Elution-extrusion and back-extrusion counter-current chromatography using three-phase solvent system for separation of organic dye mixture

Recent trends in multidimensional countercurrent chromatography

Countercurrent chromatography (CCC) is a potent separation approach known for its remarkable efficiency and capacity in preparation. It's applied as a substitute or combined with different chromatographic techniques, resulting in its rebranding as multidimensional CCC (MDCCC). Numerous essential mixtures from natural products contain hundreds or thousands of distinct components of importance. These mix types are too complicated to separate in any reasonable time using a single CCC dimension. However, if a multidimensional technique is utilized, where a complex mixture is separated by an initial dimension, smaller fractions of that separation are gathered. Each fraction is studied individually; complex mixes can be resolved relatively quickly. Thus, several MDCCC separation features have been studied to demonstrate their advantages, limitations, and prospective capacity to separate exceedingly complex mixtures. In this review, MDCCC aspects, including principles, multiple columns system, multilayer coil J-type, on-line monitoring system, and applications, have been thoroughly_explored.

A novel strategy by combining foam fractionation with high-speed countercurrent chromatography for the rapid and efficient isolation of antioxidants and cytostatics from Camellia oleifera cake

Camellia oleifera cake is a by-product, which is rich in functional chemical components. However, it is typically used as animal feed with no commercial value. The purpose of this study was to isolate and identify compounds from Camellia oleifera cake using a combination of foam fractionation and high-speed countercurrent chromatography (HSCCC) and to investigate their biological activities. Foam fractionation with enhanced drainage through a hollow regular decahedron (HRD) was first established for simultaneously enriching flavonoid glycosides and saponins for further separation of target compounds. Under suitable operating conditions, the introduction of HRD resulted in a threefold increase in enrichment ratio with no negative effect on recovery. A novel elution-extrusion countercurrent chromatography (EECCC) coupled with the consecutive injection mode was established for the successful simultaneous isolation of flavonoid glycosides and saponins. As a result, 38.7 mg of kaemferol-3-O-[2-O-D-glucopyranosyl-6-O-α-L-rhamnopyranosyl]-β-D-glucopyranoside (purity of 98.17%, FI), 70.8 mg of kaemferol-3-O-[2-O-β-D-xylopyranosyl-6-O-α-L-rhamnopyranosyl]-β-D-glucopyranoside (purity of 97.52%, FII), and 560 mg of an oleanane-type saponin (purity of 92.32%, FIII) were separated from the sample (900 mg). The present study clearly showed that FI and II were natural antioxidants (IC50 < 35 μg/mL) without hemolytic effect. FIII displayed the effect of inhibiting Hela cell proliferation (IC50 < 30 μg/mL). Further erythrocyte experiments showed that this correlated with the extremely strong hemolytic effect of FIII. Overall, this study offers a potential strategy for efficient and green isolation of natural products, and is beneficial to further expanding the application of by-products (Camellia oleifera cake) in food, cosmetics, and pharmacy.

Fermentation of Agaricus bisporus for antioxidant activity: response surface optimization, chemical components, and mechanism

Agaricus bisporus is one of the most widely cultivated edible mushrooms in the world. The chemical components of A. bisporus have a wide range of biological activities. In order to deeply understand the antioxidant properties of A. bisporus, this study conducted an investigation on the components of A. bisporus fermentation. Through the single factor experiment and response surface optimization, it was found that when the C/N ratio was 45:1, the inoculum concentration was 10%, and the fermentation time was 7 d, the n-butanol extract of the fermentation product had the strongest scavenging capacity for free radical generated through 2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulphonic acid (ABTS·⁺). The concentration for 50% of the maximal effect (EC₅₀) was 0.33 ± 0.01 mg/mL. Moreover, in order to identify the two main components, the elution-extrusion counter-current chromatography (EECCC) was employed for separation, where 5,5'-oxy-dimethyl-bis(2-furfuraldehyde) and 5-(butoxymethyl) furfural were obtained. The antioxidant activity of 5,5'-oxy-dimethyl-bis(2-furfuraldehyde) (EC₅₀ = 0.26 ± 0.01 mg/mL) was superior to that of 5-butylmethyl furfural (EC₅₀ = 1.52 ± 0.02 mg/mL), indicating that 5,5'-oxy-dimethyl-bis(2-furfuraldehyde) was the main antioxidant in the fermentation products. The thermodynamic parameters and frontier molecular orbitals of 5,5'-oxy-dimethyl-bis (2-furanaldehyde) was evaluated by density functional theory (DFT). The result indicated 5,5'-oxy-dimethyl-bis(2-furanaldehyde) scavenged free radicals in polar media through single electron transfer followed by proton transfer (SET-PT).

