title: Insecticidal 2-hydroxy-3-alkyl-1,4-naphthoquinones: correlation of inhibition of ubiquinol cytochrome c oxidoreductase (complex III) with insecticidal activity.
abstract: The insecticidal and in vitro activities of four homologous series of 2-hydroxy and acetoxy-3-substituted-1,4-naphthoquinones have been measured and correlated with their (Log) octanol/water partition coefficients (Log Ko/w). In vitro activity against mitochondrial complex III was only exhibited by 2-hydroxy-3-alkyl-1,4-naphthoquinones, indicating that the 2-acetoxy compounds act as proinsecticides. Good correlation was observed between in vivo activity against the two-spotted spider mite, Tetranychus urticae and inhibition of complex III isolated from blowfly flight muscle. Both hydroxy and acetoxy analogues of individual compounds exhibited similar levels of in vivo activity with optimum activity for analogues with Log Ko/w values of 7-8. In contrast, the acetoxy derivatives showed superior in vivo activity against the tobacco whitefly, Bemisia tabaci. Complex III isolated from whitefly was optimally inhibited by hydroxy analogues with lower Log Ko/w values (6.0-6.5) and was also more sensitive than the blowfly enzyme to all the compounds tested.
authors.affiliation: Department of Biological and Ecological Chemistry, IACR-Rothamsted, Harpenden, Hertfordshire AL5 2JQ, UK. philip.jewess@bbsrc.ac.uk
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Jewess
authors.forename: Keith
authors.initials: K
authors.lastname: Chamberlain
authors.forename: Adrian B
authors.initials: AB
authors.lastname: Boogaard
authors.forename: Alan L
authors.initials: AL
authors.lastname: Devonshire
authors.forename: Bhupinder P S
authors.initials: BP
authors.lastname: Khambay
mesh_terms: D000465:Algorithms; D000818:Animals; D001681:Biological Assay; D014450:Electron Transport Complex III / Q000037:antagonists & inhibitors*; D006430:Hemiptera / Q000187:drug effects; D007300:Insect Control / Q000379:methods; D007306:Insecticides / Q000737:chemistry / Q000633:toxicity*; D008925:Mites / Q000187:drug effects; D008931:Mitochondria, Muscle / Q000187:drug effects / Q000201:enzymology; D009285:Naphthoquinones / Q000737:chemistry / Q000633:toxicity*; D021281:Quantitative Structure-Activity Relationship; D013384:Succinate Cytochrome c Oxidoreductase / Q000037:antagonists & inhibitors
chemical_list: D007306:Insecticides; D009285:Naphthoquinones; D013384:Succinate Cytochrome c Oxidoreductase; D014450:Electron Transport Complex III