Enantiomeric Separation of Indole-3-Propanamide Derivatives by Using Supercritical Fluid Chromatography on a Polysaccharide-Based Chiral Stationary Phase

Abstract

Thirteen pairs of I3P enantiomers were screened using nine polysaccharide chiral stationary phases and three different mobile phases. The purification strategy for 13 pairs of I3P enantiomers were designed and optimized considering enantiomeric purity and enrichment of isomers. Out of 13 I3P derivatives which were screened using supercritical fluid chromatography, 10 derivatives displayed excellent baseline separation using a Lux Cellulose-4 column and their resolution from higher to lower order of I3P-11, 13, 4, 12, 2, 1, 9, 3, 7 and 8 derivatives whereas in case of Lux Cellulose-2 column, the moderate separation was achieved as compared to Cellulose-4 in the order I3P-5, 6 and 10 derivatives. Excellent enantiomeric separations and retentions for all 13 I3P enantiomer derivatives were obtained in Cellulose-4 and Cellulose-2 columns in presences of methanol as organic modifier without any additives except in the case of I3P 12 enantiomer. The absolute stereochemical assignment of the purified isomers was determined through an optical rotation study. Among the series of I3P derivatives, I3P-5 showed potent antioxidant activity against catalase with an IC50 value of 13.78μM. Further molecular docking, MM/GBSA and molecular dynamics studies revealed that the I3P-5 derivatives effectively bind to catalase with a docking score of -5.41kcal/mol. Which validated chiral docking and indicated great potential for enantiomeric separation in drug discovery and present studies (R)-enantiomer preferentially depicts good binding capacity with catalase.