Radiolabelling studies of free radical reactions using muonium (the second hydrogen radioisotope): evidence of a direct antioxidant role for vitamin k in repair of oxidative damage to lipids

Rhodes, Christopher J.; Dintinger, Timothy C.; Moynihan, Humphrey A.; Reid, I. D.

doi:10.1002/1097-458x(200008)38:8<646::aid-mrc699>3.0.co;2-w

Cited by 9 publications

(3 citation statements)

References 10 publications

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“…repair in UVC-irradiated HMV-1 cells in a concentration of more than 900 µg ml −1 as well as MMTS, whereas, epigallocatechin exhibited a weak enhancing effect at 15 300 µg ml −1 . However, Vitamins A, C, E, and K (Vervoort et al, 1997;Rhodes et al, 2000) and catechin did not exhibit detectable thymine dimmer repair-enhancing activity in the concentrations at which their anti-oxidative effects were expected from references, suggesting that anti-oxidative activity is not necessarily related to the DNA repair-enhancing activity.…”

Section: Enhancement Of the Thymine Dimer Excision Repair Pathway By The Kefir Extractmentioning

confidence: 89%

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et al. 2002

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An aqueous extract of Kefir, fermented milk originally produced in the Caucasus mountains, suppressed morphological changes of human melanoma HMV-1 and SK-MEL cells and human normal fibroblastTIG-1 cells caused by UVC-irradiation, suggesting that UV damage can be suppressed by the Kefir extract. The addition of the Kefir extract after UVC-irradiation of HVM-1 cells resulted in a remarkable decrease in intracellular reactive oxygen species (ROS) which had been increased by UVC irradiation. The Kefir extract also stimulated unscheduled DNA synthesis and suppressed UVC-induced apoptosis of HMV-1 cells. A colony formation assay revealed that the Kefir extract rescued HMV-1 cells from cell death caused by UVC irradiation. The Kefir extract, as well as methyl methanethiosulfonate which is known to enhance the nucleotide excision repair (NER) activity, exhibited strong thymine dimer repair-enhancing activity. Epigalocatechin exhibited a weak NER activity but vitamins A, C, and E and catechin showed no NER activity. The thymine dimer repair-enhancing factors in the Kefir extract were heat-stable and assumed to be molecules with a molecular weight of less than 5000. The treatment of HMV-1 cells with the Kefir extract during or before UVC- irradiation also prevented the generation of ROS and thymine dimmer, and suppressed the apoptosis of HMV-1 cells, suggesting that application of Kefir can prevent UV damage.

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Section: Enhancement Of the Thymine Dimer Excision Repair Pathway By The Kefir Extractmentioning

confidence: 89%

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“…130 Since it is known that vitamin E and Vitamin K are lipophilic, and tend to accumulate in cell membranes, the kinetics of their potential "repair" reactions with 1,1,2-trimethylallyl [Me(MuCH 2 )C᎐ ᎐ C(Me)-CH 2 ؒ ] and 1acetoxy-2-propyl [MuCH 2 CH ؒ CH 2 OC(O)Me] radicals were measured. 131 These radicals are intended as models of, respectively, main-chain and glyceryl type radicals (damage sites), and were formed by Mu addition to 2,3-dimethylbuta-1,3-diene and to allyl acetate. The second order rate constants for these reactions are shown in Table 5.…”

Section: Vitamin K As a Potential Antioxidantmentioning

confidence: 99%

Muonium—the second radioisotope of hydrogen—and its contribution to free radical chemistry

Rhodes

2002

J. Chem. Soc., Perkin Trans. 2

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“…CH 2 OC(O)Me] radicals were studied. 58 These radicals are intended as models of, respectively, main-chain and glyceryl type radicals (damage sites), and are formed by Mu addition to 2,3-dimethylbuta-1,3-diene and to allyl acetate.…”

Section: Measurements Relevant To An Alternative Mode Of Lipid Damagementioning

confidence: 99%

8 Muon spectroscopy

Rhodes

2001

Annu. Rep. Prog. Chem., Sect. C

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The elusiveness of reactive free radicals poses great challenges for their investigation per se in most processes in which they have an intermediary role; this is true particularly in heterogeneous media. There are, however, methods available for the detection of radicals with enormous sensitivity and specificity which are given the collective acronym mSR (MuSR). All the MuSR methods rely upon the addition of the light hydrogen atom 'muonium' -a hydrogen atom with a radioactive positive muon as its nucleus, having a mass 1 9 that of a protium atom -to an organic substrate. In addition to its property of radioactive decay, the muon also has spin, and therefore experiments akin to those of conventional magnetic resonance experiments may be undertaken. Among the suite of methods thus encompassed is transverse-field MuSR (TF-MuSR), which is equivalent to ENDOR and yields the nucleus (muon) coupling directly, while the avoided level crossing (ALC) approach yields the magnitudes of the couplings from other nuclei present in a given radical, and also their relative signs (like TRIPLE does). Although these are resonance experiments, they do not require the application of external radiofrequency fields; however, radiofrequency experiments are possible, in which the analogies with more conventional magnetic resonance experiments are more direct. However, the experiments which are rendered possible by muons are unique, and have no practicable counterpart in more conventional techniques. In particular, the feature of single-particle-counting methods being used in combination with nuclear spins which are 100% polarised (i.e. vastly in excess of the Boltzmann factor!) permits unparalleled sensitivity regarding reactive radicals. Through the incisiveness of these methods, knowledge in the field of free radical chemistry has been gained that would be unachievable using the more established methods of EPR and its relatives.In consequence of these benefits, although my own background is in EPR (a topic which I have reviewed previously in this series), 1-3 my research group has become increasingly involved in the techniques of MuSR, especially in regard to determining the behaviour of radicals in catalytic systems and in heterogeneous environmental processes, and for the measurement of free radical reaction rates pertinent to biological membrane damage and repair. These are all topics whose investigation we could not have attempted without muons.

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Radiolabelling studies of free radical reactions using muonium (the second hydrogen radioisotope): evidence of a direct antioxidant role for vitamin k in repair of oxidative damage to lipids

Cited by 9 publications

References 10 publications

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Muonium—the second radioisotope of hydrogen—and its contribution to free radical chemistry

8 Muon spectroscopy

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