Chemical composition and biological activity of the volatiles of Anthemis melampodina and Pluchea dioscoridis.

The volatile fractions obtained by hydrodistillation of the fresh leaves of Anthemis melampodina and Pluchea dioscoridis were analysed by GC-MS technique. Of 38 components identified in the volatile oil of A. melampodina, santolinatriene was the major component (27.33%). The oil was characterized by a high percentage of monoterpene hydrocarbons (49.94%) while sesquiterpene hydrocarbons and oxygenated sesquiterpenes represented only 7.41% and 11.43% of the oil. 36 components were identified in the volatile oil of P. dioscoridis. Farnesol was the major component (16.50%) accompanied by a high percentage of sesquiterpene alcohols. Oxygenated sesquiterpenes (26.43%) and sesquiterpene hydrocarbons (39.43%) represented the main constituents in the oil. P. dioscoridis showed a marked mosquito larvicidal activity against Culex pipiens (LC(50) 71.86 ppm), while A. melampodina was moderately active (LC(50) 139.42 ppm).