Chemical Composition, Antioxidant Potential and Enzymes Inhibitory Properties of Globe Artichoke By‐Products

Abstract

In this study, chemical composition and in vitro biological activities of artichoke by‐products (leaves, floral stems and bracts) issued from two Tunisian varieties were evaluated. Analysis was performed by means of high‐performance liquid chromatography with diode array detection coupled to electrospray ionization mass spectrometric (LC/DAD/ESI‐MS). Total phenolic (TPC) and flavonoid (TFC) contents as well as the antioxidant activity conducted by three complementary methods, DPPH, ABTS and FRAP tests, were performed for each sample. Enzyme inhibitory effects against acetylcholinesterase, butyrylcholinesterase and α‐amylase were also studied. Results showed that TPC and TFC varied according to variety as well as the plant part. Bracts presented the highest TPC values (10–15 mg GAE/g DW), while leaves were distinguished by the highest TFC values (52–58 mg EQ/g DW). In vitro assays showed that Violet d'Hyères bracts and Blanc d'Oran leaves present the most antioxidant activities (30.040 and 20.428 mgET/gDW, respectively, by the DPPH method). Leaves demonstrated the highest acetylcholinesterase and butyrylcholinesterase inhibitory effects. Moreover, all organs displayed a noticeable inhibition towards α‐amylase. LC/DAD/MS analysis revealed that artichoke by‐products are a potential source of biopharmaceuticals such as luteolin derivatives from leaves and mono/dicaffeoylquinic acids in the other parts. This research demonstrates that globe artichoke by‐products, unexploited in our country, are a promising source of natural health promoting compounds with potential applications in the food and pharmaceutical industries.

Antioxidant and Anti-Inflammatory Effects of Extracts from Pulsed Electric Field-Treated Artichoke By-Products in Lipopolysaccharide-Stimulated Human THP-1 Macrophages

“…The resulting chromatograms, depicted in Figure 1 , showed that the two extracts presented similar chromatogram profiles and that PEF pre-treatment of artichoke stems remarkably increased the peak areas of the major phenolic compounds present in the AEs, corresponding to chlorogenic acid (peak 3), followed by naringin (peak 7), rutin (peak 8) catechin (peak 2), epicatechin (peak 4), sinapic acid (peak 6), phlorizin (peak 9), cynarine (peak 5) and gallic acid (peak 1). The obtained results are consistent with previous findings by other authors [ 18 , 23 ]. They reported that, among phenolic compounds, caffeoylquinic acids were the most abundant hydroxycinnamic acids in artichoke residues, with chlorogenic acid being present to a greater extent.…”

“…For instance, the TPCs of extracts from artichoke sprouts and stalks from different Italian locations detected by Ferioli and D’Antuono were in the range of 8.9–34.9 mg GAE/gDW [ 50 ]. Similarly, Rejeb et al found the TPCs of extracts from artichoke floral stems to be equal to 10.689 ± 0.324 mg GAE/gDW [ 23 ]. Moreover, the composition, in terms of the most abundant phenolic compounds, of the extracts from untreated and PEF-treated artichoke stems subject to optimal processing conditions was assessed via HPLC–PDA analysis.…”

“…Specifically, among the hydroxycinnamic acids, 5-O-caffeoylquinic acid (chlorogenic acid), 1,5-O- and 3,5-O-dicaffeoylquinic acids are the most abundant, while the main flavonoids present in the artichoke residues are apigenin and luteolin glycosides [ 13 , 14 ]. Interestingly, it has been reported that, due to the phenolic content, artichoke extracts not only possess radical scavenging potential, antioxidant, anti-inflammatory, antibiotic and anti-carcinogenic properties [ 15 , 16 , 17 , 18 , 19 ], but also exhibit in vitro inhibitory potential against the main enzymes involved in the onset of metabolic syndromes [ 20 , 21 , 22 , 23 , 24 ].…”

Neuroprotective Effects of Agri-Food By-Products Rich in Phenolic Compounds

“…Then, other reports of AChE inhibitory activity where the catechin content was high enough could be also explained [ 67 , 78 , 83 ]. Ben Rejeb et al (2020) stated that extracts from artichoke by-products (leaves, bracts and stems) inhibited AChE and BChE activity, and they related this to the presence of flavonoids in a positive and significant way [ 93 ]. In fact, they highlighted luteolin and its derivatives as the main contributing factor, and reported that flavonoids such as quercetin were able to block the entrance to the active site of AChE and BChE enzymes.…”

“… Main mechanisms through which plant extracts and their phenolic compounds exert their neuroprotective effects, as well as key cell processes involved. Finally, several references in which this information is demonstrated [ 30 , 34 , 41 , 48 , 57 , 58 , 75 , 79 , 80 , 81 , 85 , 86 , 87 , 88 , 89 , 92 , 93 , 95 , 102 , 108 , 110 , 115 , 123 , 130 , 131 ]. …”