Free radical-scavenging activity and DNA damaging potential of auxins IAA and 2-methyl-IAA evaluated in human neutrophils by the alkaline comet assay.

Auxins, of which indole-3-acetic acid (IAA) is the most widespread representative, are plant hormones. In addition to plants, IAA also naturally occurs in humans in micromolar concentrations. In the presence of peroxidase, indolic auxins are converted to cytotoxic oxidation products and have thus been proposed for use in gene-directed enzyme/prodrug tumor therapy.

Isolation of novel indole-3-acetic acid conjugates by immunoaffinity extraction.

An analytical protocol for the isolation and quantification of indole-3-acetic acid (IAA) and its amino acid conjugates was developed. IAA is an important phytohormone and formation of its conjugates plays a crucial role in regulating IAA levels in plants. The developed protocol combines a highly specific immunoaffinity extraction with a sensitive and selective LC-MS/MS analysis.

Auxin amidohydrolases from Brassica rapa cleave the alanine conjugate of indolepropionic acid as a preferable substrate: a biochemical and modeling approach.

Two auxin amidohydrolases, BrIAR3 and BrILL2, from Chinese cabbage [Brassica rapa L. ssp. pekinensis (Lour.

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.