Despite advances in modern technologies,the healthcare industry is continuously challenged with the threat of microbialinfections. The overuse of antibiotics has further escalated this problem, resultingin the increasing emergence of antibiotic-resistant pathogens. Efforts todevelop new methods for controlling microbial infections are extremelyimportant. Accordingly, essential oils such as tea tree oil have emerged as novel,viable, and safe options for the treatment, and/or eradication of thesemicrobes.
Tea tree oil components are discussed in terms of current uses and futurepotential as antimicrobials. They have been around for thousands of years andused well before any modern medicine was around. The review also presents somesafety concerns to ensure safe and effective exploitation of essential oils in thefuture. INTRODUCTION Tea tree oil is a popular essential oil used mostly forits strong antimicrobial characteristics.
It is volatile as an essential oil, andit is sourced from an Australian plant called Melaleuca alternifolia. It is widely used to treat a number ofdifferent conditions. Tea treeoil (TTO) is most commonly associated with skin conditions such as acne, whichis caused by a bacterium known as Propionibacteriumacnes. Antibiotics are usually prescribed to treat this condition howeverthere are now antibiotic resistant strains present (Coates et al. 2002).
Tea Tree Oil first became known to the western world in around1732. It was discovered by Captain James Cook when he arrived in Australia. He discovereda spicy and refreshing tea from the leaves of the Melaleuca Alternifolia tree. It was from this that the plant becameknown as “tea tree”. The native Australians at the time used it to treat skininfections and wounds. When James Cook realised this he returned with a sampleof the plant and had a doctor test it for its healing properties.
The doctorconfirmed that it had a powerful antiseptic characteristic. Shortly after this,the use of TTO expanded, and it is now well-known worldwide as a non-synthetic antimicrobial(Halcon et al. 2003).Australia is the only country where the Melaleuca Alternifolia tree grows thereforethey must export it to other countries. Tea tree oil is made up of many different chemicalcomponents which give it its antiseptic powers.
The four main chemicalcomponents of tea tree oil would be as follows; Terpinen-4-ol, ?-Terpinene, ?-Terpineneand Terpinolene. Some other components include ?-Terpineol, ?-Pinene, Limoneneand ?-Cymene. There are approximately 98 different components which can bepresent in tea tree essential oil. The concentrations of these components varyfrom oil to oil. However there are certain standards put in place by theAustralian and International Standards Organizations to ensure quality of oili.e. a minimum and maximum concentration range for each component (Halcon etal.
2003). Tea tree oil can come in six different chemical combinations. Thereis a terpinen-4-ol type which is the one that is commercially produced, aterpinolene type, and four 1, 8-cineole types. As I’ve already mentioned, the natural antimicrobialeffects of tea tree oil are well recognized worldwide.
In recent decadesnatural and alternative remedies are becoming more and more popular. Thisreview compiles current developments in the acceptance of the antimicrobial powerof TTO and its components, as well as clinical efficiency. Specific mechanismsof antimicrobial action are reviewed and analysed, mainly with regards to skinbacteria to see if it could be used to replace traditional treatment methods ofantibiotics and harsh chemicals. MICROBES TTO shows antimicrobial action against a large range ofGram-positive and Gram-negative bacteria, yeasts and fungi (Kulik et al.2000). Howeverit usually is more active toGram-positive than to Gram-negative bacteria. The microbes that will be focusedon in this review are two gram positive microbes that affect the skin, Propionibacterium acnes andmethicillin resistant Staphylococcus aureus (MRSA) .
We will also look at the fungus athlete’s foot.Tea-tree oil is a popular component of skin preparations,and a number of its suggested uses imply an anti-microbial effect (Drury 1991).Tea-tree oil is recommended for the treatment of acne vulgaris. A study comparinga tea-tree oil gel to benzoyl peroxide lotion demonstrated the efficacy of theoil for treating this condition (Bassett et al.
1990). Propionibacterium acnesand coagulase-negative staphylococci have been implicated in the pathogenesis ofacne vulgaris (Shanson 1989), and it is possible that the oil works byeradicating these microorganisms from acne lesions. Propionibacterium acnes (P.acnes)colonize the skin and hair follicles. They are oxygen-tolerant, anaerobicbacteria that prefer to grow in low oxygen environments. They can developsticky lumps known as biofilms that help them to attach to surfaces and adjusttheir surroundings(http://thescienceofacne.com/what-is-propionibacterium-acnes/). In manysituations, bacterial biofilms have been proven to add to long term infections,and could help with the perseverance of P.
acnes infection in some individuals. As they are gram positive microbes theyhave bulky cell walls that aid with shielding them from their surroundings. Stillthese thick cell walls let hydrophobic particles pierce the cells without anydifficulty and move through the cell wall and inside the cytoplasm. Phenolic compoundswork this way and they are present in TTO, showing antimicrobial action againstGram-positive bacteria such as P.acnes (Nazzaroet al. 2013).
