Chemical composition and larvicidal activity of leaf essential oil from Clausena anisata (Willd.) Hook. f. ex Benth (Rutaceae) against three mosquito species

ObjectiveTo determine the mosquito larvicidal activity of leaf essential oil and their chemical constituents from Clausena anisata(C. anisata) (Willd.) Hook. f. ex Benth. against Culex quinquefasciatus, Aedes aegypti and Anopheles Stephensi.MethodsEssential oil was obtained by hydro-distillation and the chemical composition of the leaf essential oil was analyzed using gas chromatography-mass spectrometry. The mosquitoes were reared in the vector control laboratory and twenty late III instar larvae of three mosquito species were exposed to based on the wide range and narrow range tests, essential oil was tested at 50, 100, 150, 200 and 250 ppm and each compound was tested at various concentration (5-75 ppm) and were assayed in the laboratory by using the protocol of WHO 2005; the 24 h LC50 values of the C. anisata leaf essential oil and their major compounds were determined following Probit analysis.ResultsThe oil contained were mainly β-pinene (32.8%), sabinene (28.3%), germacrene-D (12.7%), estragole (6.4%) and linalool (5.9%). The essential oil from the leaves of C. anisata exhibited significant larvicidal activity, with 24 h LC50 values of 140.96, 130.19 and 119.59 ppm, respectively. The five pure constituents extracted from the C. anisata leaf essential oil were also tested individually against three mosquito larvae. The LC50 values of β-pinene, sabinene, germacrene-D, estragole and linalool appeared to be most effective against Anopheles stephensi (LC50–23.17, 19.67, 16.95, 11.01, 35.17 ppm) followed by Aedes aegypti (LC50–27.69, 21.20, 18.76, 12.70, 38.64 ppm) and Culex quinquefasciatus (LC50–32.23, 25.01, 21.28, 14.01, 42.28).ConclusionThe essential oil of C. anisata contains five major compounds and has remarkable larvicidal properties, which may be considered as a potent source for the production of natural larvicides.