Seasonal variation of bioactive properties and phenolic composition of Cynara cardunculus var. altilis

Abstract

Cynara cardunculus L. (cardoon) has several health benefits mainly attributed to its abundance in polyphenols. In this study, cardoon heads (capitula) were harvested in Greece during the flowering stage, and the hydroethanolic extracts were assessed in terms of phenolic compounds composition and antioxidant, cytotoxic, anti-inflammatory, and antimicrobial activities. The phenolic profile was evaluated by HPLC-DAD-ESI/MS to better understand the seasonal changes in the individual compound levels and how these changes correlate with bioactive properties. The main phenolic compounds identified were caffeoylquinic and dicaffeoylquinic acid derivatives. Immature heads (Car A: principal growth stage (PGS) 5) had the highest phenolic content (34.3 mg/ g) and cytotoxic (GI 50 of 69-268 µg/mL) and anti-inflammatory (IC 50 of 183 µg/mL) activities. Sample Car D (PGS 6/7) revealed the highest antioxidant (IC 50 of 23-227 µg/mL) and antifungal (MIC of 0.26-0.51 mg/mL) potential. Regarding the antibacterial activity, Car E (PGS 7) revealed the best results (MIC of 0.59-1.18 mg/ mL). This study suggests that the maturity stage of the plant influences the phenolic composition and bioactivity.

Chemical Composition of Cynara Cardunculus L. var. altilis Heads: The Impact of Harvesting Time

“…Sample Car B was the only sample with a PUFA/SFA value higher than 0.45 and an n-6/n-3 ratio value lower than 4.0, both characteristics being associated with good nutritional properties. This evidence agrees with the popular medicine, since in the Mediterranean cousin cardoon heads are used when immature [19,42,43]. With the results obtained in this study, we corroborate the consumption of immature cardoon heads, preferably harvested in the beginning of May, based on the conditions of the growing location.…”

“…In a previous study, we studied the bioactive properties of cardoon heads also analyzed in the present work and despite the antioxidant capacity associated with tocopherols, the anticipation that the sample Car B with the highest tocopherols content would show the greater antioxidant activity was not verified. This fact suggests that other classes of compounds, such as phenolic compounds, could be also related to the demonstrated antioxidant potential [19], while Kukić et al [44] suggested that β-sitosterol possessed a strong antioxidant capacity in extracts obtained from cardoon bracts. Despite that, the highest content of α-tocopherol in this sample could be associated with the highest content in PUFAs (see Table 2) highlighting the protective effects of tocopherols against lipid peroxidation [45,46].…”

“…Similarly, in sample C sucrose, fructose and raffinose were detected in the highest amounts, whereas in the following stages (samples D-F) total sugars content was significantly reduced consisting mainly of trehalose. Considering that the tested samples were collected under environmental conditions [19] could justify the observed differences in sugar composition between the various maturity stages. According to Petropoulos et al [34] who studied the influence of the genotype on different parameters of cardoon heads, significant differences between the genotypes tested were also suggested.…”

“…Heads were collected from 15 individual plants (n = 15) at the beginning of the flower's development, in full maturity, and in seed ripening stages. The climate conditions during the growing period and the procedure used for the collection and treatment of plant material were described by Mandim et al [19]. Briefly, Car A corresponds to principal growth stage (PGS) 5 (harvest: 26 April 2018), Car B corresponds to PGS 5/6 (harvest: 10 May 2018), Car C corresponds to PGS 6 (harvest: 24 May 2018), Car D corresponds to PGS 6/7 (harvest: 04 July 2018), and finally the samples Car E and Car F correspond to PGS 7 and PGS8, respectively (harvest: 09 August 2018 and 29 August 2018, respectively) [19,26].…”

Chemical Composition of Cynara cardunculus L. var. altilis Bracts Cultivated in Central Greece: The Impact of Harvesting Time

“…Moreover, although the sample C8 had a higher content in tocopherols and was more efficient to inhibit oxidative hemolysis (OxHLIA), the same was not true for the inhibition of lipid peroxidation (thiobarbituric acid reactive substances; TBARS), where sample C1 revealed a superior antioxidant potential [32]. The same observation was also made in samples of cardoon heads [40], suggesting that other classes of compounds are involved in the antioxidant capacity demonstrated by the analyzed samples. Moreover, it is very common in natural matrices to exhibit variable effectiveness in various antioxidant activity assays, since different compounds and mechanisms are involved in different assays [41,42].…”