title: A study of the phototoxicity of lemon oil.
abstract: Lemon oil contains furocoumarin derivatives and is known to cause phototoxicity. In this study, lemon oil was fractionated, and its phototoxic activity was measured by means of a biological assay. The substances producing phototoxicity were identified by high-performance liquid chromatography as being oxypeucedanin and bergapten. The phototoxic potency of oxypeucedanin was only one-quarter of that of bergapten. However, the amounts of these two phototoxic compounds present in lemon oils produced in different regions of the world varied by a factor of more than 20 (bergapten, 4-87 ppm; oxypeucedanin, 26-728 ppm), and their ratio was not constant. The two compounds accounted for essentially all of the phototoxic activity of all lemon-oil samples. Among various other citrus-essential oils investigated, lime oil and bitter-orange oil also contained large amounts of oxypeucedanin. Oxypeucedanin was found to elicit photopigmentation on colored-guinea-pig skin without preceding visible erythema.
mesh_terms: D000078223:5-Methoxypsoralen; D000818:Animals; D002957:Citrus / Q000032:analysis*; D003374:Coumarins / Q000633:toxicity; D011564:Furocoumarins / Q000633:toxicity; D006168:Guinea Pigs; D008730:Methoxsalen / Q000032:analysis; D009822:Oils, Volatile / Q000032:analysis / Q000633:toxicity*; D010787:Photosensitivity Disorders / Q000139:chemically induced*; D010859:Pigmentation Disorders / Q000139:chemically induced; D012867:Skin / Q000473:pathology
chemical_list: D003374:Coumarins; D011564:Furocoumarins; D009822:Oils, Volatile; D000078223:5-Methoxypsoralen; C030123:coumarin; D008730:Methoxsalen