREDDINE H.A., 2015 - In vitro antioxidant activities and phenolic content in crop residues of Tunisian globe artichoke. - Sci. Hortic., 190: 128-136. SOUMAYA K., CHAOUACHI F., KSOURI R., EL GAZZAH M., 2013 - Polyphenolic composition in different organs of Tunisia populations of Cynara cardunculus. L. and their antioxidant activity. - J. Food Nutr. Res., 1: 1-6.