ANTIVIRAL PROPERTIES OF ESSENTIAL OILS

BY Arianna Staruch, ND, ACHS Academic Dean

Long before the development of antiviral medications, natural support options have been used to address influenza and the common cold. Essential oils are know to have antiviral activity, specifically the monoterpene constituents, such as alpha-terpinene, gamma-terpinene, alpha-pinene, p-cymene, terpinen-4-ol, alpha-terpineol, thymol, citral, and 1,8-cineole.  A number of essential oils, including eucalyptus (Eucalyptus globulus), lemon balm (Melissa officinalis), manuka (Leptospermum scoparium), peppermint (Mentha piperita), tea tree (Melaleuca alternifolia), and thyme (Thymus vulgaris) have been found to have antiviral activity against the herpes simplex virus type 1 (HSV-1) in vitro.123 

In addition, some essential oils have been tested for specific antiviral activity against the influenza virus. The essential oil of Houttuynia cordata (an Asian plant related to lizard’s tail) was found to have direct inhibitory activity against the influenza virus in vitro by interfering with the function of the viral envelope, which help viruses to enter host cells.4 However, there have not been any clinical trials yet with human subjects to see if these in vitro or animal studies will translate into effective treatment options as compared with antiviral medications.

One of the common occurrences with influenza is fever. Fever is a protective mechanism of the body to increase the activity of the immune cells. However, sometimes fever can be debilitating or even life threatening. Fevers of more than 103° should be addressed quickly with your healthcare provider. Radix bupleuri (bupleurum root) is widely used in traditional Chinese medicine to address fever, pain, and inflammation associated with influenza or the common cold. A recent study looked at preparing a nasal spray from the essential oil of this herb and tested it in animals for effectiveness. It did show promise as a fever reducer.5 However, many essential oils can be irritating to mucus membranes and should not be used undiluted or without first doing a skin patch test.

So how can you use essential oil in your everyday life to help reduce to risk of viral infection? Essential oils can be used in the home as antiviral cleaning products. A diffuser with any of the oils listed above, such as eucalyptus, lemon balm, or peppermint, may reduce the airborne viruses in a room. In addition, essential oils may be added to hand creams to help reduce the spread of viruses by contact. Of course, these should be used in addition to the common sense CDC recommendations to wash your hands frequently, cover your mouth and nose with your arm when you sneeze, and to stay home if you are sick. (You should see your primary care provider for a proper diagnosis if you think you may have the seasonal flu or the H1N1 flu, and follow their recommendations.) This fall may be a challenging time because there is the potential for many people to be sick with the flu at the same time, but we can use natural support options, such as essential oils, to keep us healthy.

References
1. Astani, A., Reichling, J., and Schnitzler, P. Comparative study on the antiviral activity of selected monoterpenes derived from essential oils. Phytother Res. 2009 Aug 3.
2. Reichling, J., Koch, C., Stahl-Biskup, E., Sojka, C., and Schnitzler, P.
Virucidal activity of a beta-triketone-rich essential oil of Leptospermum scoparium (manuka oil) against HSV-1 and HSV-2 in cell culture. Planta Med. 2005 Dec;71(12):1123-7.
3. Schnitzler, P., Schuhmacher, A., Astani, A., and Reichling, J. Melissa officinalis oil affects infectivity of enveloped herpesviruses. Phytomedicine. 2008 Sep;15(9):734-40.
4. Hayashi, K., Kamiya, M., Hayashi, T. Virucidal effects of the steam distillate from Houttuynia cordata and its components on HSV-1, influenza virus, and HIV. Planta Med. 1995 Jun;61(3):237-41.
5. Xie, Y., Lu, W., Cao, S., Jiang, X., Yin, M., and Tang, W. Preparation of bupleurum nasal spray and evaluation on its safety and efficacy. Chem Pharm Bull (Tokyo). 2006 Jan;54(1):48-53.