title: Interactions of Indole Derivatives with β-Cyclodextrin: A Quantitative Structure-Property Relationship Study.
abstract: Retention factors for 31 indole derivatives, most of them with auxin activity, were determined by high-performance liquid chromatography, using bonded β-cyclodextrin as a stationary phase. A three-parameter QSPR (quantitative structure-property relationship) model, based on physico-chemical and structural descriptors was derived, which accounted for about 98% variations in the retention factors. The model suggests that the indole nucleus occupies the relatively apolar cavity of β-cyclodextrin while the carboxyl group of the indole -3-carboxylic acids makes hydrogen bonds with the hydroxyl groups of β-cyclodextrin. The length and flexibility of the side chain containing carboxyl group strongly affect the binding of these compounds to β-cyclodextrin. Non-acidic derivatives, unlike the indole-3-carboxylic acids, are poorly retained on the column. A reasonably well correlation was found between the retention factors of the indole-3-acetic acids and their relative binding affinities for human serum albumin, a carrier protein in the blood plasma. A less satisfactory correlation was obtained when the retention factors of the indole derivatives were compared with their affinities for auxin-binding protein 1, a plant auxin receptor.
authors.affiliation: Department of Chemistry, Faculty of Agriculture, University of Zagreb, Svetošimunska 25, 10000 Zagreb, Croatia.
authors.forename: Milan
authors.initials: M
authors.lastname: Šoškić
authors.affiliation: Department of Chemistry, Faculty of Agriculture, University of Zagreb, Svetošimunska 25, 10000 Zagreb, Croatia.
authors.forename: Ivana
authors.initials: I
authors.lastname: Porobić
mesh_terms: D002851:Chromatography, High Pressure Liquid; D006801:Humans; D006860:Hydrogen Bonding; D007210:Indoleacetic Acids / Q000737:chemistry; D007211:Indoles / Q000737:chemistry*; D011336:Probability; D021281:Quantitative Structure-Activity Relationship; D015203:Reproducibility of Results; D012709:Serum Albumin / Q000737:chemistry; D013329:Structure-Activity Relationship; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D007210:Indoleacetic Acids; D007211:Indoles; D012709:Serum Albumin; D047392:beta-Cyclodextrins; C012382:indole-3-carboxylic acid; C031215:betadex