In vitro interactions of coumarins with iron

Mladěnka, Přemysl; Macáková, Kateřina; Zatloukalová, Libuše; Rehakova, Zuzana; Singh, Brajendra K.; Prasad, Ashok K.; Parmar, Virinder S.; Jahodár, L; Hrdina, Radomír; Saso, Luciano

doi:10.1016/j.biochi.2010.03.025

Cited by 80 publications

(72 citation statements)

References 33 publications

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“…4B), which is indicative for Fe-catechol complexes (McBryde, 1964;Salama et al, 1978). In fact, not only coumarins, but also other phenols have been shown to chelate Fe(III) in vitro if they contain two adjacent hydroxy groups (catechol moiety; Andjelkovic et al, 2006;Mladenka et al, 2010). Among the coumarins identified in this study, esculetin and fraxetin harbor such a moiety, whereas in others, the hydroxy group is either methylated (scopoletin; Fig.…”

Section: F69h1 Is Required For the Synthesis Of Coumarins With Fe Mobmentioning

confidence: 68%

“…Importantly, our Fe(III) mobilization assays were performed at high pH, indicating that Fe(III) mobilization and chelation by coumarins is not sensitive to alkaline pH. Although some phenolics are also able to reduce Fe(III), the efficiency of this reaction is significantly decreased under high pH (Römheld and Marschner, 1983;Mladenka et al, 2010). Thus, we assume that Fe(III) reduction by coumarins may not be relevant under alkaline conditions.…”

Section: F69h1 Is Required For the Synthesis Of Coumarins With Fe Mobmentioning

confidence: 91%

“…Although in both cases it was shown that these compounds are important to prevent the development of leaf chlorosis, neither study explored how these compounds improved the plants' ability to cope with limited Fe availability. In vitro studies have shown that phenolic compounds can chelate and reduce Fe(III) (Andjelkovic et al, 2006;Mladenka et al, 2010). However, it is noteworthy that the overall reducing capacity of the phenolics released by Fe-deficient roots is many orders of magnitude below that of the ferric chelate reductase (Römheld and Marschner, 1983).…”

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confidence: 99%

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Feruloyl-CoA 6'-Hydroxylase1-Dependent Coumarins Mediate Iron Acquisition from Alkaline Substrates in Arabidopsis

Schmid¹,

Giehl²,

Döll³

et al. 2013

PLANT PHYSIOLOGY

286

383

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Section: F69h1 Is Required For the Synthesis Of Coumarins With Fe Mobmentioning

confidence: 68%

Section: F69h1 Is Required For the Synthesis Of Coumarins With Fe Mobmentioning

confidence: 91%

mentioning

confidence: 99%

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Feruloyl-CoA 6'-Hydroxylase1-Dependent Coumarins Mediate Iron Acquisition from Alkaline Substrates in Arabidopsis

Schmid¹,

Giehl²,

Döll³

et al. 2013

PLANT PHYSIOLOGY

286

383

View full text Add to dashboard Cite

“…Iron chelating properties have been shown for both coumarins and flavins. 17,18 It is interesting to note that at both feruloyl-CoA and riboflavin a hydroxyl group is added in the last step of the biosynthetic pathway that likely improves solubility of the secreted compound. Alternatively, the main function of IBCs could be related to the reduction of ferric iron, acting as long distance electron shuttle (Fig.…”

mentioning

confidence: 99%

Reduction-based iron uptake revisited

Rodríguez-Celma

Schmidt

2013

Plant Signaling & Behavior

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With the exception of the grasses, plants rely on a reduction-based iron (Fe) uptake system that is compromised by high soil pH, leading to severe chlorosis and reduced yield in crop plants. We recently reported that iron deficiency triggers the production of secondary metabolites that are beneficial for Fe uptake in particular at high external pH when iron is present but not readily available. The exact function of these metabolites, however, remains enigmatic. Here, we speculate on the mechanism by which secondary metabolites secreted by roots from Fe-deficient plants improve Fe acquisition. We suggest that the production and excretion of Iron Binding Compounds (IBCs) constitute an integrative, pH-insensitive component of the reduction-based iron uptake strategy in plants.Although iron (Fe) is generally present in large amounts, in aerobic soils Fe tends to form oxyhydrates of low solubility, in particular at neutral or high pH. When atmospheric oxygen increased as a result of the evolution of photosynthesis, plants were forced to evolve strategies that improve Fe acquisition, which was chiefly achieved by increasing the solubility of immobile Fe pools. All plant species except the grasses have employed a mechanism that includes reduction of ferric chelates, mediated by a plasma membrane-bound oxidoreductase (FRO2 in Arabidopsis). The reduction of Fe(III) weakens the stability of the chelate and the released Fe(II) is taken up by a ZIP family transporter (IRT1).2 A drawback of this strategy is that it works best at a slightly acidic pH and is strongly impaired in soils with high pH.3 This is partly counteracted by induction of a P-type H + -ATPase that provides a favorable pH environment (AHA2). 4Excretion of organic compounds, mainly phenolics or flavins, have been associated with the Fe deficiency response since the early seventies, 5,6 but were later considered to be of minor importance and, with some notable exceptions (e.g., the massive production of riboflavin and riboflavin derivatives by some species), 7,8 were largely neglected in studies related to iron acquisition processes in model species such as Arabidopsis. Nevertheless, the frequent observation of this phenomenon led to speculations on the function of these compounds in Fe acquisition, comprising effects on the microbiome in the rhizosphere, a function (for flavins) in electron transport during the reduction of Fe(III), chelation of Fe, and chemical reduction of Fe(III). The first clear-cut evidence for a function of Fe deficiency-induced root secretions in Fe uptake was provided by Jin et al. showing that phenolics secreted by red clover roots facilitated the acquisition of Fe bound to anionic residues in the apoplast.9 Similarly, transgenic rice plants overexpressing the phenolic efflux transporter PEZ1 grew better on soils with high pH and poor Fe solubility.10 In Arabidopsis, robust induction of the phenylpropanoid pathway, both at the transcript and protein levels, 11,12 indicating that in roots of Fe-deficient plants phenolic compounds ar...

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“…Structures of apigenin (Ap), chrysin (Ch), daidzein (Dn) and quercetin (Qn) likely related to their antioxidant properties [3,4]. The structural differences of flavones significantly affect their absorption, metabolism, and bioactivities [5,6].…”

mentioning

confidence: 99%