A study of the phototoxicity of lemon oil

Arch Dermatol Res. 1985;278(1):31-6. doi: 10.1007/BF00412492.


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

  • 5-Methoxypsoralen
  • Animals
  • Citrus / analysis*
  • Coumarins / toxicity
  • Furocoumarins / toxicity
  • Guinea Pigs
  • Methoxsalen / analysis
  • Oils, Volatile / analysis
  • Oils, Volatile / toxicity*
  • Photosensitivity Disorders / chemically induced*
  • Pigmentation Disorders / chemically induced
  • Skin / pathology


  • Coumarins
  • Furocoumarins
  • Oils, Volatile
  • 5-Methoxypsoralen
  • coumarin
  • Methoxsalen