Separation of some chiral flavanones by micellar electrokinetic chromatography

Abstract

Micellar electrokinetic chromatography (MEKC) was applied for enantioseparation of selected flavanones, including naringin, hesperidin, neohesperidin, naringenin, hesperetin, pinostrobin, isosakuranetin, eriodictyol, and homoeriodictyol. gamma-Cyclodextrin (gamma-CD) and sodium cholate (SCh) were used as chiral modifiers inducing enantioselectivity to the background electrolyte. From among many investigated selectors only these two appeared to possess the best enantioselective properties in respect to studied flavanones. The mechanisms of their action are a little different; SCh used above critical micelle point concentration forms chiral micelles itself while gamma-CD is deprived of this property and requires addition of surfactants as, e.g., sodium dodecyl sulfate. It was found that SCh enables separation of flavanone glycosides diastereomers while separation of enantiomers of flavanone aglycones may be achieved with gamma-CD. Consideration of structural relation led to the suggestion that interaction of sugar moiety of glycosides with SCh micelles give rise to chiral recognition. MEKC appeared to be a suitable and efficient analytical tool to follow enantiomeric composition of flavanones.

Carboxymethylated cyclosophoraose as a novel chiral additive for the stereoisomeric separation of some flavonoids by capillary electrophoresis

“…Interconversion profiles featuring characteristic plateau formation of the elution patterns were observed at high pH. 9 We also observed the plateau for naringin (Fig. 3E).…”

“…The importance of stereospecific disposition of racemic flavanones has been recognized and reported over the last 20 years. 5 In capillary electrophoresis, stereoisomeric forms of flavonoids could be generally discriminated in the presence of a chiral environment through molecular interactions due to the stereospecific complexation in the hydrophobic parts of polysaccharide, 6 cyclodextrin, cyclodextrin derivatives, [7][8][9][10][11][12][13] and microbial oligosaccharides. [14][15][16][17][18][19] Almost all the flavanones have one chiral carbon atom in the 2-position except for a subclass of flavanones named the 3-hydroxyflavanones or dihydroflavonols that have two chiral carbon atoms in the 2-and 3-positions (Fig.…”

Methods of analysis and separation of chiral flavonoids

“…Separation of some chiral flavanones by micellar electrokinetic chromatography has also been accomplished [63]. ␥-cyclodextrin and sodium cholate were used as chiral mobile phase additives.…”

“…Most of these investigations report the quantification of a variety of flavanones in citrus fruit juices and herbs [12,25,[59][60][61][62], or report the separation of flavanones on different stationary phases [63][64][65][66][67][68][69][70][71][72]. There is a paucity of investigations detailing the importance of stereospecific pharmacokinetics and pharmacodynamics of chiral flavanones.…”

Separation of the enantiomers of naringenin and eriodictyol by amylosebased chiral reversed-phase high-performance liquid chromatography

“…It is well known that interactions with enzymes are often stereospecific, so enantiomers should have different behaviors in pharmacological action and metabolic process, but due to the lack of readily available pure flavanone enantiomers, most bioactivity studies were carried out using a racemic mixture. For the separation of enantiomers of compounds 1 and 2, a couple of methods have been previously reported, such as capillary electrophoresis (13), micellar electrokinetic chromatography (14), and high performance liquid chromatography (HPLC) under normal-phase conditions (15). With respect to normal phase and polar organic mobile phase, the reversed-phase mode is particularly advantageous in the direct analysis of biological matrices without a batch sample preparation step and in coupling with mass spectrometry.…”