Allelopathic plants 27 : xanthium italicum Moretti.
Xanthium italicum Moretti is very competitive invasive weed originated from North America. It contains the xanthanolides, phenols, flavonoids and volatile compounds. Petri dish bioassays and pot experiments demonstrated that aqueous and ethanol extracts as well as plant residues of X. italicum were allelopathic to test plants. Besides these extracts also altered the soil properties and soil microorganisms. Bioactivity guided fractionation led to the isolation of 3 xanthanolides, i.e. xanthatin, xanthinin and xanthinosin, as the major active allelochemicals produced by this plant. Xanthium italicum also emits volatile organic compounds (VOCs) (limonene and other constituents detected in its volatile oil) these negatively affect the surrounding plants. Taken together, it is speculated that both direct and indirect allelopathic effects might be involved in facilitating the invasion success of X. italicum.