Phototoxicity in Heracleum sphondylium

Abstract

Phototoxicity of leaf extracts of nine subspecies of Heracleum sphondylium lat. was tested using Candida albicans is a test organism and the results were roughly quantified. The leaves of the subspecies sphondylium and sibircum were usually non-phototoxic. Variation was observed within the subspecies granatense and ternatum. The subspecies alpinum, transsilvanicum, pyre-naicum, montanum and orsinii were moderately to strongly phototoxic. Morphologically variable populations varied correspondingly in the degree of phototoxicity. Fruits were phototoxic in all taxa studied and roots in all taxa but subsp. alpinum. Evidence from thin-layer chromatography suggests that phototoxicity may be caused by the 6,7-furocoumarins (psoralens) xanthotoxin, bergapten, imperatorin and a non-identified compound. Ecological effects and taxonomical implications are briefly discussed.

Key Word Index

Heracleum sphondylium - Apiaceae (Umbelliferae) - Phototoxicity - Furocoumarins - Candida Test.