Chemical composition and larvicidal activity of essential oil of Artemisia gilvescens against Anopheles anthropophagus

Artemisia gilvescens, a traditional Chinese medicinal plant, is chiefly distributed in the middle and lower reaches of the Yangtze River, China. Chemical composition of hydrodistilled essential oil from A. gilvescens was investigated by gas chromatography and mass spectroscopy (GC-MS), and larvicidal activity of the oil and its six main compounds against Anopheles anthropophagus was carried out by WHO method. In total, 56 compounds corresponding to 98.20 % of the total oil were identified and the major compounds identified were camphor (13.49 %), eucalyptol (12.13 %), terpine-4-ol (9.65 %), germacrene D (8.62 %), caryophyllene oxide (4.65 %), and caryophyllene (4.29 %). Essential oil induced 8, 46, 80, 85, 94, and 100 % larval mortality at the concentrations of 25, 50, 75, 100, 125, and 150 mg/l, and the LC₅₀ and LC₉₀ values were 49.95 and 97.36 mg/l, respectively. Among the six compounds, the most potent larvicidal compound was caryophyllene oxide and germacrene D, with LC₅₀ values of 49.46 and 49.81 mg/l and LC₉₀ values of 115.38 and 106.19 mg/l, respectively. Terpine-4-ol had LC₅₀ and LC₉₀ values of 76.70 and 139.42 mg/l followed by camphor which showed LC₅₀ and LC₉₀ values of 129.17 and 192.42 mg/l, respectively. The least potent among the six compounds were eucalyptol and caryophyllene, with and LC₅₀ value exceeding 200 mg/l. In general, it also shows a dose-dependent effect on mortality, with increasing concentrations of essential oil and compounds increasing mortality of the larvae. The essential oil of A. gilvescens and its several major compounds may have potential for use in control of A. anthropophagus.