Mode of action and pesticidal activity of the natural product dunnione and of some analogues.
This paper reports the investigation of the insecticidal and fungicidal activity of dunnione, a natural product obtained inadvertently as a by-product of a synthesis programme. Dunnione exhibits no insecticidal activity but has an unusually broad spectrum of antifungal activity. In vitro and in vivo (preventative) activities were comparable to those of several long-established fungicides (eg carbendazim). However, in whole-plant assays, its eradicant activity was unexpectedly low, probably due to poor dose-transfer from leaf surface to fungus. The level of residual activity appears to be influenced by the formulation. Finally, its potential as a lead structure was assessed, and several analogues synthesised which exhibited high activity in the in vitro assays. Mode-of-action studies revealed that dunnione exerts its action primarily through initiation of redox cycling. This contrasts to the activity of BTG 505, the biochemical/chemical precursor, which does not initiate redox cycling but instead exhibits both insecticidal and fungicidal activity by inhibiting mitochondrial Complex III.
Khambay
Bhupinder P S
BP
Division of Biological Chemistry, IACR-Rothamsted, Harpenden, Hertfordshire AL5 2JQ, UK. bhupinder.khambay@bbsrc.ac.uk
Batty
Duncan
D
Jewess
Philip J
PJ
Bateman
Geoffrey L
GL
Hollomon
Derek W
DW
D000818:Animals; D001681:Biological Assay; D001685:Biological Factors / Q000138:chemical synthesis / Q000633:toxicity*; D002247:Carbon Isotopes; D019069:Cell Respiration / Q000187:drug effects; D042967:Electron Transport Complex I; D014450:Electron Transport Complex III / Q000037:antagonists & inhibitors; D005658:Fungi / Q000187:drug effects; D005659:Fungicides, Industrial / Q000138:chemical synthesis / Q000633:toxicity*; D007300:Insect Control / Q000379:methods; D007313:Insecta / Q000187:drug effects*; D007306:Insecticides / Q000138:chemical synthesis / Q000633:toxicity; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009247:NADH, NADPH Oxidoreductases / Q000037:antagonists & inhibitors; D009285:Naphthoquinones / Q000138:chemical synthesis / Q000633:toxicity*; D010084:Oxidation-Reduction / Q000187:drug effects; D021281:Quantitative Structure-Activity Relationship
C474011:BTG 504; C474010:BTG 505; D001685:Biological Factors; D002247:Carbon Isotopes; D005659:Fungicides, Industrial; D007306:Insecticides; D009285:Naphthoquinones; C474009:dunnione; D009247:NADH, NADPH Oxidoreductases; D042967:Electron Transport Complex I; D014450:Electron Transport Complex III