2114 Oxidative Consumption of Biomolecules by Therapeutic Levels of Ozone
M. TURNER, M. GROOTVELD, C. SILWOOD, and E. LYNCH, Queens University, Belfast, United Kingdom

Objectives: The potent microbicidal actions of ozone (O3) are well known and recent investigations have demonstrated its potential employment as a therapeutic agent in the treatment of dental caries. This oxidant is extremely reactive towards carious dentin biomolecules, and such reactions are likely to be of relevance to its therapeutic activity. Therefore, in this study we have employed high resolution proton (1H) nuclear magnetic resonance (NMR) spectroscopy to determine the nature and extent of the oxidation of biomolecules known to be present in carious dentin, plaque and

saliva.

Methods: Aqueous solutions containing sodium pyruvate, a-D-glucose, L-cysteine and L-methionine (5.00 mM) were prepared in 40.0 mM phosphate buffer (pH 7.00) which was rigorously deoxygenated with argon gas prior to use. 5.00 ml aliquots of these solutions were treated with O3 [1] for a period of 10 s (equivalent to a delivery of 4.48 mmol. of this oxidant). These experiments were conducted in triplicate. Matching de-oxygenated solutions of these biomolecules untreated with O3 served as controls.

Results: Attack of O3 on a-D-glucose gave rise to formate as a major product, i.e. 1.21 ± 0.11 mM (mean ± s.e.) generated, and treatment of pyruvate with this oxidant produced acetate and CO2 via an oxidative decarboxylation process (93 ± 4 % yield under our experimental conditions). Moreover, the amino acid volatile sulphur

compound (VSC) precursors cysteine and methionine were converted to their corresponding primary oxidation products cystine (100% yield) and methionine sulphoxide (98 ± 2 % yield) respectively.

Conclusions: Multicomponent analysis of appropriate chemical model systems provides valuable molecular information regarding the reactivity of O3 towards biomolecules present in the oral environment. For example, oxidation of the VSC precursors cysteine and methionine provides evidence for the ability of O3 to combat oral malodour.

[1] HealOzone Unit, CurOzone, U.S.A.

Seq #195 - Anticariogenic Foods and Restorations
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