Nematicidal Constituents from the Essential Oil of Chenopodium Ambrosioides Aerial Parts

Essential oil of Chinese medicinal herb, Chenopodium ambrosioides aerial parts was found to possess nematicidal activity against the root‐knot nematodes, Meloidogyne incognita. The essential oil of C. ambrosioides was obtained by hydrodistillation and analyzed by gas chromatography‐mass spectrometry (GC‐MS). A total of 27 components of the essential oil were identified. The principal compounds in C. ambrosioides essential oil were (Z)‐ascaridole (27.27%), ρ‐cymene (19.05%), isoascaridole (14.75%), α‐pinene (6.33%) and α‐terpinene (5.12%). Bioactivity‐guided chromatographic separation of the essential oil on repeated silica gel columns led to isolate three volatile components ((Z)‐ascaridole, ρ‐cymene and isoascaridole) from the essential oil. The essential oil and (Z)‐ascaridole exhibited strong nematicidal activity against M. incognita with LC50 values of 49.55 μg/mL and 32.79 μg/mL, respectively. ρ‐Cymene and isoascaridole also possessed nematicidal activity against M. incognita with LC50 values of 435.89 μg/mL and 1323.51 μg/mL, respectively but weaker than the crude essential oil.