柳杉精油運用於衣魚防治之研究

Abstract

本研究為首篇針對天然物運用於抗衣魚活性評估之研究論文。衣魚（Lepisma saccharina）為原始無翼之昆蟲，其取食來源種類繁多，包括紙張、棉類、澱粉、穀類等均為其食物來源，亦是一般居家環境中常見之害蟲。本論文選擇柳杉（Cryptomeria japonica）精油為研究對象，針對其可能具有之衣魚忌避及致死活性進行評估。為了進行忌避和致死試驗，本研究首先對衣魚進行飼養及孵化條件測試，於實驗後得知最適合衣魚生長之條件為紙張纖維與混合飼料 (酵母粉：麥皮：高蛋白＝9：9：1) 混合比例為1：1時之生長狀況最佳；另外，衣魚卵並不需要成蟲的孵化，而蟲卵的生活條件則與成蟲一致。由忌避試驗結果證實，葉部和材部精油對於衣魚皆具有極佳之忌避活性，當葉部精油使用量為0.01 mg/cm3時，忌避率可達76%；而材部精油使用量若為0.001 mg/cm3時，忌避率可達83%。此外，衣魚處在葉部精油使用劑量為0.16 mg/cm3之環境中，於10小時內衣魚可被完全殺死；若使用材部精油為0.16 mg/cm3劑量之環境中，16小時內衣魚即完全被致死。本研究並利用氣相層析質譜儀分析葉部精油，以及藉由微固相萃取技術收集於忌避試驗裝置內所揮發出之揮發成分組成。結果顯示，柳杉葉部精油之主要成分為Elemol (18.22%)、16-Kaurene (11.63%)、3-Carene (9.66%)、Sabinene (9.37%)、Terpinene-4-ol (9.06%)、α-Eudesmol (5.70%)、α-Pinene (5.62%) 和 Limonene (5.26%)；至於揮散於作用環境之精油成分則以3-Carene (21.03%)、p-Cymene (10.95%)、Limonene (9.49%)、β-Myrcene (9.39%)、γ-Terpinene (9.10%)、4-Carene (8.57%)、Terpinene-4-ol (7.97%)為主要成分。於柳杉材部精油分析方面，分析結果得知主要成分為γ-Cadinene (17.70%)、δ-Cadinene (13.08%)、Elemol (9.47%)、Germacrene D (6.31)、α-Muurolene (4.02%)、β-Eudesmol (3.66%)和β-Cubene (3.37%)；而揮散於忌避試驗環境中之成分則為γ-Cadinene (50.55%)、α-Muurolene (9.59%)、β-Caryophyllene (4.77%)、α-Humulene (3.92%)、δ-Cadinene (3.41%)。由本論文之研究結果得知，柳杉精油確具有開發成符合環保要求的居家防蟲產品之潛力，未來將可進行劑型的開發以及安全性評估，如此應可賦予柳杉造林木新的利用價值。

This is the first paper to evaluate a natural product used as an antisilverfish agent all over the world. Silverfish (Lepisma saccharina), primitive wingless insects, feed on a variety of materials, including paper, cotton, starch and cereals. It is a general common pest of house. In this study, the essential oils of Cryptomeria japonica were selected to evaluate its effect of repellent and death against silverfish. Before repellency and anti-silverfish assay, the culture system for silverfish was established in this study. The best feeds for silverfish were cellulose and mixed feed in a 1:1 ration (the composition of mixed feed was milk powder: oatmeal: yeast= 1: 9: 9). Moreover, the hatching process was not necessary for the mature of silverfish eggs. According to the results obtained in the repellency assay, the essential oil of leaves and woods from C. japonica shown the significantly repellency activity against silverfish. The repellent activity was 76% at a dosage of 0.01 mg/cm3 essential oil from leaves. In addition, the repellent activity was 83% at a dosage of 0.001 mg/cm3 essential oil from woods. When silverfish were exposed to a concentration of 0.16 mg/cm3 essential oil from leaves, they were killed within 10 h, and exposed to a concentration of 0.16 mg/cm3 essential oil from wood, they were killed within 16 h. The chemical composition of essential oil, the emissions from a test chamber, and the residue left on filter papers previously soaked with essential oil in a chamber were analyzed by gas chromatography-mass spectrometry. The main components of the leave essential oil were found to be: elemol (18.22%), 16-kaurene (11.63%), 3-carene (9.66%), sabinene (9.37%), terpinene-4-ol (9.06%), α-eudesmol (5.70%), α-pinene (5.62%), and limonene (5.26%). As for the wood essential oils were γ-cadinene (17.70%), δ-cadinene (13.08%), elemol (9.47%), germacrene D (6.31), α-muurolene (4.02%), β-eudesmol (3.66%), and β-cubene (3.37%). Only some constituents of the essential oil compounds collected by solid-phase microextraction were found to be emitted in the test chamber. The main composition for leave essential oil were 3-carene (21.03%), p-cymene (10.95%), limonene (9.49%), β-myrcene (9.39%), γ-terpinene (9.10%), α-terpinene (8.57%), terpinene-4-ol (7.97%); for wood essential oil were γ-cadinene (50.55%), α-muurolene (9.59%), β-caryophyllene (4.77%), α-humulene (3.92%), and δ-cadinene (3.41%). Based on the results from this study, the essential oils from C. japonica provide a great potential for developing an environmental-friendly chemicals to prevent silverfish to damage living environment.