Melaleuca alternifolia is also known as tea tree, and the leaves of this native Australian tree can be treated to produce the popular extract tea tree oil. The oil comes from the leaves of Melaleuca alternifolia, and the process used to extract the essential oil from the leaves is steam distillation. While the leaves were used for hundreds of years for medicinal purposes by the native inhabitants of Australia, the wider acknowledgment of tea tree oil as a medicinal substance didn't occur until after 1922, when Australian chemist Arthur Penfold published a medical paper confirming the antibacterial and antifungal properties of the oil.
The antiseptic, germicidal properties of Meleleuca alternifolia oil are what the substance is best known and most used for. The oil is mainly composed of substances known as terpene hydrocarbons, which are volatile hydrocarbons. One of the most potent antimicrobial terpene hydrocarbons found in Meleleuca alternifolia oil is terpinen-4-ol, which is particularly effective at relieving the reddened, swollen tissue that comes with localized monocyte activity after a burn, bruise or cut.
In regards to the antibacterial functions of Meleleuca alternifolia oil, the terpene hydrocarbons present in the oil destroy bacteria by penetrating their membranes and disrupting their vital functions. The antifungal characteristics of Meleleuca alternifolia oil work much in the same manner. The terpene hydrocarbons in the oil have been found to be capable of penetrating the cell walls of fungi such as C. albicans, at which point the terpene hydrocarbons alter the structure and functioning of the invasive cells to the point of destruction. This is the mechanism behind Meleleuca alternafolia's ability to kill bacteria and fungi, making it a common and effective over-the-counter treatment for cuts, burns, fungal infections of the nails and skin, vaginal infections and mild acne. It is also effective in an antibacterial capacity when a mixture consisting of 5% Meleleuca alternafolia oil and water is used as an antibacterial hand wash in hospital and health care settings.
Meleleuca alternafolia oil is commonly applied to the skin for treatment of skin lesions and infections, though some users have reported sensitivity to the oil which resulted in allergic contact dermatitis. This irritation is temporary, and disappears within hours after the initial application. While it is generally not recommended for oral use, and is definitely not to be swallowed under any circumstances, studies have been conducted regarding the efficacy of Meleleuca alternafolia oil as a dental antibacterial wash. Conducted with 40 volunteers over seven days using a 0.2% strength solution, the studies concluded that while the oil had no effect whatsoever on plaque reduction, there was a significant reduction of oral bacteria and mutans streptococci. Even more interesting was the lasting effect of the oil on oral bacteria. Study participants were found to have reduced levels of oral bacteria for up to two weeks after cessation of the treatment. Though these studies show that Meleleuca alternafolia oil may be excellent at fighting gum infections such as gingivitis, along with the chronic halitosis that can come with these infections, it is still important to discuss the usage of Meleleuca alternafolia oil as a mouthwash with your dentist before using it for this purpose.