Fumigant Toxicity of the Essential Oils of some African Plants against Anopheles Gambiae Sensu Stricto.
Loading...
Date
2005-03
Authors
Ndiege, I. O.
Omolo, M. O.
Okinyo, D.
Lwande, W.
Hassanali, Ahmed
Journal Title
Journal ISSN
Volume Title
Publisher
Phytomedicine
Abstract
The essential oils from 15 species of African plants selected by ethnobotanical considerations and field inspection (odour and presence of insects) were screened for fumigant toxicity to Anopheles gambiae s.s. in the laboratory. Essential oils from 6 species showed varying levels of toxicity, with Conyza newii (Compositae) and Plectranthus marruboides (Labiateae) being the most potent. Fifty compounds representing ∼74% of the essential oil of C. newii were identified by GC-MS and GC-coinjection (for available standards). The major and some of the minor constituents of the two oils were assayed at different doses. Two compounds, from C. newii, perillaldehyde and perillyl alcohol, exhibited higher fumigant toxicity (LD50=1.05×10−4 and 2.52×10−4 mg cm−3, respectively) than the parent oil (2.0×10−3 mg cm−3). GC-MS analysis of the essential oil of P. marruboides gave results similar to that previously reported. Interestingly, none of its components were active, suggesting that the insecticidal activity of the oil results from either some of the minor components or as a blend effect of some of the major constituents.
Description
Keywords
Conyza newii, Plenctranthus marruboides, Compositae, Labiateae, Anopheles gambiae, Fumigant toxicity, Essential oil composition, Perillaldehyde, Perillyl alcohol
Citation
Phytomedicine. 2005 Mar;12(3):241-6.