Brantley Grimball1, Lucas Veillon1,2,3, Tara Calhoun1, Frank R Fronczek4, Emily Arceneaux1, Roger A Laine1,4. 1. Department of Biological Sciences, Louisiana State University and A&M College, Baton Rouge, LA, USA. 2. Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Pharmaceutical University, Sendai, Japan. 3. Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA. 4. Department of Chemistry, Louisiana State University and A&M College, Baton Rouge, LA, USA.
Abstract
BACKGROUND: In experiments with Formosan subterranean termites (Coptotermes formosanus Shirakii), myo-inositol-2-monophosphate as the dicyclohexylammonium salt was tested among other sugar derivatives, and was found to be toxic to C. formosanus when added to a moistened filter paper food source in plastic Petri dishes. RESULTS: Curiously, over a nine-day period, the moniliform (beaded) antenna of C. formosanus deteriorated in a stepwise fashion with the most distal pseudosegment (bead) turning brown and falling off, followed by the penultimate pseudosegment, sequentially, until 7-9 days when only a stub of the antenna remained. Termites became increasingly moribund with the loss of antennae, and quit normal behavior including consuming cellulose food, and died. sn-Glycerol-3-phosphate as the dicyclohexylammonium salt also gave the same results. Dicyclohexylammonium hydrogen phosphate and monocyclohexylammonium dihydrogen phosphate were synthesized, to find a low-cost form for application to baits, both of which also showed similar toxicity. In a trial with Fibonacci series dilutions of neat cyclohexylamine, the antenna-affecting activity became apparent in the LD30 (14 days) to LD70 range of concentrations. At the higher concentrations, darkening of the most distal parts of leg extremities was noticed. CONCLUSION: Cyclohexylamine appears to be a novel termiticide with a previously unreported mechanism of toxicity. Its hydrogen phosphate salts retain the toxic effect and are inexpensive and easily synthesized.
BACKGROUND: In experiments with Formosan subterranean termites (Coptotermes formosanus Shirakii), myo-inositol-2-monophosphate as the dicyclohexylammonium salt was tested among other sugar derivatives, and was found to be toxic to C. formosanus when added to a moistened filter paper food source in plastic Petri dishes. RESULTS: Curiously, over a nine-day period, the moniliform (beaded) antenna of C. formosanus deteriorated in a stepwise fashion with the most distal pseudosegment (bead) turning brown and falling off, followed by the penultimate pseudosegment, sequentially, until 7-9 days when only a stub of the antenna remained. Termites became increasingly moribund with the loss of antennae, and quit normal behavior including consuming cellulose food, and died. sn-Glycerol-3-phosphate as the dicyclohexylammonium salt also gave the same results. Dicyclohexylammonium hydrogen phosphate and monocyclohexylammonium dihydrogen phosphate were synthesized, to find a low-cost form for application to baits, both of which also showed similar toxicity. In a trial with Fibonacci series dilutions of neat cyclohexylamine, the antenna-affecting activity became apparent in the LD30 (14 days) to LD70 range of concentrations. At the higher concentrations, darkening of the most distal parts of leg extremities was noticed. CONCLUSION:Cyclohexylamine appears to be a novel termiticide with a previously unreported mechanism of toxicity. Its hydrogen phosphate salts retain the toxic effect and are inexpensive and easily synthesized.