Composition and antimicrobial activity of the essential oils from flowers of Senecio othonnae, S. racemosus, and S. nemorensis

Abstract

The chemical composition of the essential oils of Senecio othonnae, S. racemosus, and S. nemorensis obtained by hydrodistillation of fresh flowers were analysed by GC-FID and GC-MS. A total of seventy-six compounds were identified, constituting over 83.1%, 97.7% and 86.8% of the total oil composition of the flowers of S. othonnae, S. racemosus, and S. nemorensis. The main components of the oils were caryophyllene oxide (18.6%), (E)-β-farnesene (21.6%), and γ-curcumene (42.8%), respectively. Sesquiterpene hydrocarbons were the main group of constituents of all three species, forming 34.6%, 73.2%, and 81.8% of the oils, respectively. The oils of S. othonnae, and S. nemorensis showed antimicrobial activity against Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, and Candida tropicalis, but that of S. racemosus was only active against Candida tropicalis.