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Explaining photodermatosis: cyclopentenone vs. alpha-methylene-gamma-lactone natural products
B B Patel1, T G Waddell, R M Pagni
1Department of Chemistry, University of Tennessee at Chattanooga, Chattanooga, TN 37403, USA.
Abstract:
The possible role of cyclopentenone-containing sesquiterpene lactones in the cause of photochemical chronic actinic dermatitis (CAD) is examined in light of recent reports that the alpha-methylene-gamma-lactone group of these natural products forms 2+2 photoadducts with the DNA base thymine. Neither cyclopentenone nor tenulin (a cyclopentenone-containing sesquiterpene lactone) form such photoadducts with thymine either with sunlight or a UV lamp (300 nm). In contrast, alpha-methylenebutyrolactone readily forms the 2+2 photoadduct with thymine in sunlight. Thus, the photochemical role of the alpha-methylene-gamma-lactone group (rather than cyclopentenone) is strongly implicated in the CAD disease.
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