There are lots of other gram-positive bacteria that createinfections, such as MRSA. MRSA is a major cause of hospital infections and isbecoming increasingly difficult to combat as is it becoming resistant to allcurrent classes of antibiotics. Approximately 30% of burn wounds becomecolonized by MRSA in hospitals. Alternative therapies are being sought for thetreatment of MRSA and essential oils are of particular interest. TTO is provento be effective in treating this antibiotic resistant strain of Staphylococcus; however there areconcerns over its toxicity.
Even though essential oils are well known for beingantimicrobial, they are very rarely used by medical professionals. This ismainly because of lack of scientific evidence regarding efficacy. Additionallycommon medical care is extremely extensively accessible.
Edwards-Jones et al. 2004conducted a study trying to prove the efficacy of essential oils asantimicrobial agents. The five oils used in the experiment that was carried outwere tea tree, lavender, geranium, patchouli and citricidal. TTO had thehighest clearing zone when placed in direct contact with two different strainsof Staphylococcus aureus one beingthe methicillin resistant strain. Essential oils clearly work, so why aren’tthey being used to treat these bacteria? There is great potential for the use ofessential oils as natural antibiotics to control infections, especiallyinfections of the skin and to control antibiotic resistant strains of bacteria.
If there is no research done into new antibiotics, by the year 2050 a personwill die every three seconds from a bacterial infection (WHO). Seen as no newantibiotics are being discovered it is time to start looking at naturalalternatives and for funding to be put into researching essential oils in moredetail. As well as being antibacterial, TTO is also known for itsantifungal properties. TTO is well known to be effective in controlling thefungi that make up athletes foot. Athlete’s foot is generatedfrom Tinea pedis. It is a fungaldisease that for the most part starts among the toes.
It is often found inpeople whose feet have come to be really moist from perspiration while enclosedinside tightfitting shoes. It is infectious and can be disseminated throughinfected floors, towels or clothing. In a 1972 study done on various footproblems, Dr. Walker used tea tree oil in three different formulas to trycombating these problems. To start was unmixed oil, secondly was a mixture of 40%oil with 10% isopropyl alcohol.
This was known as Melasol. Third was 8% oilwith lanolin and chlorophyll and this was in ointment form. 60 people took partin the experiment. 40 took Melasol, 20 used the ointment and 8 applied the unmixedoil. The medical care changed from three weeks to four years. Of 68 patients,58 got alleviation from their foot ailments over a time frame of 6 years. Thereare four if not more various fungal diseases associated with athlete’s foot andeach of these show sensitivity to TTO.
Conventional treatments for fungal disease of the nails canbe; debridement which is removing alien materials and impaired tissue, andtopical treatment. This review evaluated the effectiveness of topical treatmentsof 1% clotrimazole solution in comparison with 100% TTO for treating of Tinea unguium which is a fungalinfection of the toenail. In a 6 monthdouble-blind, multicentre, randomised, controlled trial of 117 people witha Tinea unguiuminfection, patients got twice-dailytreatments of either 1% clotrimazole (CL) solution, which is topical antifungaldrug medication, or 100% (TTO). Debridement and clinical evaluation were carriedout at 0, 1, 3 and 6 months.
Samples were taken at 0 and 6 months. After 6months, the both factions were compared based on culture cure (CL=11%,TTO=18%). Three months on, almost half of both factions stated that they hadpersistent positive progress. The conclusion was, even though all ongoing treatmentshave high reoccurring percentages, using a topical application along withdebridement is a good treatment to start with.
Topical treatment, with regardsto the previous two concoctions, provides benefit in how the nail looks and anysymptoms associated with it, while oral treatment has the limitation of expenseand possible severe negative effects. This experiment supported the requirementto use a strong (in this case 100%) concentration of TTO to achieve improved short-termand long-term efficiency. In children and people with sensitive skin, a 70%solution may be superior. EVIDENCE In Vitro A study done byWalton et al in 2004 attempted to show the In Vitro Sensitivity of Sarcoptes scabiei var hominis toTerpinen-4-ol. The experiment went as follows. The parts of TTO known as; terpinen-4-ol,terpineol, and 1,8-cineole were utilized in vitro at concentrations equal tothose in 5% TTO.Terpinen-4-ol makes up 42% of TTO and was utuilzed at aconcentration of 2.1%, terpineol makes up 3% of TTO and was utilized at aconcentration of 0.
15%, and 1,8- cineole makes up 2% of TTO and was utilized ata concentration of 0.1%.Also, mites were shown to all 3 parts of TTO in acombined mix and to 5% TTO directly also.
An ivermectin solution of 100 µg/gwas also used for comparison as well as Emulsifying Ointment. The 5% TTO and active component terpinen-4-olwere effective in reducing mite survival times. Mathematically relevant dissimilarity’sin mite survival graphs were noticed for 5% TTO, terpinen-4-ol, and ivermectincompared to the control which was Emulsifying Ointment. Variability wasobserved in survival rates amongst each part of TTO.
85%of the mites haddeceased after 1 hour when shown to 2.1% terpinen-4-ol.