We investigated the direct chemistry of ozone on selected compounds found in plant epicuticular waxes by comparing the standard to the ozonized product using various analytical techniques. Ozone is a reactive environmental pollutant that impacts the structure of epicuticular waxes on plant leaves. It is unclear whether this change in structure is caused by a modification in plant biochemistry or due to ozone having a direct effect on the compounds found in the epicuticular waxes. Standards of 1-octadecanol, palmitic acid, oleanolic acid, flavanone, quercetin, ferulic acid and methyl decanoate were chosen to be representative of compounds found in epicuticular waxes. Each standard was individually exposed to excess amounts of ozone and reacted in a Teflon bottle for a prolonged period prior to analysis. Both the standard and the ozonized product were analyzed using 1H NMR, 13C NMR, CRAFT NMR, HSQC NMR and HPLC-QToF-MS. We found that the 1-octadecanol, oleanolic acid, quercetin and ferulic acid all showed evidence of reaction with ozone; however, the complexity of the spectra has made it difficult to deduce possible structures for the ozonized products. Further analysis of these compounds is required to determine the specific chemistry that is occurring at the molecular level, which in turn may help explain the macroscopic damage observed in epicuticular waxes in the presence of ozone.
Kochar, T. K. (2015). The Effects of Ozone on Compounds in Epicuticular Waxes in Plant Leaves (Undergraduate honors thesis, University of Redlands). Retrieved from https://inspire.redlands.edu/cas_honors/95