title: Mechanism for 6-methylcoumarin photoallergenicity.
abstract: 6-Methylcoumarin (6-MC), a synthetic fragrance material, has been reported to be photoallergenic both in man and in guinea pigs. To elucidate the possible mechanism of photoallergenicity, 6-MC in ethanolic solution was exposed to 200 joules/cm2 of long-wavelength ultraviolet (UV) ranging from 320 to 400 nm for 16 hr, and was examined for its contact allergenicity by means of a modified guinea pig maximization test. Strong allergic responses were observed, indicating that UV plays a catalytic role in forming contact allergens during irradiation. The solution was fractionated to isolate and purify contact sensitizers by gel-permeation chromatography and high-performance liquid chromatography. By employing mass spectrometry and proton and carbon-13 nuclear magnetic resonance, mono- and diethyl esters of 6-MC dimer were compounds identified which showed allergic reactions in guinea pigs sensitized with UV-irradiated 6-MC.
mesh_terms: D000287:Administration, Topical; D000818:Animals; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003374:Coumarins / Q000633:toxicity*; D004890:Erythema / Q000209:etiology*; D005260:Female; D006168:Guinea Pigs; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010787:Photosensitivity Disorders / Q000209:etiology*; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D003374:Coumarins; C018096:6-methylcoumarin