Nematicidal activity of honokiol and magnolol isolated from magnolia tripetala

Ethyl acetate extract of the branches of Magnolia tripetala exhibited nematicidal activity against Bursaphelenchus xylophilus, Panagrellus redivivus and Caenorhabditis elegans. Two nematicidal phenolic compounds magnolol (1) and honokiol (2) were isolated from the extract based on bioassay-guided fractionation. The median lethal concentrations (LC50) of compounds 1-2 were 149.3 and 63.7 mg/l, respectively, against B. xylophilus, 74.5 and 75.9 mg/l, respectively, against P. redivivus, 64.7 and 57.8 mg/l, respectively, against C. elegans at 48 h.