Indole-3-methanol—a metabolite of indole-3-acetic acid in pea seedlings

Magnus, Volker; Iskrić, Sonja; Kveder, S.

doi:10.1007/bf00386759

Cited by 34 publications

(19 citation statements)

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“…The ester was also Indole-3-Methanol, 3-Methoxymethylindole, and 3,3'-Diindolylmethane. It is known that indole-3-methanol spontaneously dimerizes to give 3,3'-diindolylmethane (29) and also condenses with the methanol used for the extraction of plant metabolites to yield 3-methoxymethylindole (13). In this work, the latter compound was preferentially detected and taken as evidence for the presence of indole-3-methanol in the incubated plant material.…”

Section: Methodsmentioning

confidence: 76%

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Metabolism of Tryptophan, Indole-3-acetic Acid, and Related Compounds in Parasitic Plants from the Genus Orobanche

Magnus¹,

Šimaga²,

Iskrić³

et al. 1982

Plant Physiol.

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Metabolic reactions involving the aliphatic side chain of tryptophan were studied in the holoparasitic dicotyledonous plants Orobanche graciis Sm., 0. haea Baumg., and 0. ramosa L. Unlike known autotrophic plants, the parasite metabolized L-tryptophan directly to indole-3-carboxaldehyde, which was further converted to indole-3-methanol and indole-3-carboxylic acid. Independently, these metabolites were also formed from D-tryptophan, tryptamine, indole-3-lactic acid, and indole-3-acetic acid. As in autotrophic plants, tryptophan and tryptamine were also converted, via indole-3-acetaldehyde, to indole-3-acetic acid, indole-3-ethanol, and its glucoside. free from adhering soil and stored overnight. The plant material was cut into sections about 1 cm in length. Boiled plant material was prepared in flasks immersed in a boiling water bath for 30 min.Incubation Procedure. Substrate solutions (1 ml/g of plant material) were prepared in 0.067 M KH2PO4 (pH 4.5) at approximate concentrations of 1 mg/ml for D-and L-tryptophan, tryptamine hydrochloride, indole-3-lactic acid, and tryptophol, and 0.1 mg/ml for IAA, indole-3-acetaldehyde, indole-3-methanol, indole-3-carboxaldehyde, and indole-3-carboxylic acid. Inhibitors were added to the substrate solutions at 1 to 2 mg/ml for cycloserine and semicarbazide hydrochloride and 0.1 mg/ml for KCN. These solutions were vacuum-infiltrated (at 20 mm Hg) into the plant sections. The sections took up about one-quarter of the solutions, a great deal of which was retained in dead space, such as that in between bracts and in flower buds. Intemal substrate levels per g of metabolically active plant tissue are, thus, smaller than are those per ml of the external solutions by at least one order of magnitude. The plant material and the remaining substrate solutions were incubated separately at 22°C for 5 h, the latter with aeration.Prepurification of Plant Extracts. After incubation, the plant material was homogenized in a 2-fold (w/v) amount of methanol.The homogenate was filtered, and the residue was reextracted. The combined filtrates were stored at -10°C until used. They were then concentrated in vacuo to a few ml; methanol (50 ml) was added, and the mixture was left at -10°C overnight. The precipitate was discarded, and the filtrate was concentrated in vacuo, adjusted to 10 ml with methanol, and extracted, once with 30 ml and a second time with 15 ml of benzene. The combined extracts were evaporated and the residue extracted with 5 x

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Section: Methodsmentioning

confidence: 76%

“…The prepurified samples were concentrated to 0.5 to 1 ml and applied to a column (i. The reliability of this method has been shown previously (13).…”

Section: Methodsmentioning

confidence: 91%

Metabolism of Tryptophan, Indole-3-acetic Acid, and Related Compounds in Parasitic Plants from the Genus Orobanche

Magnus¹,

Šimaga²,

Iskrić³

et al. 1982

Plant Physiol.

