title: Acaricidal activity of four fractions and octadecanoic acid-tetrahydrofuran-3,4-diyl ester isolated from chloroform extracts of neem (Azadirachta indica) oil against Sarcoptes scabiei var. cuniculi larvae in vitro.
abstract: Four fractions obtained from chloroform extracts of neem (Azadirachta indica) oil by column chromatography were investigated for acaricidal activity against Sarcoptes scabiei var. cuniculi larvae in vitro. Octadecanoic acid-tetrahydrofuran-3,4-diyl ester was isolated from an active fraction of the chloroform extract and its toxicity against S. scabiei larvae was tested in vitro. A complementary log-log model was used to analyse the toxicity data. Activity was found in the third fraction, with 100% corrected mortality after 4.5 h of exposure at a concentration of 200 mg ml(-1). This fraction was repeatedly re-crystallised in acetone to yield a white amorphous powder, identified as octadecanoic acid-tetrahydrofuran-3,4-diyl ester, with a median lethal concentration (LC(50)) of 0.1 mg ml(-1) at 24 h post-treatment. The median lethal time (LT(50)) for this compound was 15.3 h at a concentration of 7.5 mg ml(-1).
authors.affiliation: College of Animal Medicine, Sichuan Agricultural University, Ya'an, 625014, PR China.
authors.forename: Yong-Hua
authors.initials: YH
authors.lastname: Du
authors.forename: Jin-Liang
authors.initials: JL
authors.lastname: Li
authors.forename: Ren-Yong
authors.initials: RY
authors.lastname: Jia
authors.forename: Zhong-Qiong
authors.initials: ZQ
authors.lastname: Yin
authors.forename: Xu-Ting
authors.initials: XT
authors.lastname: Li
authors.forename: Cheng
authors.initials: C
authors.lastname: Lv
authors.forename: Gang
authors.initials: G
authors.lastname: Ye
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Yu-Qun
authors.initials: YQ
authors.lastname: Zhang
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D005989:Glycerides / Q000737:chemistry*; D007306:Insecticides / Q000737:chemistry* / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects; D015394:Molecular Structure; D012520:Sarcoptes scabiei / Q000187:drug effects*; D013229:Stearic Acids / Q000737:chemistry* / Q000494:pharmacology*; D013729:Terpenes / Q000737:chemistry*
chemical_list: D005989:Glycerides; D007306:Insecticides; D013229:Stearic Acids; D013729:Terpenes; C543690:octadecanoic acid-tetrahydrofuran-3,4-diyl ester; C002443:neem oil