The Proton Nuclear Magnetic Resonance Spectroscopy in Following Ozone Reaction with Unsaturated Fatty Acids M. Díaz, F. Hernández, I. Alvarez, H. Velez(1), O. Ledea, J. Molerio. Ozone Research Center, Cuba. 1 - National Center for Scientific Research, Cuba. Unsaturated fatty acids are essential components of biological membranes. In this paper, ozonolysis in vitro of unsaturated fatty acids with addition of water or ethanol have been studied by Proton Nuclear Magnetic Resonance (1H NMR) at 250 MHz in order to investigate if this technique can be used to follow up ozone reaction with biological melecules. The ozonolysis of methyl oleate (one unsaturated bond) showed that signal intensities from formed ozonides were increased with ozone concentration increments. However, the signal intensities with addition of water were higher than those in ethanol addition. Signal intensities from olefinic double bonds were found to decrease with the increment in ozonide signals and was present a higher consumption of these bonds in water than in ethanol addition. When ozonolysis of methyl linoleate (two unsaturated bonds) was performed, signal intensities values from ozonide formed in both medium were several times greater than those observed with methyl oleate; and signal intensities values from olefinic groups disappeared more quickly. Vitamin E added in a non-competitive manner results in the same observed pattern. Thus, a correspondence in the behavior of these signals is observed, and more important is the observation that they reflect the proportionality between rate reaction and the number of double allylic positions present in the substrate molecule. Signals from aldehydes formation were poorly detected at lower ozone concentrations. We suggest that the evaluation of ozonide and olefinic double bond signals from 250 MHz 1H NMR can be an useful tool in assessing ozone reaction with biomolecules and perhaps in ozone therapy follow up. Source: 2nd International Symposium on Ozone Applications Havana, Cuba - Mach 24-26, 1997.