The Activity of Cedar Leaf oil Vapor against Respiratory Viruses: Practical Applications

Respiratory viruses continue to cause frequent acute and chronic infections, for which few satisfactory treatments are available. Some essential oils possess antiviral properties, but these have usually been tested as liquids, which have limited applications. In this study the vapor of cedar leaf oil (CLO vapor) was evaluated for antiviral activity, in addition to its possible anti-inflammatory activity. The viruses tested, Influenza viruses, Rhinovirus, Adenovirus, and Herpes simplex viruses 1 and 2, in the form of dried films, were all inactivated by exposure to CLO vapor. In assays for influenza viral hemagglutinin (HA) the HA activity was inhibited by CLO vapor. Exposure of human lung epithelial cell monolayers to the vapor showed inhibition of rhinovirus virus-induced cytokine IL-6, but the cells themselves were not adversely affected by short exposure to the vapor. However the two major volatile components of CLO, thujone and  - pinene, did not show activity against influenza viral infectivity or hemagglutinin, indicating possible synergistic effects of the whole vapor. We conclude that CLO vapor has potential applications in the control of viral respiratory infections.