Fixed and volatile constituents of Acritopappus micropappus and their chemophenetics significance

Phytochemical investigation of the hexane extract of the aerial parts of Acritopappus micropappus (Asteraceae) led to the isolation of two sesquiterpenes (1 and 2), four triterpenes (3-6), two steroids (7 and 8) and one lignan (9). The essential oils of the aerial parts of A. micropappus collected at three different locations were obtained by hydrodistillation and analyzed by gas chromatography coupled with mass spectrometry allowing the identification of six monoterpenes (10-15), 24 sesquiterpenes (16-39), and one aliphatic ketone (40). This is the first report of compounds 1, 2, 9, 20, and 34 in the Asteraceae family, whereas this is the first report of compounds 38, 13, 15-17, 22, 24-27, 29-33, 35, 36, 38-40 in the genus Acritopappus. Compounds 10-12, 14, 18, 19, 21, 23, 28, and 37 have been described in other Acritopappus species, but this is the first report in A. micropappus. The chemophenetics significance of these compounds is described herein.