茶樹精油應用於痤瘡治療之功效與安全性評估
Safety and efficacy evaluation of tea tree oil for acne
中文摘要
精油普遍用於化妝品及保養品，其中又以茶樹精油為廣泛用於芳香療法的精油之一。其源自於澳 洲茶樹具有抑制微生物、消炎作用，但是在高濃度時會引起皮膚刺激作用，因此本研究將探討茶 樹精油的安全、有效劑量及主要成分中導致皮膚刺激反應之相關性。以實證醫學方式搜尋茶樹精 油之臨床試驗文獻不多，且 Jadad 評值偏低，因此將進行後續基礎實驗。
首先取蒸餾萃取茶樹精油 (天然精油)，及市售品以氣相層析質譜儀檢測其主要成分，其品質均 符合 ISO 4730 之成分規範。繼而進行抑制金黃色葡萄球菌活性及皮膚局部使用之安全性探討。
12 個標準品、天然精油及市售品檢測抑制金黃色葡萄球菌活性。結果顯示：以 terpinolene (MIC 6.25%, MBC 100%)、α-terpinene (MIC 6.25%, MBC 25%)及 α-terpineol (MIC 10%, MBC 40%)之抗菌效果最佳。再以主要抗菌之成分調配人工配方精油，抗菌作用提高，且較天 然精油強，但仍不及某廠商市售品之效果。
皮膚接觸毒性檢測，是利用 neomycin 建立皮膚刺激反應標準。天然茶樹精油及主要毒性成分 1,8-cineole 與活性成分 terpinen-4-ol 檢測結果顯示：天然茶樹精油 2%以上即產生顯著之 皮膚刺激毒性，而 1,8-cineole 及 terpinen-4-ol 則無顯著毒性。另外，連續 28 天塗抹 2%茶 樹精油於 Wistar 大鼠皮膚，觀察血清中 GOT、GPT、BUN 及 creatinine 之變化，相對於溶媒 組，其無顯著影響肝腎功能。
綜合實證醫學及基礎研究對於茶樹精油應用於痤瘡治療之功效與安全性之探討結果：茶樹精油確 實能有效抑制金黃色葡萄球菌，並有抗發炎之機轉，而達成治療痤瘡之效果；且若低濃度塗抹局 部皮膚使用而非口服，亦不會對身體造成毒性。
英文摘要
Tea tree oil (TTO) is one of the essential oils that are popularly used in cosmetics and mending agents. TTO, the essential oil of Melaleuca alternifolia, is used in
aromatherapy and has been investigated as antimicrobial and anti-inflammatory agents. However, TTOs can cause skin irritation at high concentrations. In this study, we explored the safety and efficient dosage of TTO and investigated the mechanism of TTO-induced skin irritation between with its components. The clinical trial literatures with randomized and double blinding design were very rare and Jadad score very low. Therefore, we executed following animal experimental research.
Tea tree oils were extracted by hydrodistillation and five brands commercial TTOs were purchased in Taiwan market. All compositions fit with International Standard 4730 guideline for TTO. In the followings, we established anti-Staphylococcal activity and safety evaluation for skin irritations of TTOs in rats. The antibacterial effects of 12 kinds of TTO’s components, extracted and commercial TTOs were measured by agar well diffusion method. Terpinolene (MIC 6.25%, MBC 100%),
α-terpinene (MIC 6.25%, MBC 25%), and α-terpineol (MIC 10%, MBC 40%) were the major components in TTOs and exhibited most potent antibacterial activity.
According to the above results, we designed the formulated TTOs. Formulated TTOs were more effect than extracted TTO but not as well as commercial one.
Allergic contact dermatitis model was established by neomycin irritations. The extracted TTO showed significant skin irritation at more than 2%/site, 1,8-cineole and terpinen-4-ol no significant dermal toxicity. Continued smear 2%/site TTO on Wistar rats skin for 28 days, GOT, GPT, BUN and creatinine of rats in serum did not significantly changed. We suggested TTO did not damage in the function of liver and kidney under 2%/site smear on skin for 28 days.
According to efficacy and safety literature review of evidence-based medicine and experimental research of TTO for acne treatment, TTOs were ability for
Staphylococcus aureus inhibition and anti-inflammatory activity. Topical used with low dose of TTOs rather than oral administration will not cause harm to health.
