台灣肖楠葉子精油及成分抗病媒蚊活性之研究

Mosquitocidal Activities of Leaf Oil and Its Constituents from Calocedrus macrolepis var. formosana

柯季宏(Chi-Hung Ko)

指導教授 ： 張惠婷

共同指導教授 ： 張上鎮

國立臺灣大學/生物資源暨農學院/森林環境暨資源學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.01829

摘要

埃及斑蚊與白線斑蚊是登革熱的主要病媒蚊，目前並無有效的登革熱疫苗，因此病媒蚊的防治是非常重要的措施。近年來許多專家學投入天然植物抽出物的研究，希望能找出有效的抗病媒蚊成分來取代化學藥劑的使用。台灣肖楠(Calocedrus macrolepis var. formosana)為台灣特有的樹種，為了評估台灣肖楠葉部精油之抗病媒蚊活性，本試驗萃取了12種台灣肖楠葉子的精油，經由氣相層析-質譜儀(GC-MS)與群團分析，可依據精油成分將其分成3種化學品系:Limonene(檸檬烯)型、α-Pinene(α-蒎烯)型與混合型，皆具有不錯的抗病媒蚊活性，進一步評估精油成分的活性，其抗病媒蚊活性大小為(-)-Limonene > (+)-Limonene ≒ β-Caryophyllene ≒ (-)-α-Pinene >β-Myrcene ＞β-Pinene ≒ (+)-α-Pinene，以Limonene之抗病媒蚊活性最佳。

比較精油及其成分的抗病媒蚊試驗結果，顯示精油及其成分抗埃及斑蚊的活性比白線斑蚊較佳。本試驗亦探討化合物旋光性與抗病媒蚊活性之間的關係，試驗結果顯示旋光性的不同會影響抗病媒蚊活性，而右旋與左旋對於抗病媒蚊活性之優劣則因化合物而異，台灣肖楠葉部精油中的Limonene與α-Pinene均以左旋結構的抗病媒蚊活性較強，(-)-Limonene對埃及斑蚊幼蟲之LC50僅為14μg/mL。進一步評估Limonene對白線斑蚊與埃及斑蚊幼蟲生長及成蚊之不孕性的影響，試驗結果發現在低濃度(10μg/mL)時，Limonene即可使病媒蚊幼蟲的化蛹率及羽化率下降，同時可以有效降低成蚊的產卵數以及卵的孵化率。綜合試驗結果顯示台灣肖楠葉部精油以及精油成分具有非常良好的抗病媒蚊潛能，值得進一步的開發與利用。

關鍵字

台灣肖楠 ； 精油 ； 氣相層析-質譜儀 ； 群團分析 ； 化學品系 ； 埃及斑蚊 ； 白線斑蚊 ； 抗病媒蚊活性 ； 檸檬烯

並列摘要

Aedes aegypti and Aedes albopictus are main vectors of dengue fever. There is no effective vaccine for dengue fever thus far. Therefore, control of mosquito population is the best way to control and prevent dengue fever. Many experts have tried to find mosquitocidal natural products to replace synthetic insecticides in recent years. Calocedrus macrolepis var. formosana is an endemic tree species in Taiwan. To evaluate mosquitocidal activities of leaf oils from Calocedrus macrolepis var. formosana, leaf oils from twelve sources were extracted and chemical constituents were analyzed by GC-MS in this study. According to the chemical composition of essential oil, leaf oils of C. macrolepis var. formosana from different sources could be classified into three chemotypes: Limonene chemotype, α-Pinene chemotype and mixed chemotypes by cluster analyses. All chemotype oils possess the larvicidal activity against mosquito larvae. Larvicidal activities of main constituents of leaf oil were also evaluated, results ranked in descending order of larvicidal activity: (-)-Limonene > (+)-Limonene ≒ β-Caryophyllene ≒ (-)-α-Pinene > β-Myrcene ＞β-Pinene ≒ (+)-α-Pinene. Limonene possesses the best mosquitocidal activity.

Results of larvicidal tests demonstrated that leaf oils from C. macrolepis var. formosana and its constitunets had better mosquitocidal activities against Ae. aegypti than Ae. albopictus. In addition, influence of the optical activity on the larvaicidal activity of enantiomers was investigated. Results indicated that the optical activity can affect larvicidal activities of enantiomers. Varied effects of the optical activity on larvicidal activities of enantiomers occurred in different constituents. Levorotatory(-) isomer of both Limonene and α-Pinene, main larvicidal constituents of leaf oil, possess the better larvicidal activity than that of dextrorotatory(+) isomer. (-)-Limonene had the best mosquito larvicidal activity with an LC50 of 14 μg/mL. Furthermore, the effects of Limonene on growth inhibiting, ovicidal activities and egg hatchability of Ae. aegypti and Ae. albopictus were also discussed in the research. Results showed the growth, pupal development and eclosion of mosquito pupae were retarded by Limonene at low concentration (10μg/mL). Limonene also interfered with oviposition and egg hatchability of mosquitoes. The average number of eggs laid (per female) and hatching rate of egg of mosquitos were significantly decreased after Limonene treatment. These data indicate that leaf oil of C. macrolepis var. formosana and its constituents have great potential as natural insecticide in mosquito control and are worth further exploring.

並列關鍵字

Calocedrus macrolepis var. formosana ； Essential oil ； GC-MS ； Cluster analyses ； Chemotype ； Aedes aegypti ； Aedes albopictus ； Mosquitocidal activities ； Limonene.

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