Coumarins from Zosima absinthifolia seeds, with allelopatic effects

Zosima absinthifolia belongs to the Apiaceae family and is found in Iran, Turkey, Iraq and different countries of the Caucasus, Middle East and Central Asia. The fruits are used as food flavoring and as a food spice in Iran. In the present work, an n-hexane extract of the plant seeds was purified by vacuum liquid chromatography and preparative TLC for affording a furanocoumarin named imperatorin and two known coumarins, 7-prenyloxy coumarin and aurapten. The compound structures were elucidated by UV, 1H and 13C NMR data. Our results indicated that all tree compounds, especially imperatorin exhibited fungi toxic activity against Sclerotinia sclerotiorum, a common plant pathogen. The compounds also displayed phytotoxic effects and stunted seed germination, shoot and root growth of lettuce. It could be concluded that the purified compounds play allelopathic roles for the plant and could protect the plant against pathogens and competing herbs.