錫蘭肉桂萃取物及其揮發性成分對小花蔓澤蘭植物毒性之探討

The phytotoxicities of extracts and volatile compounds of Cinnamomum zeylanicum against Mikania micrantha

傅淑芳(Shu-Fang Fu)

指導教授 ： 顏才博

國立屏東科技大學/農學院/熱帶農業暨國際合作系所/碩士(2011年)

https://doi.org/10.6346/NPUST.2011.00040

摘要

入侵雜草小花蔓澤蘭（Mikania micrantha Kunth）開花後產生大量種子，並攀附於植物造成其死亡，目前對臺灣之林木與一些果園造成嚴重的威脅，因此如何利用天然生物成分，有效抑制小花蔓澤蘭種子發芽及生長，並維持生態安全，成為一重要課題。相剋作用是植物利用自身之植物毒性而影響周圍環境或鄰近植物之生長發育。本研究分析探討錫蘭肉桂（Cinnamomum zeylanicum Blume）葉部與枝條水溶萃取液以及其精油對小花蔓澤蘭種子發芽生長之植物毒性。結果顯示，葉部水溶萃取液、精油與反式肉桂醛、丁香酚及桂皮乙酸酯三種揮發成分皆呈現強烈植物毒性，能有效抑制種子發芽、幼根與莖部之生長。錫蘭肉桂葉部精油經GC/MS分析，發現含有13種成分，其中以反式肉桂醛和丁香酚佔總含量的45.07%和40.66%。並將錫蘭肉桂葉部精油與其成分對小花蔓澤蘭進行植物毒性分析，發現錫蘭肉桂葉部精油及其主要成分對小花蔓澤蘭幼根之半數抑制率，由低至高依次為桂皮乙酸酯（50 μg/mL）< 反式肉桂醛(68 μg/mL) < 精油(107 μg/mL) < 丁香酚 (198 μg/mL)。此外並以分光光度計，評估各水溶萃取液、精油和成分對小花蔓澤蘭四種抗氧化酵素之影響。酵素分析結果發現，過氧化氫酵素(CAT)在葉部水萃液1%時及超氧化物歧化酵素(SOD)和穀胱甘肽還原酵素(GR)活性在丁香酚濃度500 μg/mL時其活性增加百分率皆最高，抗壞血酸過氧化物酵素(APX)則是在葉部精油濃度500 μg/mL時活性增加百分率最高。當小花蔓澤蘭受到錫蘭肉桂葉部水溶萃取液、精油及其揮發性成分逆境處理時，為了降低氧化壓力與清除過多的活性氧化物（ROS），因此SOD、CAT、APX、GR酵素活性均會提高。且以介質土培養的小花蔓澤蘭幼苗，以丁香酚高濃度每日澆灌10 ml兩天後，其根部呈現萎縮且倒塌的現象。推論是因為氧化壓力超載，使抗氧化酵素系統遭受破壞，而使SOD、APX、GR酵素活性降低。綜合以上結果顯示，錫蘭肉桂之萃取物與揮發性成分，具有明顯抑制小花蔓澤蘭之活性，未來有潛力開發為控制小花蔓澤蘭之天然除草劑。

關鍵字

小花蔓澤蘭 ； 錫蘭肉桂 ； 相剋作用 ； 植物毒性

並列摘要

Mikania micrantha Kunth is a major invading weed in Taiwan causing serious ecological problems due to its fast growth rate and the tremendous amount of seeds that it produces. Reducing the damages caused by M. micrantha and the pollution of agrochemical have become important issues and chellanges for the modern agricultural practice in Taiwan. Natural allelochemicals from plants might provide an alternative solution to the problems as those phytochemicals are biodegradable in nature. Cinnamomum zeylanicum Blume is an aromatic plant and has been used as food additives, perfume ingredient, or herb medicine, but its phytotoxicity is still unknown. For the reasons above, this study was to investigate the phytotoxicities of C. zeylanicum against M. micrantha. In addition, in order to elucidate the possible mechanisms of phytotoxicity, antioxidative enzymes activities in M. micrantha were examined following the inducements of effective extracts and compounds. Chemical composition of essential oil was analyzed by gas chromatograph and mass spectrometry (GC/MS). Phytotoxicity was determinated by the inhibition of germination, radicle and stem growths of M. micrantha. Four antioxidative enzymes, superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR), were analyzed using spectrophotometer. The results showed that aqueous extracts, essential oil and three major volatile compounds from C. zeylanicum exhibited significant phytotoxicities against M. micrantha. GC/MS analysis revealed that the leaves essential oil consists of a total of thirteen compounds which are dominated by trans-Cinnamaldehyde (45.07%) and Eugenol (40.66%). The IC50 (50% inhibitory concentration) values of essential oil and three major compounds on radicle growth were: Cinnamyl acetate (50 μg/mL) < trans-Cinnamaldehyde ( 68 μg/mL) < essential oil (107 μg/mL) < Eugenol (198 μg/mL)。CAT enzyme activities increased mostly when treated with leaf aqueous extract at 1%. SOD and GR enzymes reached the highest activities at the treatment of 500 μg/mL Eugenol, while APX also had the highest activity at the treatment of 500 μg/mL essential oil. However, SOD, APX and GR activities dramatically declined under the treatment of 1000 μg/mL Eugenol. It is possible that the concentration of Eugenol exceeded the capacity of enzyme system in M. micrantha, resulting in the dysfunction of enzymatic activities. In conclusion, the aqueous extracts, Eugenol, Cinnamaldehyde and Cinnamyl acetate from C. zeylanicum were very effective in inhibiting M. micrantha, and have high potential to be formulated as natural herbicide in controlling M. micrantha.

並列關鍵字

Mikania micrantha ； Cinnamomum zeylanicum ； Allelopathy ； ptyhytotoxici

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