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“…A previously described method was used (10,(13)(14)(15). Briefly, organic solvent-insoluble constituents in the plant extracts were precipitated with methanol and benzene:methanol (5:1, v/v).…”

mentioning

confidence: 99%

“…The following compounds which might have been expected to participate in tryptophol metabolism, and which should mostly be detectable by the methods used (13,15) were absent in at least 80% of the species examined:…”

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Metabolism of Tryptophol in Higher and Lower Plants

Laćan¹,

Magnus²,

Šimaga³

et al. 1985

Plant Physiol.

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Bacteria, thallophytes, and seed plants (107 species), supplied with exogenous indole-3-ethanol (tryptophol), formed one or more of the following metabolites: O-acetyl tryptophoL an unknown tryptophol ester (or a set of structurally closely related esters), tryptophol glucoside, tryptophol plactoside, indole-3-acetic acid (IAA), and indole-3-carboxylic acid. The unknown ester was formed by all species exAmined; 0-acetyl tryptophol appeared sporadically in representatives of most major taxonomic groups. Tryptophol galactoside was found in the algae Chlorella, Euglena, and Ochromoaas. The glucoside was formed by many eucaryotic plants, but not by bacteria; it was a significant tryptophol metabolite in vascular plants. IAA, if detectable at all, was usually a minor metabolite, as should be expected, if tryptophol oxidase responds to feedback inhibition by IAA. Indole-3-carboxylic acid, formed by a few fungi and mosses, was the only tryptophol metabolite detected which is likely to be formed via IAA.Indole-3-ethanol (tryptophol2) has been established as an endogenous plant constituent (6,19,23). It is also formed in vitro by preparations from bacteria, thallophytes, and seed plants from compounds supposed to participate in the biogenesis of IAA (e.g. 18,23). In fact, tryptophol appears to be in an oxidase-reductasemediated equilibrium with the IAA precursor, indole-3-acetaldehyde (5, 16). The oxidase has been isolated and found to be feedback inhibited by IAA (16). This points to the involvement of tryptophol in a mechanism stabilizing auxin levels in plants. Its in vivo significance has, however, remained unclear, because IAA concentrations necessary to inhibit the isolated tryptophol oxidase are larger than bulk concentrations of the hormone in plant tissues (16).Local IAA concentrations at points ofregulation may be higher than bulk concentrations. Also, removal of tryptophol oxidase from its natural subcellular environment may render the enzyme less sensitive to feedback inhibitors. For these reasons, we were looking for indications of regulated IAA formation from tryptophol in systems containing nondisrupted cell structures. Suspensions of unicellular plants and sections of multicellular plants were supplied with a large excess of tryptophol. In the absence of regulatory mechanisms, this might reasonably be expected to lead to drastically enhanced IAA levels. However, the majority of plants examined did not accumulate substantial amounts of 2 Abbreviations: tryptophol, indole-3-ethanol or 3-(2-hydroxyethyl)indole; Ve, elution volume.The most abundant tryptophol metabolites in bacteria, thallophytes, and seed plants were conjugates: esters and glycosides.MATERIALS AND METHODS Instrumentation. 'H NMR spectra were recorded at 100 MHz on a JEOL FX-100 Fourier-transform spectrometer. Chemical shifts (a) were recorded relative to tetramethylsilane. GC-MS was on a Hewlett-Packard 5985a instrument, using helium at 30 ml/ min as the carrier gas and electron impact ionization at 70 ev. Columns and temperature pr...

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Metabolism of Flavonoids

Barz¹,

Hösel²

1975

The Flavonoids

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Indole-3-methanol—a metabolite of indole-3-acetic acid in pea seedlings

Cited by 34 publications

References 15 publications

Metabolism of Tryptophan, Indole-3-acetic Acid, and Related Compounds in Parasitic Plants from the Genus Orobanche

Metabolism of Tryptophan, Indole-3-acetic Acid, and Related Compounds in Parasitic Plants from the Genus Orobanche

Metabolism of Tryptophol in Higher and Lower Plants

Metabolism of Flavonoids

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