Terpenes and phototoxic compounds from the inflorescence of Simsia amplexicaulis (Cav.) Pers. (Asteracerae)

From the inflorescence of Simsia amplexicaulis (Cav.) Pers. two triterpenes, two diterpenes, a diacetilene and its acetate were isolated.The chromatographic profiles of the extracts (root, aerial parts and inflorescence) of this species and those of Encelia californica Nutt. were compared. Intergeneric differences were observed in the three parts of the plants; the S. amplexicaulis profiles showed an intraspecific difference which was absent in E. californica.