Immune-modifying and antimicrobial effects of eucalyptus oil and simple inhalation devices

Abstract

Eucalyptus oil (EO)and its major component, 1,8-cineole, have antimicrobial effects against many bacteria, including Mycobacterium tuberculosis and methicillin-resistant Staphylococcus aureus (MRSA), viruses, and fungi (including Candida). Surprisingly for an antimicrobial substance, there are also immune-stimulatory, anti-inflammatory, antioxidant, analgesic, and spasmolytic effects. Of the white blood cells, monocytes and macrophages are most affected, especially with increased phagocytic activity. Application by either vapor inhalation or oral route provides benefit for both purulent and non-purulent respiratory problems, such as bronchitis, asthma, and chronic obstructive pulmonary disease (COPD). There is a long history of folk usage with a good safety record. More recently, the biochemical details behind these effects have been clarified. Although other plant oils may be more microbiologically active, the safety of moderate doses of EO and its broad-spectrum antimicrobial action make it an attractive alternative to pharmaceuticals. EO has also been shown to offset the myelotoxicity of one chemotherapy agent. Whether this is a general attribute that does not decrease the benefit of chemotherapy remains to be determined. This article also provides instruction on how to assemble inexpensive devices for vapor inhalation. (Altern Med Rev 2010;15 (1):33-47)

Introduction

Eucalyptus oil (EO) has antibacterial, antiviral, and antifungal components and a long history of use against the effects of colds, influenza, other respiratory infections, rhinitis, and sinusitis.

Inhalation of the vapor is safe; historical usage employed the method of breathing the vapor over a bowl of hot water containing a few drops of EO with a towel-tent over the head. Readers are likely to have experience with eucalyptus oil via their parents, who may have applied Vicks VapoRub[R] to the chest area and even to the nose for respiratory difficulty or infection. It seems that Vicks VapoRub not only works through inhalation, but also through absorption into the tissues of the chest. (1,2)

Devices are now sold in pharmacies that allow one to inhale vapor, foregoing the bowl, towel, stove, and risk of a par-boiled face. These devices perhaps provide greater convenience than the bowl of hot water, but the rather expensive per-use pads required for the device contain little EO.

This article reviews the published data on the medicinal attributes, safety, and efficacy of eucalyptus oil. The article also describes a simple, low-cost home delivery system for the vapor and an easily constructed pocket inhaler. Included is limited information on activity of other plant oils with similar components.

Most of the references cited have been obtained from a PubMed search of eucalyptus oil cross--referenced with other subjects. Some of the references cited were not found in PubMed, but in bibliographies of other publications. A PubMed search for 1,8-cineole (Figure 1), the major component of most EO species and present in tea tree, rosemary, and other plant oils, lists 635 publications. References on EO as an antiparasitic or antiprotozoan, bug repellent, or insecticide are not covered in this discussion; use of EO to increase penetration of other agents through the skin is also not included.

Components of Eucalyptus Oil

The percentage of...