Direct HPLC enantioseparation of chemopreventive chiral isothiocyanates sulforaphane and iberin on immobilized amylose-based chiral stationary phases under normal-phase, polar organic and aqueous conditions

Alessia Panusa; Alessia Rosetti; Claudio Villani; Roberto Cirilli

doi:10.1016/j.talanta.2020.121151

Direct HPLC enantioseparation of chemopreventive chiral isothiocyanates sulforaphane and iberin on immobilized amylose-based chiral stationary phases under normal-phase, polar organic and aqueous conditions

Talanta. 2020 Oct 1:218:121151. doi: 10.1016/j.talanta.2020.121151. Epub 2020 May 11.

Authors

Alessia Panusa¹, Alessia Rosetti², Claudio Villani³, Roberto Cirilli⁴

Affiliations

¹ National Centre for the Control and Evaluation of Medicines, Chemical Medicines Unit, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy.
² National Centre for the Control and Evaluation of Medicines, Chemical Medicines Unit, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy; Department of Chemistry and Technology of Drugs, Sapienza University of Rome, 00185, Rome, Italy.
³ Department of Chemistry and Technology of Drugs, Sapienza University of Rome, 00185, Rome, Italy.
⁴ National Centre for the Control and Evaluation of Medicines, Chemical Medicines Unit, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy. Electronic address: roberto.cirilli@iss.it.

PMID: 32797906
DOI: 10.1016/j.talanta.2020.121151

Abstract

Sulforaphane and iberin are promising chemopreventive chiral phytochemicals. The chirality of these organic isothiocyanates is due to the presence of a stereogenic sulfur atom. Investigations of the effectiveness of single enantiomers as chemoprotective agents highlight the key role played by sulfur chirality on biological activity. The predominant native (R)-enantiomer is active whereas the (S)-counterpart is inactive or poorly active. Here, we provide an enantioselective method for the direct and complete resolution of both chiral sulfoxides by high-performance liquid chromatography on immobilized amylose-derived chiral stationary phases. A set of five different columns was investigated utilizing normal-phase, polar organic and aqueous conditions. The effect of the composition of mobile phase on enantioselectivity and retention was carefully evaluated. U-shape retention maps, which are indicative of a double and competitive hydrophilic interaction liquid chromatography and reversed-phase liquid chromatography retention mechanism, were established by recording the retention factors of the enantiomers of sulforaphane on the Chiralpak IA-3 and Chiralpak IG-3 chiral stationary phases varying progressively the water content in the water-acetonitrile mobile phases.

Keywords: Amylose-based CSPs; Enantioselective HPLC; Hydrophilic interaction liquid chromatography; Iberin; Sulforaphane.