Essential Oil of Ageratum conyzoides.

The essential oil of AGERATUM CONYZOIDES leaves was analysed by means of GC-MS and associated procedures. Fifty-one constituents - 13 monoterpenoid hydrocarbons (5.0%), 7 oxygenated monoterpenoids (1.4%), 16 sesquiterpenoid hydrocarbons (4.3%), 4 oxygenated sesquiterpenoids (0.8%), 3 phenylpropanoids and benzenoids (2.33%), 6 chromenes (85.2%), and 2 chromans (0.9%) - were identified. Only six of these components have been previously found in AGERATUM essential oil. The natural occurrence of the two chromans:6-acetyl-2,2-dimethyl-3,4-dihydro-chromene and its 7-methoxy derivative is being reported for the first time. The chemotaxonomic significance of the results is discussed.