Dihydronepetalactones Deter Feeding Activity by Mosquitoes, Stable Flies, and Deer Ticks

• Published in: Journal of medical entomology Vol. 46; no. 4; pp. 832 - 840
• Main Authors: Feaster, John E, Scialdone, Mark A, Todd, Robin G, Gonzalez, Yamaira I, Foster, Joseph P, Hallahan, David L
• Format: Journal Article
• Language: English
• Published: England 01.07.2009
• Subjects: Aedes - drug effects; Aedes - physiology; Aedes aegypti; Animals; Anopheles - drug effects; Anopheles - physiology; Anopheles albimanus; antifeedants; antifeeding activity; botanical pesticides; Cyclopentanes - pharmacology; deet; diastereomers; dihydronepetalactones; disease vectors; duration; essential oils; Feeding Behavior - drug effects; Humans; hydrogenation; insect bites and stings; Insect Bites and Stings - prevention & control; Insect Control - methods; insect pests; insect repellents; Insect Repellents - pharmacology; insect vectors; Ixodes - drug effects; Ixodes - physiology; Ixodes scapularis; lactones; monoterpenoids; Muscidae - drug effects; Muscidae - physiology; Nepeta cataria; Pyrones - pharmacology; repellents; Stomoxys calcitrans
• ISSN: 0022-2585; 1938-2928
• DOI: 10.1603/033.046.0413

The essential oil of catmint, Nepeta cataria L., contains nepetalactones, that, on hydrogenation, yield the corresponding dihydronepetalactone (DHN) diastereomers. The DHN diastereomer (4R,4aR,7S,7aS)-4,7-dimethylhexahydrocyclopenta[c]pyran-l(3H)-one, DHN 1) was evaluated as mosquito repellent, as was the mixture of diastereomers {mostly (4S,4aR,7S,7aR)-4,7-dimethylhexahydrocyclopenta[c]pyran-1(3H)-one, DHN 2} present after hydrogenation of catmint oil itself. The repellency of these materials to Aedes aegypti L. and Anopheles albimanus Wiedemann mosquitoes was tested in vitro and found to be comparable to that obtained with the well-known insect repellent active ingredient N,N-diethyl-3-methylbenzamide (DEET). DHN 1 and DHN 2 also repelled the stable fly, Stomoxys calcitrans L., in this study. DHN 1, DHN 2, and p-menthane-3,8-diol (PMD), another natural monoterpenoid repellent, gave comparable levels of repellency against An. albimanus and S. calcitrans. Laboratory testing of DHN 1 and DHN 2 using human subjects with An. albimanus mosquitoes was carried out. Both DHN 1 and DHN 2 at 10% (wt:vol) conferred complete protection from bites for significant periods of time (3.5 and 5 h, respectively), with DHN2 conferring protection statistically equivalent to DEET. The DHN 1 and DHN 2 diastereomers were also efficaceous against black-legged tick (Ixodes scapularis Say) nymphs.