A recent study has suggested that tea tree oil can kill mouse mesothelioma cells in vitro. This indicates its potential usefulness in human mesothelioma, but more research is needed.
Tea tree oil comes from the leaves of Melaleuca alternifolia, a tree in the myrtle family that is found in Australia. The tree oil has been traditionally used as a topical anti-fungal and antibiotic. Laboratory studies have demonstrated that the compound that is most likely responsible for the oil’s antiseptic properties is called “terpinen-4-ol.”
In this study, researchers at the School of Biomedical, Biomolecular and Chemical Sciences at The University of Western Australia examined the in vitro anticancer activity of Melaleuca alternifolia (tea tree) oil and terpinen-4-ol. They tested the substances against an aggressive mouse mesothelioma tumor cell line and one for melanoma.
The researchers discovered that tree tea oil and terpinen-4-ol “significantly inhibited the growth of two murine tumor cell lines in a dose and time-dependent manner.” This meant that more mesothelioma and melanoma tumor cells died when the researchers introduced more tree oil and terpinen-4-ol. The researchers identified at least three mechanisms at work. First, tree oil and terpinen-4-ol elicited G1 cell cycle arrest – the compounds stopped the cancer cells from multiplying. The compounds also induced necrotic cell death and low level apoptotic cell death in both cell lines.
Necrosis is the premature death of cells caused by external factors, such as infection, toxins, or trauma. In contrast, apoptosis is a naturally occurring cause of cellular death. Apparently, both mechanisms were at work when the tea tree oil and terpinen-4-ol were introduced into the mesothelioma and melanoma cell lines.
The researchers also discovered that doses of the compounds that could kill the tumor cells were “significantly less efficacious” against non-tumor fibroblast cells. In other words, the compounds had a tendency to leave healthy cells intact.
The researchers concluded that their results demonstrate the potential anticancer activity of tea tree oil and terpinen-4-ol and that more research was needed.
If you are interested in using tea tree oil and/or terpinen-4-ol you should work with a licensed clinician. Please note that tea tree oil should not be used orally because there are reports of toxicity after consuming it by mouth. Also, when applied to the skin, tea tree oil is reported to be mildly irritating and has been associated with the development of allergic contact dermatitis in some people.
Greay SJ, et al., Induction of necrosis and cell cycle arrest in murine cancer cell lines by Melaleuca alternifolia (tea tree) oil and terpinen-4-ol. Cancer Chemother Pharmacol. 2009 Aug 13.