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Chemical Composition and Biological Activity of Essential Oils from Four Nepeta Species and Hybrids against Aedes aegypti (L.) (Diptera: Culicidae)

Abbas Ali, Nurhayat Tabanca, Betul Demirci, Eugene K. Blythe, K. Husnu Can Baser and Ikhlas A. Khan

National Center for Natural Products Research, The University of Mississippi, University, MS 38677 USA

Department of Pharmacognosy, Anadolu University, Faculty of Pharmacy, 26470 Eskisehir, Türkiye

Coastal Research and Extension Center, Mississippi State University, South Mississippi Branch Experiment Station, Poplarville, MS 39470 USA

Botany and Microbiology Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia

Department of Biomolecular Sciences, School of Pharmacy, The University of Mississippi, University, MS 38677 USA

Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh 11451

Abstract: Essential oils of four ornamental species and hybrids of Nepeta: N. racemosa Lam. hybrid ‘Select’, N. sibirica L., N. subsessilis Maxim, and N.×faassenii Bergmans ex Stearn ‘Dropmore were studied for their chemical composition, larvicidal and biting deterrent activity. Water-distilled essential oils from aerial parts of Nepeta species were analyzed by gas chromatography (GC-FID) and gas chromatography mass spectrometry (GC-MS). Nepeta racemosa hybrid ‘Select’ and N. ×faassenii ‘Dropmore’ essential oils were rich in 1,8-cineole whereas N. sibirica and N. subsessilis essential oils mainly consisted of sesquiterpenes: (Z)- b -farnesene, b -bisabolene, d -cadinene or b -caryophyllene, and caryophyllene oxide. Many Nepeta species essential oils are reported to be rich in nepetalactone isomers, but essential oils from these species contained either very low or no nepetalactone content. In biting deterrent bioassays, essential oils of these Nepeta species and hybrids at 100 µg/cm 2 showed activity similar to DEET at 25 nmol/cm 2 against Aedes aegypti, whereas this activity at the concentration of 10 µg/cm 2 was lower than DEET. All the essential oils showed weak larvicidal activity and mortalities were observed only at highest dose of 125 ppm against Ae. aegypti.

Keywords: Nepeta racemosa ; Nepeta sibirica; Nepeta subsessilis; Nepeta ×faassenii; essential oil; biting deterrent; larvicide; mosquito; catmint. © 2015 ACG Publications. All rights reserved.