title: Explaining photodermatosis: cyclopentenone vs. alpha-methylene-gamma-lactone natural products.
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.
authors: Department of Chemistry, University of Tennessee at Chattanooga, Chattanooga, TN 37403, USA.
authors: B B
authors: BB
authors: Patel
authors: T G
authors: TG
authors: Waddell
authors: R M
authors: RM
authors: Pagni
mesh_terms: D019659:Asteraceae; D003517:Cyclopentanes / Q000009:adverse effects* / Q000737:chemistry; D018736:DNA Adducts / Q000737:chemistry; D017454:Dermatitis, Photoallergic / Q000209:etiology*; D006801:Humans; D007783:Lactones / Q000009:adverse effects* / Q000737:chemistry; D010936:Plant Extracts / Q000009:adverse effects / Q000737:chemistry; D010946:Plants, Medicinal; D012717:Sesquiterpenes / Q000009:adverse effects* / Q000737:chemistry; D013472:Sunlight; D013941:Thymine / Q000737:chemistry
chemical_list: D003517:Cyclopentanes; D018736:DNA Adducts; D007783:Lactones; D010936:Plant Extracts; D012717:Sesquiterpenes; C011124:tenulin; C013905:cyclopentenone; D013941:Thymine