Composition of the Essential Oil of Helichrysum forsskahlii (Gmel) Hilliard et Burt

Abstract The essential oil obtained by hydrodistillation of the aerial parts of Helichrysum forsskahlii, endemic to southern Saudi Arabia, was analyzed by GC/MS. Eighty-one compounds, representing more than 85.9% of the oil, were identified with selina-5,11-diene (45.3%), δ-3-carene (7.8%), 1,8-cineole (4.2%) and β-caryophyllene (4.9%) as main constituents. The major component, selina-5, 11-diene, being not previously isolated from natural sources, was isolated by column chromatography and its identity confirmed by 1 and 2D NMR spectral analysis. The oil showed only a very weak activity against Mycobacterium smegmatis, with no activity against Gram-positive and Gram-negative bacteria or Candida test organisms. Likewise, selina-5, 11-diene showed only a weak activity against M. intracellulare.