An efficient strategy based on liquid‐liquid extraction and pH‐zone‐refining counter‐current chromatography for selective enrichment, separation, and purification of alkaloids and organic Acids from natural products

Abstract

This study presents an efficient strategy based on liquid‐liquid extraction and pH‐zone‐refining counter‐current chromatography for selective enrichment, separation, and purification of alkaloids and organic acids from natural products. First, an acid or base modified two‐phase solvent system with maximum or minimum partition coefficient was developed for the liquid‐liquid extraction of the crude extract. As a result, alkaloids or organic acids could be selectively enriched in the upper or lower phase. Then pH‐zone‐refining counter‐current chromatography was employed to separate and purify the selectively enriched alkaloids or organic acids efficiently. The selective enrichment and separation of five bufadienolide from toad venom of Bufo marinus was used as an example to show the advantage of this strategy. As a result, 759 mg of selectively enriched bufadienolide was obtained from 2 g of crude extract and the total content of five targets was increased from 14.64 to 83%. A total of 31 mg of marinobufagin‐3‐adipoyl‐l‐arginine, 42 mg of telocinobufagin‐3‐pimeloyl‐l‐arginine, 51 mg of telocinobufagin‐3‐suberoyl‐l‐arginine, 132 mg of marinobufagin‐3‐suberoyl‐l‐arginine, and 57 mg of bufalin‐3‐suberoyl‐l‐arginine were all simultaneously separated from 500 mg of selectively enriched sample, with the purity of 92.4, 97.5, 90.3, 92.1, and 92.8%, respectively.

Caesalpinia palmeri: First Report on the Phenolic Compounds Profile, Antioxidant and Cytotoxicity Effect

“…Also, their use is recurrent due to the ease, simplicity and accessibility of the method. [24] Because of the markedly higher concentration of phenolic compounds in the flower extract, it was selected to characterize its profile in more detail. In this regard, the flower extract was subjected to a liquid-liquid partition process using solvents of differ-ent polarity, which allowed to obtain of the residual fraction, ethyl acetate fraction, and hexane fraction.…”

“…Liquid‐liquid partitioning process is a method that allows separate compounds or groups of compounds according to their relative solubility in two immiscible liquids. Also, their use is recurrent due to the ease, simplicity and accessibility of the method [24] …”

Factors that influence the extraction methods of terpenes from natural sources

“…Like the conventional liquid-liquid extraction method, terpenoids with functional groups that present acid-base balances (carboxyl and amino) can be recovered, by varying the pH in the aqueous phase, and the terpenoid remains in the phase where it is more soluble. Additionally, this method allows the use of multiple solvents for the extraction process in one run, and these can be recirculated to make it a continuous and more efficient process (Spórna-Kucab et al 2020;Yu et al 2020). This technique has been used at the end of the purification process, performing polishing, and there are some optimized extraction systems for the recovery of terpenes/oids (Table 4) (Friesen et al 2015;Liu et al 2014Liu et al , 2015Marques et al 2018;Spórna-Kucab et al 2020;Yu et al 2020).…”

Separation and purification of quinolyridine alkaloids from seeds of Thermopsis lanceolata R. Br. by conventional and pH‐zone‐refining counter‐current chromatography

“…Compared with traditional CCC, PZR-CCC shows around 10-fold increases in sample loading, great peak concentration, and minor impurity enrichment. PZRCCC is successfully applied for separating ionic compounds such as organic acids and alkaloids [16,17].…”