Preparation of a novel chiral stationary phase containing rhizobial cyclic β-(1→2) glucans for the chiral separation of some flavonoids

Cys-immobilized CSP for HPLC were prepared by a three-step procedure. First, Cys were isolated from Rhizobium leguminosarum VF-39 and were synthetically transformed into 2-hydroxy-3-(allyloxy)propyl group-modified Cys (allyl-Cys) using allyl glycidyl ether (AGE) (Scheme 1(a)). Allyl-Cys were characterized using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and ¹ H nuclear magnetic resonance (NMR) spectroscopic analysis. Cys-bonded stationary phase was prepared by a chemical modification. Among the various chiral flavonoids, 4'-hydroxyflavanone and isosakuranetin were successfully separated using Cys-CSP. Cys-CSP is able to enantioseparate specific chiral compounds. It is suggested that the Cys-CSP method could be an effective approach for a rational application of chiral technology on pharmaceutical industry. Because of the potent application of this modified Cys in HPLC chiral separation, further research efforts will be directed to investigating the enantioseparation of various chiral molecules such as drugs using differently derivatized Cys-CSP.