Two Nematicidal Substances from Roots ofCirsium japonicum

Guided by the bioassay with Bursaphelenchus lignicolus described in the preceding paper, two nematicidal substances were isolated from roots of Cirsium japonicum and identified with tridec-1-ene-3,5,7,9,11-pentayne and 9,10-epoxy-heptadec-16-ene-4,6-diyn-8-ol. These two compounds completely inhibited propagation of the nematode at a dose of 16 µg and 250 µg, respectively. 1-Phenylhepta-1,3,5-triyne and 2-phenyl-5-(1′-propynyl)-thiophene (from Coreopsis lanceolata) and cis-dehydromatricaria ester (from Solidago altissima) also inhibited the propagation at a dose of 110 εg.