Composition and antimicrobial activity of the essential oils of Helichrysum kraussii Sch. Bip. and H. rugulosum Less. from South Africa

The chemical compositions of the essential oils obtained from the aerial parts of Helichrysum kraussii and H. rugulosum were analysed by GC and GC–MS. From the 39 identified constituents, representing 85.1% and 92.9% of the two oils, respectively, β‐caryophyllene (30.7%, 12.6%), α‐pinene (12.1%,−), β‐caryophyllene oxide (−, 8.8%), cis ‐α‐bisabolene (−, 22.7%), β‐bisabolene (−, 4.7%) and α‐humulene (9.8%, −) were found to be the main components. Furthermore, the oils were tested against six Gram‐positive or ‐negative bacteria and three pathogenic fungi. It was found that oils from both plants, and especially that of H. rugulosum , exhibited interesting antibacterial activity.