Wild Parsnip (Pastinaca sativa)-Induced Photosensitization
Wild parsnip (Pastinaca sativa) has been associated with livestock and human photosensitization. An investigation of a natural occurrence of photosensitization of grazing horses identified wild parsnip as a possible cause. HPLC-MS and MS/MS analysis of this plant identified five furanocoumarins i.e., xanthotoxin, bergapten, isopimpinellin, imperatorin and a putative methoxyimperatorin. Goats fed this wild parsnip were largely unaffected. Xanthotoxin was not detected in the serum of parsnip-fed goats or in the serum of goats dosed orally or intravenous with purified xanthotoxin. Cutaneous application produced severe photodermatitis in goats and a horse consistent with topical exposure as the likely route to produce wild parsnip-induced photosensitivity. Wild parsnip-induced superficial necrotizing dermatitis was consistent with photodermatitis with no evidence of other allergic or inflammatory components.
Stegelmeier, B.L., S.M Colegate, D.E. Knoppel, K.A. Rood, and M.G. Collett. (2019) Wild parsnip (Pastinaca sativa) – induced photosensitization. Toxicon, vol 167. https://doi.org/10.1016/j.toxicon.2019.06.007