天然精油複合微膠囊應用於台灣鋏蠓之趨避效果及其效益評估

Repellent Effects of Applying Microencapsulation of Natural Essential Oils to Forcipomyia Taiwana

許博揚(PO-YANG HSU)

指導教授 ： 樓靜文 ； 呂兆倉

中臺科技大學/健康科學院/生物科技暨醫學工程研究所/碩士(2017年)

摘要

台灣鋏蠓(Forcipomyia taiwana)是台灣常見的騷擾性吸血昆蟲之一，台灣鋏蠓尚未被證實會傳播疾病，但其在各地盛行已造成嚴重危害而導致民眾的不便，居住在台灣鋏蠓盛行地區的居民生活深受其擾。精油的使用為近幾年來調查的主要材料，文獻指出精油具有的揮發性成分廣泛被運用於人類疾病的預防和治療。並指出精油對蚊蟲能夠產生一定的抑制性，然而精油的高揮發性會造成趨避時間較短進而導致無法達到長時間的趨避效果。
本研究針對8種市售天然精油:沒藥(Myrrh)、廣藿香(Pogostemon)、快樂鼠尾草(Salvia)、迷迭香(Rosmarinus)、乳香(Frankincense)、百里香(Thymus)、大茴香(Illicium)、安息香(Benzoin)，進行台灣鋏蠓之Y型管嗅覺器趨避測試，取得三種測試效果最為有效的精油以各樣的方式及不同比例進行精油混合之Y型管嗅覺器趨避測試，得到之最佳趨避參數，最後以幾丁聚醣作為殼材製備成微膠囊，評估其對釋放時間之影響以及包封後對其趨避之果效之影響進行探討。本研究將所製備之微膠囊以紅外線水分平衡儀(IMDB)，以確定膠囊的熱重損失、熱穩定性、包覆精油的重量及其控制釋放等性能。材料內在的化學結構則以傅立葉轉換紅外線光譜儀(FTIR)進行觀測，藉此得知膠囊是否成功將精油進行包覆。經由上述評估，以研究結果證實複合精油微膠囊是否具有更長效與更良好之趨避效果。
在本研究第一階段測試中我們得到八種天然植物精油針對台灣鋏蠓所進行之趨避測試中得到三個最佳的趨避精油分別為迷迭香(78.33%)、沒藥(78.67%)、及快樂鼠尾草(63.33%)。並在第一階段中發現迷迭香具有比趨避效果更進一步的降低活性效果。並將此前三佳之天然植物精油進行混和測試得到最佳精油比為RM沒藥及迷迭香等比例之混和。RM的混和效果可加強迷迭香所具有的降低台灣鋏蠓活性的效果。此階段可看見，當精油劑量相同材料濃度在劑量中進行最高比例之濃度提升，其效果會提高。並藉著網籠測試顯示其趨避率可達98.61 ± 1.13%的趨避效果。最後藉著FTIR測試發發現這些具有台灣鋏蠓趨避效果之植物精油，其原因是因其含有萜烯類此種成分，所以本研究之精油作為台灣鋏蠓之趨避劑是可行的。微膠囊的應用方面，由OM圖可得知幾丁聚醣/精油微膠囊是能正常成形的。並可發現當幾丁聚醣濃度越高，其粒徑越小，更可得到1.23 ± 0.31 µm趨近於奈米等級的微粒。藉著ATR-FTIR找出幾丁聚醣及精油官能基更進一步應證精油被正確包覆於幾丁聚醣微膠囊中。而精油包覆率及載藥量的部分，可得知當濃度越高載藥量包覆率也就越高。藉著細胞相容性及細胞毒性MTT測試更進一步證明殼材濃度越高會因殼材的保護而增加其生物活性。最終台灣鋏蠓網籠測試可得知2.5 wt %幾丁聚醣/精油微膠囊平均趨避率仍達87.26 %。測試結果表明本測試材料作為台灣鋏蠓趨避劑是可行的。

