Separation of betacyanins from flowers of Amaranthus cruentus L. in a polar solvent system by high‐speed counter‐current chromatography

Abstract

Betacyanin extract of Amaranthus cruentus L. flowers was fractionated by semi‐preparative high‐speed counter‐current chromatography in a highly polar solvent system: propan‐1‐ol/acetonitrile/(NH4)2SO4satd. soln/H2O (1.0:0.5:1.2:1.0, v/v/v/v) in tail‐to‐head mode with 76% retention of the stationary phase. The crude extract as well as the fractions containing betacyanins were analyzed by liquid chromatography with tandem mass spectrometry as well as by high‐resolution ion‐trap time‐of‐flight mass spectrometry detection technique for the molecular formulae and multi‐step fragmentation pattern elucidation. Four betacyanins; namely, amaranthin, betanin, 6′‐O‐formyl‐amaranthin, and 6′‐O‐malonyl‐amaranthin as well as their diastereomeric forms differing in the configuration of the C‐15 carbon atom were identified in the fractions. Amaranthin was the dominant pigment in the extract and was additionally analyzed by nuclear magnetic resonance correlation techniques after the counter‐current chromatographic and high‐performance liquid chromatographic isolation. Betacyanins were highly enriched during a single high‐speed counter‐current chromatographic step; therefore, the tentative identification of new compounds for the whole Amaranthaceae family, 6′‐O‐formyl‐amaranthin and 6′‐O‐malonyl‐amaranthin was possible. Different elution profiles of the pigments observed in the counter‐current chromatographic system in comparison to high‐performance liquid chromatography system confirm a complementarity of both the techniques especially in the separation of diastereomeric pairs of betacyanins.

Salinity differently affects antioxidant content and amino acid profile in two cultivars of Amaranthus cruentus differing in salinity tolerance

“…44 Although the spectrophotometric quantification did not discriminate between the two classes of compounds, it is commonly considered that their occurrences in the plant kingdom are mutually exclusive and that A. cruentus accumulate betalain such as amaranthine which has numerous chemopreventive actions in human health. 45 Beside the AOAM fraction, the antioxidant capacity of the AOAD lipophilic fraction also increased in NaCl-treated plants. Tocopherols are important lipophilic bioactive molecules protecting lipids from oxidation.…”

Comprehensive separation of iridoid glycosides and triterpenoid saponins from Dipsacus asper with salt‐containing solvent by high‐speed countercurrent chromatography coupled with recycling mode

“…According to previous reports about HSCCC solvent systems for polar compounds, inorganic salt can be added to adjust the T A B L E 1 K D of compounds 1-3 obtained from sample II in different solvent systems Peak No. hydrophilia of the solvent system to promote the partition of polar compounds in the organic phase [18,19]. Thus, several inorganic salts including ammonium acetate, ammonium sulfate, and potassium sulfate with different concentrations and volume ratios were added in solvent system of n-butanol/acetonitrile/water (3:1:4, v/v/v) to partially substitute water and accordingly alter the K D values of compounds 1-3 (Table 1).…”

Full use of the liquid nature of the stationary phase: The development of elution‐extrusion counter current chromatography

“…Thirdly, it uses less solvent for separation of per‐unit solute makes the separation relatively economical and environmentally friendly [3]. For all the above advantages, CCC has been widely used in separation field, and especially in the separation of natural products [4‐7]. However, the use of CCC is limited in the separation of compounds covering a broad polar range.…”