不同地理品系臺灣杉葉子精油之化學多態性及其抗病媒蚊幼蟲活性

Abstract

臺灣杉（Taiwania cryptomerioides Hayata）為臺灣特有樹種之ㄧ，本研究為了解臺灣杉葉子精油是否有化學品系，共採集12個地理品系之臺灣杉葉子，以水蒸餾法萃取精油，並以氣相層析質譜儀（Gas chromatography-Mass spectrometry, GC-MS）分析其化學組成分。12個不同地理品系之臺灣杉葉子精油成分經群團分析（Cluster Analysis）及主成分分析（Principal Components Analysis, PCA）後，依組成分種類及相對含量可得到3個化學品系。α-Pinene型以α-Pinene為主成分，其相對含量 > 45%，且高於次要成分Limonene 30%以上；Limonene型以Limonene為主成分，其相對含量 > 45%，同時較次要成分α-Pinene多15%以上；Mixed型則是2個主要成分（α-Pinene及Limonene）相對含量皆小於50%，且兩者差異小於15%。 固相微萃取方法以100 μm PDMS 吸附纖維於25℃下吸附5 min之分析結果與臺灣杉葉子精油組成比例最為接近，相似度可達73.2%。經群團分析及主成分分析，其揮發物分群結果與精油結果一致，由此顯示固相微萃取技術可快速區分臺灣杉之化學品系。 抗埃及斑蚊（Aedes aegypti）與白線斑蚊（A. albopictus）幼蟲之活性，皆以八通關9（Limonene type）之效果最佳，試驗24 h後之半數致死濃度（Median lethal concentration, LC50）分別為41及75 μg/mL。但就統計結果而言，3種化學品系與抗病媒蚊幼蟲活性之相關性並不顯著。 林木之化學品系在應用上會有不同的價值，包括氣味的不同以及生物活性的差異。藉由臺灣杉葉子精油化學品系分析，將對往後其他生物活性試驗或利用上，提供良好的依據，未來亦有助於擴展臺灣杉天然物的利用領域及提高其經濟價值。

Taiwania cryptomerioides Hayata is an endemic species in Taiwan. In this study, to identify the chemical polymorphism of T. cryptomerioides, essential oils were extracted from leaves of twelve geographical locations by hydrodistillation and their chemical compositions were characterized using gas chromatography-mass spectrometry (GC-MS). According to the constituents of leaf essential oils and their relative contents obtained from GC-MS analysis, cluster analysis, and principal components analysis (PCA), the twelve geographical locations were divided into three chemotypes - limonene, α-pinene and mixed types. In α-pinene type, α-pinene is the major constituent (> 45%) and its relative content was 30% higher than limonene. In limonene type, limonene is the major constituent (> 45%) and its relative content was 15% higher than α-pinene. In mixed type, both of α-pinene and limonene were major constituents with relative content less than 50% and their content difference was less than 15%. Results from SPME showed that the most similar composition to essential oil was obtained by using 100 μm PDMS fiber which was carried out by heating at 25℃ and adsorption of volatile compounds for 5 min. The best constituent similarity between essential oils and volatile compounds is 73.2%. Through cluster analysis and PCA, 3 similar groups were obtained for the leaf essential oil. These results suggest that the SPME method could be used for rapid analysis of chemotype of T. cryptomerioides. The anti-mosquito 4th instar larva abilities of these 3 essential oils were investigated. Batongguan 9 (limonene type) have the best activity in 12 essential oils, its median lethal concentration (LC50) value against Aedes aegypti and A. albopictus 4th instar larvae in 24 h are 41 and 75 μg/mL, respectively. However, in statistics, the relationship between chemotype and anti-mosquito 4th instar larva abilities was no significant difference. According to flavor and bioactivity from different chemical compositions, there are different usages in different chemotypes. By analyizing T. cryptomerioides leaf chemical polymorphism, the results obtained provide valuable information for the selection of specific clones and for their utilization.