台灣重要入侵外來種植物之抗氧化及美白功能之研究

Abstract

入侵外來種(alien invasive species)由IUCN定義為已於自然或半自然生態環境中建立穩定族群，並可能進而威脅原生生物多樣性者。台灣目前有許多因不同目的引進之外來種植物，而2008年農委會公佈台灣十大入侵外來種植物，分別為小花蔓澤蘭、香澤蘭、銀合歡、豬草、大黍、銀膠菊、象草、槭葉牽牛、馬櫻丹以及與布袋蓮，然而目前防治方法仍然使用物理伐除居多，若可開發入侵植物之利用價值，期望可增加伐除之誘因以減少其對本土生態環境之影響。目前尚未有報告針對其美白功能進行研究，因此實驗將針對此方向進行討論。以水及乙醇進行萃取得到十大入侵外來種植物之水及乙醇萃取物，水萃取物之萃取率介於3.0~29.0%，乙醇萃取物之萃取率介於7.8~19.0%之間。體外試驗測試其清除自由基的能力，在清除DPPH自由基的部份，銀合歡水萃取物具有最佳抑制效果IC50為0.16mg/ml；清除ABTS自由基的部份，銀合歡水萃取物具有最佳抑制效果IC50為0.15mg/ml；酪胺酸酶活性抑制試驗僅有銀合歡水萃取物具有抑制效果，且隨著萃取物濃度增加而增加；總酚含量測試結果銀合歡水萃取物具有相較最高的總酚含量為231.8mgGA/gextract。細胞內使用小鼠黑色素瘤細胞 (B16F0)，測試外來種植物之萃取物對B16F0細胞存活率，得到6種植物之水及乙醇萃取物的細胞存活率皆＞80%。其中以槭葉牽牛與銀合歡水萃取物抑制酪胺酸酶的活性與抑制黑色素生成的效果最佳，針對槭葉牽牛與銀合歡水萃取物於B16F0細胞內探討，皆具有time-dependence及does-dependence之相關性。實驗最後收集與樣品反應過後的細胞團塊，發現槭葉牽牛水萃取物與正對照組1mM麴酸具有使細胞塊白化的現象。實驗結果發現，實驗樣本皆為植物粗萃取物，然而實驗結果都近正對照組之美白效果，倘若可以更深入將植物內有效成份分離出來進行更深入研究，期望得到更佳的效果，進而達到原先預期的目標。

IUCN definded invasive alien species were animals, plants or other organisms introduced by man into places out of their natural range of distribution, where they become established and disperse, generating a negative impact on the local ecosystem and species. There are many different purpose for introduction of invasive alien species in Taiwan, contains Mikania micrantha, Chromolaena odorata (L.) R. M. King & H. Rob., Leucaena leucocephala, Pennisetum purpureum Schum., Panicum maximum Jacq., Parthenium hysterophorus L., Ambrosia artemisiifolia, Ipomoea cairica (L.) Sweet, Lantana camara L. and Eichhornia crassipes (Mart.) Solms. However, there were still using physical harvesting control methods, if the invaseive plants can be utilizated using the value expected increase harvesting to reduce their impact on the local ecological environment. Report not yet available to study for its whitening properties, so we examined 10 invasive alien plants that might be useful for skin-whitening and skin health. Samples were extract with water and ethanol. The yields of these water extracts were 3.0~29.0%, and ethanol extracts were 7.8~19.0%. Antioxidant test of extracts were tested for free radical scavenging effect. The water extract of Ipomoea cairica (L.) Sweet showed good free radical scavenging effect and high phenolic contents (IC50:0.16mg/ml, DPPH radical; IC5 0 :0.15mg/ml,ABTS radical and 231.8mg of Gallic acid/g extract). And only the water extract of Ipomoea cairica (L.) Sweet showed inhibitory effects on mushroom tyrosinase activity. And the inhibition were doesdependent. In vivo test of extracts (1mg/ml) were tested for cell viability on mouse melanoma cell B16F0; 6 plant extracts exhibited low cytotoxicity. The water extract of Ipomoea cairica (L.) Sweet and Leucaena leucocephala, exhibited potent inhibitory iii effects on tyrosinase and melanin. And the inhibition were does-dependent and timedependent. The water extract of Ipomoea cairica (L.) Sweet exhibited whitening effect on B16F0 cell pellet. It was found that , the sample were crude extract, results are close to the positive control include 1mM kojic acid and 1mM ascorbic acid of the whitening effect. If we can separation of the active compound for further research. Expect better results, and thus achieve the original intended objective.