Quantitative Determination of Phenolic Compounds in Artichoke-Based Dietary Supplements and Pharmaceuticals by High-Performance Liquid Chromatography

Abstract

Dietary supplements are among the most rapidly growing products in the food and personal care market with an estimated worldwide volume exceeding $60 billion. The main problem associated with dietary supplements is their legal classification. Being neither food nor medicine, they often inhabit a gray area between the two, which makes legal regulatory extremely difficult. Thus, a coexistence of products processed from the same botanical source on the same market as dietary supplement or pharmaceutical is possible. In the present study, various artichoke-based dietary supplements were investigated for their phenolic profile and compared to artichoke phytopharmaceuticals. Quantification of individual hydroxycinnamic acids and flavonoids was carried out by external calibration. For the first time, determination of several apigenin derivatives was included. Chlorogenic acid represented the major constituent in all samples investigated with the exception of juice derived from fresh flower heads, which exhibited a higher cynarin content. Furthermore, a distinction between products made from artichoke leaves or flower heads was possible. The results obtained revealed great diversity of pharmaceuticals and dietary supplements, highlighting the need of standardized quality requirements.

Comparative Chemomapping of Phytoconstituents from Different Extracts of Globe Artichoke - Cynara Scolymus L.

“…Our study was meant to identify all possible phytoconstituents with the used experimental setup, and as a consequence 49 and 51 molecules were described in the aqueous and hydro-alcoholic artichoke extracts, respectively. Some of the newly identified compounds were confirmed by standards, while other compounds have already been reported by others [15][16][17][18][19][20][21][22][23][24][25][26].…”

Infusions of artichoke and milk thistle represent a good source of phenolic acids and flavonoids

“…Despite the many articles reporting the phenolic composition of artichoke hydroalcoholic extracts, 13,15,16,[31][32][33][34][35][36][37][38][39][40] the present work characterizes the phenolic composition in infusions. Moreover, infusion is the most common form to consume this plant and, to our knowledge, this is also the first report presenting results for the whole plant material and not seeds.…”

“…The assignments of the different caffeoylquinic, feruloylquinic and p-coumaroylquinic acid isomers were made using the recommended IUPAC numbering system and also the hierarchical keys previously developed by Clifford et al 29,30 Compound 1 ([M -H] − at m/z 353) was identified as 3-Ocaffeoylquinic acid, yielding the base peak at m/z 191 ([quinic acid-H] − ) and the ion at m/z 179 ([caffeic acid-H] − ) with an intensity >63% base peak, characteristic of 3-acylchlorogenic acids as reported by Clifford et al 29,30 Monocaffeoylquinic acids have been largely reported by many authors in different parts of artichoke, such as heads and leaves, 13,15,[31][32][33][34][35][36][37][38] hearts, 16 wastes such as bracts, receptacles and stems from the fruit, 39 juices and pomace, 15,32 and in dietary supplements. 15,37,40 Compound 22 present in milk thistle and artichoke was identified as 3,5-O-dicaffeoylquinic acid based on its fragmentation pattern being similar to that reported by Clifford et al 30 The MS 2 base peak was at m/z 191, but also presented a very high relative abundance at m/z 353, produced by the loss of one of the caffeoyl moieties [M − H-caffeoyl] − , whose subsequent fragmentation yielded the same fragments as 5-Ocaffeoylquinic acid at m/z 191, 179 and 135. Compound 10 (artichoke) was identified as 1,3-O-dicaffeoylquinic acid (cynarin) according to its MS 2 fragmentation and elution characteristics, being the most hydrophilic dicaffeoylquinic acid.…”

“…41 Dicaffeoylquinic acids have been extensively reported in Table 2 Retention time (Rt), wavelengths of maximum absorption in the visible region (λ max ), mass spectral data, identification and quantification of phenolic compounds in hydromethanolic extract and infusion of milk thistle (mean ± SD) a hydroalcoholic extracts obtained from different parts of artichoke, as mentioned above. 13,15,16,[31][32][33][34][35][36][38][39][40] Four signals in artichoke (compounds 4, 9, 11 and 13) showed a pseudomolecular ion ([M − H] − ) at m/z 337 (Tables 1 and 2). These compounds were assigned as the 3-acyl, 4-acyl and 5-acyl isomers of p-coumaroylquinic acid based on their HPLC retention and MS 2 fragmentation characteristics, as previously reported by Clifford et al 29,42 Thus, compound 4 (artichoke) was tentatively identified as 3-p-coumaroylquinic acid, yielding the base peak at m/z 163 ([coumaric acid-H] − ).…”

“…15,37,40 Compound 20 presented a pseudomolecular ion [M − H] − at m/z 461 releasing a fragment ion at m/z 285 ([M − 176] − , loss of a glucuronyl moiety); although the position of the glycosyl moiety could not be established it was assigned to luteolin 7-O-glucuronide, owing to the identification of that compound in leaves, heads, hearts, juices, pomaces and dietary supplements of artichoke, mostly obtained after hydroalcoholic extraction. 13,15,16,32,33,[35][36][37]39,40 In accordance with their UV and mass spectra characteristics, different apigenin derivatives were also detected in the analysed samples. Compounds 24, 27 (artichoke) and 26 (artichoke and milk thistle) showed pseudomolecular and fragment ions coherent with deoxyhexosyl-hexoside, hexoside and glucuronide derivatives of apigenin, respectively.…”