關鍵字

微膠囊 ； 天然植物精油 ； 台灣鋏蠓 ； 趨避

並列摘要

Forcipomyia taiwana (F. taiwana) is a common harassing haematophagous insect in Taiwan. It has not proven that F. taiwana does not spread insect-borne diseases, but the prevalence of this insect causes people inconvenience and harassment. Previous studies show that essential oils have volatile component and are thus extensively used to cure or prevent diseases. In addition, essential oils have inhibition against insects to a certain extent. The use of microcapsules further extends the release span of essential oils. Therefore, in this study, eight natural vegetation essential oils, including Myrrh, Pogostemon, Salvia, Rosmarinus, Frankincense, Thymus, Illicium, and Benzoin, are evaluated for the repellent test against F. taiwana using a Y-shaped tube of olfactory device. The top most effective essential oils are then mixed at different ratios and tested again for their repellent efficacy, thereby determining the optimal manufacturing parameters. Next, chitosan is used as the shell material of microcapsules that enwrap the essential oils. The release span of essential oils and the repellent effect of the microcapsules containing essential oils are examined. The microcapsules are measured in terms of wrapping rate, load rate, and release efficiency using an infrared moisture determination balance (IMDB). The interior chemical structure of microcapsules is evaluated using a Fourier transform infrared spectroscopy (FTIR), examining whether the essential oils are successfully encapsulated. The tests are performed in order to examine whether the encapsulated essential oils have a long acting and more efficient repellent efficacy.
According to the test results in the first stage, out of the eight essential oils, the top three ones with corresponding repellent efficacy are ranked from highest to lowest as Rosmarinus (78.33%), Myrrh (78.67%), and Salvia (63.33%); Rosmarinus is surprisingly found to have a lethal effect. In addition, the optimal essential oil blend is the Rosmarinus and Myrrh (RM) blend, which has the best repellent efficacy against F. taiwana. In this case, Rosmarinus has a strengthened effect to decrease the activity of F. taiwana. Therefore, the repellent efficacy of the blends is improved when the amount of single essential oil increases. The cage test results indicate that the maximum repellent efficacy of the blends reaches 98.61 ± 1.13%. Moreover, the FTIR test results show that the essential oils have a repellent efficacy against F. taiwana because they are composed of terpenyl, and using essential oils as a repellent is thus feasible.
On the other hand, OM chart confirms that the essential oil is encapsulated in chitosan microcapsules. A high concentration of chitosan results in a small particle size, which can reach 1.23 ± 0.31 µm and close to nano-grade particles. Moreover, ATR-FTIR spectrum confirms the functional groups of chitosan and essential oils, indicating that essential oils are enwrapped in chitosan microcapsules. The higher the concentration of chitosan, the higher the loading capacity and the higher the oil content. As far as cell biocopability and cytotoxicity are concerned, MTT assay proves that the shell material with a high concentration, the microcapsules exhibit greater biocompatibility. The essential oil microcapsules that are composed of 2.5 wt % chitosan have an average repellent rate of 87.26. The test results show that the combination of essential oils and chitosan microcapsules are qualified repellents against F. taiwana.

並列關鍵字

microcapsules ； natural vegetation essential oils ； Forcipomyia taiwana ； repellent

參考文獻

[1] 李學進, 小黑蚊, 科學與發展月刊, (2007) 40-45.

[2] 傅令嫻, 小黑蚊-台灣鋏蠓之實用知識, 臺灣兒童過敏氣喘及免疫學會學會通訊, 8 (2007) 18-19.

[3] M. Soonwera, S. Phasomkusolsil, Efficacy of Thai herbal essential oils as green repellent against mosquito vectors, Acta tropica, 142 (2015) 127-130.

[4] T.M. El-Sheikh, Z.I. Al-Fifi, M.A. Alabboud, Larvicidal and repellent effect of some Tribulus terrestris L.,(Zygophyllaceae) extracts against the dengue fever mosquito, Aedes aegypti (Diptera: Culicidae), Journal of Saudi Chemical Society, 20 (2016) 13-19.

[5] R. Pavela, Larvicidal property of essential oils against Culex quinquefasciatus Say (Diptera: Culicidae), Industrial Crops and Products, 30 (2009) 311-315.