Comprehensive separation of a wide variety of compounds from olive leaves by counter-current chromatography with three-phase solvent system

The three-phase solvent system counter-current chromatography has been of great research interest, because it can separate compounds with a wide range of polarity. The solvent system of n-hexane/methyl tert-butyl ether/acetonitrile/water (5:5:7:5, v/v) was used for counter-current chromatographic comprehensive separation of olive leaves. The study adopted the normal elution mode. The middle phase and the lower phase (at a volume ratio of 7:3) were pumped into the column simultaneously, followed by eluting with the upper, middle and lower phases in sequence. The retention rate of the stationary phase measured by the experiment was 73.5%. The upper phase was used to eluted the nonpolar compounds, then the mobile phase was switched to the middle phase to elute the moderately hydrophobic compounds, finally, the polar compounds were eluted by the lower phase remaining in the chromatographic column. This method successfully separated eight compounds in one step within 270 minutes and five compounds were identified. The logP values of these five compounds were 7.44, 7.86, 4.16, -0.11, 0.96, respectively, covering a wide range of polarities. The present study demonstrated that the three-phase solvent has a strong extraction capacity for ingredients from extremely hydrophilic compounds to extremely hydrophobic compounds. This article is protected by copyright. All rights reserved.

Characterization, Large-Scale HSCCC Separation and Neuroprotective Effects of Polyphenols from Moringa oleifera Leaves

Moringa oleifera leaves have been widely used for the treatment of inflammation, diabetes, high blood pressure, and other diseases, due to being rich in polyphenols. The main objective of this work was to largely separate the main polyphenols from Moringa oleifera leaves using the technique of high-speed counter-current chromatography (HSCCC). The phenolic composition in Moringa oleifera leaves was first analyzed qualitatively and quantitatively by UPLC-Q-Exactive Orbitrap/MS and UPLC-QqQ/MS, respectively, indicating that quercetin and kaempferol derivatives, phenolic acid and apigenin are the main polyphenols in Moringa oleifera leaves, with quercetin and kaempferol derivatives predominating. Furthermore, the conditions of HSCCC for large-scale separation of polyphenols from Moringa oleifera leaves were optimized, which included the selection of the solvent system, flow rate and the sample load. Only by one-step HSCCC separation (within 120 min) under the optimized conditions, six quercetin and kaempferol derivatives, a phenolic acid and an apigenin could be individually isolated at a large scale (yield from 10% to 98%), each of which possessed high purity. Finally, the isolated polyphenols and phenolic extract from Moringa oleifera leaves (MLPE) were verified to have strong neuroprotective activities against H₂O₂-induced oxidative stress in PC-12 cells, suggesting that these compounds would contribute to the main beneficial effects of Moringa oleifera leaves.

Role of three-phase solvent system in the counter-current chromatography

In counter-current chromatography, the separation efficiency greatly depends on the partitioning ability of the separated substance between the stationary phase and the mobile phase. Partitioning ability is mainly represented by the parameter partition coefficient which is one of the important parameters to evaluate the separation effect of counter-current chromatography. The scope of the partition coefficient value mainly depends on the solvent system. A suitable solvent system election is, therefore, a critical role in the separation of counter-current chromatography. The existing solvent systems that are widely used are mainly two-phase solvent systems. It is difficult to decide on an appropriate solvent system for the separation of compounds with a wide polarity range, which promotes the development of the three-phase solvent system in counter-current chromatography. This review mainly described the origin, development history of three-phase solvent system, summarized the volume ratios and volume fractions of the upper, middle, and lower phases of nearly 50 three-phase solvent systems, their advantages, and disadvantages in counter-current chromatography. In addition, the challenges and future perspectives on three-phase solvent systems in counter-current chromatography also are discussed in this review.