title: Methyl palmitate, an acaricidal compound occurring in green walnut husks.
abstract: Walnut, Juglans regia L., is known for its insecticidal activities to a range of herbivores and microbes. Isolation and identification of bioactive compounds from walnut is a potential approach for the development of new pesticides. Laboratory experiments were carried out to investigate the acaricidal activities of green husk extracts of walnut. Bioassay-guided fractionation of petroleum-ether extracts of walnut led to the identification of a common plant-borne fatty acid ester, methyl palmitate (MP), which produced strong acaricidal activity (62.8% mortality) at 1 mg/ml at 24 h. The structure of MP was characterized with infrared spectrum and NMR, and the identification of MP confirmed using an authentic standard on high-performance liquid chromatography. Based on a slide dip bioassay, 10 mg/ml MP provided 97.9% mortality against adults of Tetranychus cinnabarinus (Boisduval) (Acari: Tetranychidae), whereas mortality against eggs was much lower (57.2%).
authors.affiliation: Beijing University of Agriculture, Beijing 102206, People's Republic of China.
authors.forename: Y N
authors.initials: YN
authors.lastname: Wang
authors.forename: H X
authors.initials: HX
authors.lastname: Wang
authors.forename: Z J
authors.initials: ZJ
authors.lastname: Shen
authors.forename: L L
authors.initials: LL
authors.lastname: Zhao
authors.forename: S R
authors.initials: SR
authors.lastname: Clarke
authors.forename: J H
authors.initials: JH
authors.lastname: Sun
authors.forename: Y Y
authors.initials: YY
authors.lastname: Du
authors.forename: G L
authors.initials: GL
authors.lastname: Shi
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D007306:Insecticides / Q000302:isolation & purification*; D031324:Juglans / Q000737:chemistry*; D010168:Palmitates / Q000302:isolation & purification*; D010936:Plant Extracts / Q000737:chemistry; D013055:Spectrophotometry, Infrared; D040102:Tetranychidae
chemical_list: D007306:Insecticides; D010168:Palmitates; D010936:Plant Extracts; C019012:methyl palmitate