title: Composition of essential oil of Chinese Chenopodium ambrosioides and insecticidal activity against maize weevil, Sitophilus zeamais.
abstract: BACKGROUND
  In a screening programme for new agrochemicals from Chinese medicinal herbs, Chenopodium ambrosioides L. was found to possess strong fumigant activity against the maize weevil Sitophilus zeamais (Motsch.). Essential oil of C. ambrosioides was obtained by hydrodistillation, and the constituents were determined by GC-MS analysis. The active compounds were isolated and identified by bioassay-directed fractionation.
  
  
  RESULTS
  Five active compounds [(Z)-ascaridole, 2-carene, ρ-cymene, isoascaridole and α-terpinene] were isolated and identified from the essential oil from Chinese C. ambrosioides. The LC₅₀ values (fumigation) of the crude essential oils and the active compound (Z)-ascaridole against S. zeamais adults were 3.08 and 0.84 mg L⁻¹ air respectively. The LD₅₀ values (contact toxicity) of the crude essential oil and (Z)-ascaridole against S. zeamais adults were 2.12 and 0.86 µg g⁻¹ body weight respectively.
  
  
  CONCLUSIONS
  The findings suggested that the essential oil of Chenopodium ambrosioides and its main active constituent, (Z)-ascaridole, may be explored as a natural potential fumigant.
authors.affiliation: Department of Entomology, China Agricultural University, Beijing, China.
authors.forename: Sha Sha
authors.initials: SS
authors.lastname: Chu
authors.forename: Jin
authors.initials: J
authors.lastname: Feng Hu
authors.forename: Zhi Long
authors.initials: ZL
authors.lastname: Liu
mesh_terms: D000287:Administration, Topical; D000818:Animals; D027464:Chenopodium ambrosioides / Q000737:chemistry*; D005651:Fumigation / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry; D007306:Insecticides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D007928:Lethal Dose 50; D039821:Monoterpenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D009822:Oils, Volatile / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry*; D010938:Plant Oils / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D048889:Weevils / Q000187:drug effects* / Q000472:pathogenicity; D003313:Zea mays / Q000469:parasitology
chemical_list: D007306:Insecticides; D039821:Monoterpenes; D009822:Oils, Volatile; D010936:Plant Extracts; D010938:Plant Oils