|TABANCA, NURHAYAT - University Of Mississippi|
|AVONTO, CRISTINA - University Of Mississippi|
|WANG, MEI - University Of Mississippi|
|PARCHER, JON - University Of Mississippi|
|ALI, ABBAS - University Of Mississippi|
|DEMIRCI, BETUL - University Of Mississippi|
|RAMAN, VIJAYASANKAR - University Of Mississippi|
|KHAN, IKHLAS - University Of Mississippi|
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/22/2013
Publication Date: 11/22/2013
Citation: Tabanca, N., Avonto, C., Wang, M., Parcher, J.F., Ali, A., Demirci, B., Raman, V., Khan, I.A. 2013. Comparative investigation of Umbellularia californica and Laurus nobilis Leaf essential oils and identification of constituents active against Aedes aegypti. Journal of Agricultural and Food Chemistry. 61:12283-12291.
Interpretive Summary: Umbellularia californica (California Bay Laurel ) is a monotypic genus belong to Umbellularia (Lauraceae) and it is native to southwestern Oregon and northern California. Native Americans used it as spice, to repel fleas and to eliminate ground squirrels problems. Even though traditional use of the plant has a long history, the potential uses of U. californica as insecticide and repellent have yet to be scientifically proven. In the present study, an ethnopharmacological approach was used to select U. californica leaf essential oil for investigation of its mosquito activity against Aedes aegypti. The leaves of U. californica may be mistaken or used as a substitute for Mediterranean bay laurel (Laurus nobilis) on the market. The oil compositions between U. californica and L. nobilis along with their biting deterrent and larvicidal activity against Aedes aegypti were compared.
Technical Abstract: Umbellularia californica (California Bay Laurel) is a native species from California and its leaves are commonly used as spice and insect repellent. The leaves of U. californica may be mistaken or used as a substitute for Mediterranean bay laurel (Laurus nobilis) on the market. The essential oils from the leaves of both genera were analyzed by gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The monoterpene ketone umbellulone was found as the major compound (37%) in U. californica essential oil, whereas this monoterpene was not detected in Laurus nobilis essential oil. Identification of umbellulone was confirmed by isolation and NMR data. In the present study, an ethnopharmacological approach was used to select U. californica leaf essential oil for investigation of its mosquito activity against Aedes aegypti. Umbellularia californica oil showed biting deterrent activity and bioassay-guided fractionation was performed with this oil. Thymol showed the highest biting deterrent activity which was lower than DEET and followed by (-)-umbellulone, eucalyptol and (-)-'-terpineol. Umbellularia californica essential oil also showed good larvicidal activity against 1 day old Ae. aegypti larvae with an LD50 value of 52.6 ppm. Thymol showed the highest larvicidal activity with an LD50 value of 17.6 ppm followed by p-cymene, (-)-umbellulone and methyl eugenol. Laurus nobilis essential oil showed biting deterrent activity similar to solvent control, ethanol and no larvicidal activity. The present study clearly pointed out the diversity of the oil compositions between U. californica and L. nobilis along with their different in biting deterrent and larvicidal activity.