Evaluation of mosquitocidal activity of essential oil and sesquiterpenes from leaves of Chloroxylon swietenia DC.
Growing awareness in using ecofriendly and biologically compatible phytoconstituents as natural insecticides and repellents for the safety of life and ecological balance led to conscientious efforts by scientists all over the world to search for alternative sources of plant derivatives for effective use as mosquitocides. Encouraged by this, the essential oil and the sesquiterpenes isolated from the leaves of Chloroxylon swietenia DC. were screened for mosquitocidal activity by fumigant toxicity against three mosquito species, Anopheles gambiae, Culex quinquefasciatus and Aedes aegypti. The essential oil had pronounced mosquitocidal activity with LD50 of 1.0, 1.2 and 1.7 x 10(-3) mg/cm(-3), respectively, for the three vector species. Furthermore, the major sesquiterpenes were tested at different doses, which again showed varying levels of toxicity. However, germacrene D performed better and proved to be the potential candidate with LD50 values of 1.8-2.8 x 10(-3) mg/cm(-3) followed by pregeijerene and geijerene. Nevertheless, the oil and the isolated compounds were particularly active against A. gambiae. The essential oil from the leaves was obtained by hydrodistillation, and the chemical composition was determined by GC and GC-MS. The main compounds identified were limonene, germacrene D, geijerene, pregeijerene, trans-beta-ocimene and methyl eugenol. The present study indicates that the oil and the isolated compounds of C. swietenia displayed remarkable mosquitocidal activity suggesting that the method could be extended for future field trials in various mosquito control programmes, and the results are compared with synthetic insecticides.
Kiran
S Ravi
SR
Department of Botany, Osmania University, Hyderabad, 500007, India.
Devi
P Sita
PS
D000330:Aedes / Q000187:drug effects; D000818:Animals; D000852:Anopheles / Q000187:drug effects; D003465:Culex / Q000187:drug effects; D009033:Culicidae / Q000187:drug effects*; D008401:Gas Chromatography-Mass Spectrometry; D007306:Insecticides / Q000494:pharmacology*; D007928:Lethal Dose 50; D009032:Mosquito Control; D009822:Oils, Volatile / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D027821:Rutaceae / Q000737:chemistry*; D012717:Sesquiterpenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*
D007306:Insecticides; D009822:Oils, Volatile; D010936:Plant Extracts; D012717:Sesquiterpenes