Interactions of Indole Derivatives with β-Cyclodextrin: A Quantitative Structure-Property Relationship Study.

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.

Molecular recognition of indole derivatives by polymers imprinted with indole-3-acetic acid: a QSPR study.

Three molecularly imprinted polymers (MIPs) were prepared using the phytohormone indole-3-acetic acid (IAA) as a template molecule, 4-vinylpyridine (MIP-1 and MIP-2) or N,N-dimethylaminoethyl methacrylate (MIP-3) as functional monomers, ethylenglycol dimethacrylate as a cross linker and acetonitrile (MIP-1), a methanol-water mixture (MIP-2) or chloroform (MIP-3) as porogens. Retention factors for IAA and 29 indole derivatives were determined by high-performance liquid chromatography, using the molecularly imprinted polymers as stationary phases and acetonitrile as an eluent. High correlations between selectivity factors of above mentioned polymers indicate that their retention mechanisms are basically the same.

Binding of ring-substituted indole-3-acetic acids to human serum albumin.

The plant hormone, indole-3-acetic acid (IAA), and its ring-substituted derivatives have recently attracted attention as promising pro-drugs in cancer therapy. Here we present relative binding constants to human serum albumin for IAA and 34 of its derivatives, as obtained using the immobilized protein bound to a support suitable for high-performance liquid chromatography. We also report their octanol-water partition coefficients (logK(ow)) computed from retention data on a C(18) coated silica gel column.

Binding behavior of amino acid conjugates of indole-3-acetic acid to immobilized human serum albumin.

The affinity of indole-3-acetic acid (IAA), indole-3-propionic acid, indole-3-butyric acid and 24 of their amino acid conjugates to immobilized human serum albumin, as expressed by the retention factor k (determined by HPLC), was dependent on (1) lipophilicity, (2) chirality and (3) functional groups in the amino acid moiety; in some cases conformation plays an additional role. Two lipophilicity-related parameters afforded quantitative correlations with k: retention on a C18 reversed-phase column (experimental approach) and the distance between the hydrophilic and hydrophobic poles of the molecules (in silico approach). Most compounds examined are possible metabolic precursors of IAA, an experimental tumor therapeutic.

Modeling the octanol-water partition coefficients by an optimized molecular connectivity index.

A procedure that makes it possible to generate a coherent model for prediction of the octanol-water partition coefficient within the molecular connectivity formalism was put forward. The method is based on the optimization of weights for corresponding skeletal atoms and is similar to the method for calculation of a variable connectivity index proposed by Randić. In contrast to Randić's method, we incorporate in the algorithm the possibility that the contribution of a term describing a carbon-heteroatom bond may be negative.

Absorption and fluorescence spectra of ring-substituted indole-3-acetic acids.

The absorption and fluorescence spectra of indole-3-acetic acid (1), a plant growth regulator (auxin) and experimental cancer therapeutic, 29 ring-substituted derivatives and the 7-aza analogue (1H-pyrrolo[2,3b]pyridine-3-acetic acid) are compared. Two to four absorbance maxima in the 260-310-nm range are interpreted as overlapping vibronic lines of the 1La<--1A and 1Lb<--1A transitions. Two further maxima in the 200-230-nm region are assigned to the 1Ba<--1A and 1Bb<--1A transitions.