title: Insecticidal activity of deoxypodophyllotoxin, isolated from Juniperus sabina L, and related lignans against larvae of Pieris rapae L.
abstract: In the course of screening for naturally occurring insecticides from plants from the northwestern part of China, a petroleum ether extract of Juniperus sabina L was found to show insecticidal activity against fifth-instar larvae of Pieris rapae L. From the extract, an insecticidal compound was isolated by bioassay-guided fractionation. The compound was identified as deoxypodophyllotoxin (1) by comparison of its spectroscopic characteristics with literature data. In bioassays, 1 showed antifeedant activity against fifth-instar larvae of P rapae at 0.05-1.00 g litre(-1) and its AFC50 (concentration for 50% antifeedant activity) values at 12 and 48h were 0.170 and 0.060 g litre(-1), respectively. In that concentration range, all treated insects died within 48 h after treatment and compound 1 showed delayed insecticidal activity. At 0.015-0.100 g litre(-1), 1 showed insecticidal activity, with an LC50 of 0.020 g litre(-1). The related compound deoxypicropodophyllotoxin (2), however, showed lower antifeedant and insecticidal activities than 1 in bioassay. This indicated that the trans-lactone ring is an important moiety for enhancing activity in these compounds. Comparison of the insecticidal activities of 1 and another related compound, podophyllotoxin (3), suggested that varying the substituent at C-4 is an exciting possibility for synthesizing more potent analogues.
authors.affiliation: Department of Neurotoxicology, Applied Institute of Toxicology, Nanjing Medical University, Nanjing 210029, China. gaorong@njmu.edu.cn
authors.forename: Rong
authors.initials: R
authors.lastname: Gao
authors.forename: Congfen
authors.initials: C
authors.lastname: Gao
authors.forename: Xuan
authors.initials: X
authors.lastname: Tian
authors.forename: Xiangyang
authors.initials: X
authors.lastname: Yu
authors.forename: Xudong
authors.initials: X
authors.lastname: Di
authors.forename: Hang
authors.initials: H
authors.lastname: Xiao
authors.forename: Xing
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001681:Biological Assay; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal; D007306:Insecticides / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D018653:Juniperus / Q000737:chemistry*; D007814:Larva; D007915:Lepidoptera / Q000187:drug effects*; D007928:Lethal Dose 50; D011034:Podophyllotoxin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D013057:Spectrum Analysis / Q000379:methods
chemical_list: D004365:Drugs, Chinese Herbal; D007306:Insecticides; C014451:deoxypodophyllotoxin; D011034:Podophyllotoxin