A 13C-N.m.r. study of the binding of ytterbium(III) to chondroitin sulphate and chondroitin

Balt, S.; Bolster, M. W. G. De; Visser-Luirink, Gesina

doi:10.1016/0008-6215(83)84001-4

Cited by 15 publications

(11 citation statements)

References 30 publications

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“…Regarding the coordination mode of the ligand in the 1 : 1 complex, we can assess that apart the COOH group, the ring C(5)-0-atom is involved in binding. This has been demonstrated on the basis of I3C-NMR spectra analysis for D-galacturonic acid by Izumi [31] and for D-glucuronic acid by de Bolster and coworkers [28]. The second dissociation step of these uronic acids in acidic solutions should have a negligible effect on the equilibria.…”

Section: Results and Discussion -Determination Of The Stability Consmentioning

confidence: 84%

“…-The trends observed in the log vl) and log (p2) values, together with the previously published NMR data [28] lead us to formulate the following conclusions on the structure of the complexes between lanthanide ions and simple uronic acids: a) the strong intermolecular sugar H-bonding network is rearranged upon the complex formation. b ) The differences in stability between D-galacturonate and D-glucuronate complexes, and within in Ln series, can be explained in terms of the steric hindrance of the C(4)-OH groups.…”

Section: Results and Discussion -Determination Of The Stability Consmentioning

confidence: 92%

“…It is consistent, however, with the I3C-NMR spectra analysis for the Yb3+/glucuronate system. De Bolster and coworkers [28] have indicated that one lanthanide ion binds preferentially two glucuronic-acid molecules in a symmetrical way. On the other hand, similarly to what was reported by Makridou et a/.…”

Section: Results and Discussion -Determination Of The Stability Consmentioning

confidence: 98%

“…4). For 1 :2 complexes, a 13C-NMR analysis of the Yb3'/~-glucuronate system point to the COO-group being the only one involved in coordination [28] (cf. right part of Fig.…”

Section: Results and Discussion -Determination Of The Stability Consmentioning

confidence: 99%

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Lanthanide‐Ion Complexation by D‐Glucuronic and D‐Galacturonic Acids

Fuks¹,

Bünzli

1993

Helvetica Chimica Acta

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To assess the potential of naturally occurring substances in the treatment of heavy-metal intoxication, the interaction between D-galacturonic and ~-glucuronic acids with several trivalent lanthanide ions has been studied in aqueous solutions by means of a spectrophotometric method (27"; 0 . 1~ NaC10,; pH 4.0). Values for the overall stability constants for [LnL] and [LnL,] (Ln = La, Ce, Pr, Nd, Gd, or Lu) complexes are presented and discussed.The interpretation of the data shows that, similarly to acetates, the COOH group coordinates metal ions in both [LnL] and [LnL,] complexes. The 1 :I complexation is supplemented by the ring C(5)-0-atom. Moreover, the C(4)-0-atom seems to play an important role in the steric hindrance of the chelating ligand molecules.Introduction. -Lanthanide ions are found in living organisms in trace amounts only, and they are considered to play no biological role 111. They interact, however, with biological materials in specific ways, which along with their unique magnetic and spectroscopic properties make them very informative substitution probes for Ca-, Mg-or Zn-containing biological materials [2]. Because of their chemical similarity, lanthanides may also act as substitution probes for the actinides, especially for those radioactive elements available only in submicroquantities.Foreign chemicals entering into the organism are usually converted into compounds that can be excreted. For heavy metals deposited into the organism, there is no physiological process that will eliminate them rapidly from the body. Their excretion rate is so slow that, in a normal life span, only a fraction of the deposited metals can be removed from the body. Events such as the Chernobyl fallout have stimulated studies leading to the development of new therapeutic methods for the removal of immobilized radioactive materials. The strategy for this removal has been mainly based on the use of high-affinity chelating agents which migrate preferentially to certain organs in vivo. A toxic metal bound to a constituent of living organisms (usually a protein) is transformed into a metal chelate which is readily excreted. It has long been known that the increase in stability constant of a metal complex parallels an increase in excretion rate [3-51.The majority of artificial chelating agents that are commerically available have been developed for purposes other than the removal of toxic metal ions from mammalian body. The most popular chelating agents EDTA (ethylenediaminetetraacetic acid) and DTPA (diethylenetriaminepentaacetic acid) have several COOH groups which are ionized under physiological conditions. Therefore, they cannot pass through cell membranes to any significant extent [6] [7]. As a result, EDTA and DTPA are very effective in

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Section: Results and Discussion -Determination Of The Stability Consmentioning

confidence: 84%

Section: Results and Discussion -Determination Of The Stability Consmentioning

confidence: 92%

Section: Results and Discussion -Determination Of The Stability Consmentioning

confidence: 98%

“…4). For 1 :2 complexes, a 13C-NMR analysis of the Yb3'/~-glucuronate system point to the COO-group being the only one involved in coordination [28] (cf. right part of Fig.…”

Section: Results and Discussion -Determination Of The Stability Consmentioning

confidence: 99%

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Lanthanide‐Ion Complexation by D‐Glucuronic and D‐Galacturonic Acids

Fuks¹,

Bünzli

1993

Helvetica Chimica Acta

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“…An accurate analysis of spectra of chondroitin-4-sulphate and chondroitin-6-sulphate structures in the presence of ytterbium(III) by nuclear magnetic resonance (NMR) was carried out by Balt et al [37]. In this study, it has been found that the structure of the ytterbium-polysaccharide complex in solution is similar to that of calcium-C4S, in which Ca ++ coordinates to the carboxylate group.…”

Section: Cs As Metal Ion Chelatormentioning

confidence: 91%

Chondroitin Sulphate: Antioxidant Properties and Beneficial Effects

Campo¹,

Avenoso²,

Campo³

et al. 2006

MRMC

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Most biological molecules exhibit more than one function. In particular, many molecules have the ability to directly/indirectly scavenge free radicals and thus act in living organisms as antioxidant. During oxidative stress, the increase of these molecules levels seems to be a biological response that in synergism with the other antioxidant defence systems may protect cells from oxidation. Among these structures, chondroitin sulphate is a biomolecule which has increasingly focused the interest of many research groups due to its antioxidant activity. This review briefly summarises the action of chondroitin sulphate in reducing molecular damage caused by free radicals and associated oxygen reactants.

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Nuclear magnetic resonance studies of polysaccharide structure and interactions

Casu¹

1985

Polysaccharides

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A 13C-N.m.r. study of the binding of ytterbium(III) to chondroitin sulphate and chondroitin

Cited by 15 publications

References 30 publications

Lanthanide‐Ion Complexation by D‐Glucuronic and D‐Galacturonic Acids

Lanthanide‐Ion Complexation by D‐Glucuronic and D‐Galacturonic Acids

Chondroitin Sulphate: Antioxidant Properties and Beneficial Effects

Nuclear magnetic resonance studies of polysaccharide structure and interactions

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