Abstract
High-performance liquid chromatographic (HPLC) and subcritical fluid chromatographic (SFC) separations of the enantiomers of structurally diverse, basic ß-carboline, tetrahydroisoquinoline and benzazepine analogues of pharmacological interest were performed applying chiral stationary phases (CSPs) based on (i) neutral polysaccharides- and (ii) zwitterionic sulfonic acid derivatives of Cinchona alkaloids. The aim of this work was to reveal the influence of structural peculiarities on the enantiorecognition on both types of CSP through the investigation of the effects of the composition of the bulk solvent, the structures of the chiral analytes (SAs) and chiral selectors (SOs) on retention and stereoselectivity. As a general tendency, valid for all polysaccharide SOs studied, the increase of the concentration of the apolar component in the mobile phase (n-hexane for LC or liquid CO2 for SFC) was found to significantly increase retention, which in most cases, was accompanied with increased selectivity and resolution. In a way, similar behaviour was registered for the zwitterionic SOs. In polar ionic mode employing eluent systems composed of methanol and acetonitrile with organic acid and base additives, moderate increases in retention factor, selectivity and resolution were observed with increasing acetonitrile content. However, under SFC conditions, an extremely high increase in retention was observed with increased CO2 content, while selectivity and resolution changed only slightly. Thermodynamic parameters derived from temperature dependence studies revealed that separations are controlled by enthalpy.
Highlights
Harmane, harmine and harmaline ß-carboline alkaloids, e.g. (+)-harmicine, exhibit a wide range of pharmacological properties, including antimicrobial and anti-HIV activities [1,2,3], whereas yohimbine is an antagonist of α2-receptors located both presynaptically and postsynaptically on noradrenergic neurons [3]
The main objective of the present paper is to reveal some general tendencies of structural peculiarities of the enantiomers of pharmacologically interesting analytes such as ß-carboline, tetrahydroisoquinoline and benzazepine analogues with respect to their enantioseparation on the above-mentioned SOs used under Liquid chromatographic (LC) and subcritical fluid chromatographic (SFC) conditions
In our study we have focused on the effects of the variation of mobile phase composition in LC and SFC on the retention, selectivity and resolution of the enantiomeric basic structures of the chiral analytes (SAs) in context of the structurally entirely divergent types of SOs
Summary
Harmine and harmaline ß-carboline alkaloids, e.g. (+)-harmicine, exhibit a wide range of pharmacological properties, including antimicrobial and anti-HIV activities [1,2,3], whereas yohimbine is an antagonist of α2-receptors located both presynaptically and postsynaptically on noradrenergic neurons [3]. The ß-carboline skeleton is present in numerous naturally occurring alkaloids, such as the harman family, including eudistomines and manzamines, or canthines bearing an additional fused cycle. These compounds initially attracted interest because of their potent psychoactive and hallucinogenic abilities [1]. Benzazepine derivatives have important biological properties such as anti-depressant, anti-hypertensive, anti-ischaemic and anorectic activity They are antihistamine agents, AChE inhibitors, TRPV1 antagonists and they are used in the treatment of hyponatremia [8]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
