- 期刊
烏心石抽出成分之抗腐朽菌活性評估
Evaluation of Antifungal Activities of Extractives from Michelia Formosana
摘要
烏心石(Michelia formosana (Kanehira) Masamune & Suzuki)為台灣原生樹種，屬於台灣闊葉五木之一。本研究目的為評估抽出成分對於烏心石木材耐腐朽性的影響，以及分析心材、邊材、樹皮與葉子抽出物的抗腐朽菌活性。試驗結果得知烏心石邊材經過Lenzites betulina白腐菌與Laetiporus sulphureus褐腐菌木塊腐朽試驗後，試材的重量損失率分別為32.4%與45.1%，顯示邊材不具有耐腐朽性；心材對於2種腐朽菌的重量損失率均低於2%，證實心材的抗腐朽性極佳。而心材經乙醇萃取後，對於腐朽菌L. betulina與L. sulphureus的抗腐朽性明顯降低，試材的重量損失率上升為16.4%與30.1%，表示抽出成分對心材的抗腐朽性具有重要的影響。評估烏心石各部位乙醇抽出物抑制腐朽菌的活性，其活性依序為心材＞葉部＞邊材＞樹皮，證實心材的乙醇抽出物具有良好的抗腐朽菌活性。進一步評估心材抽出物中各可溶部的活性，以正己烷可溶部的抗菌活性最佳，試驗濃度為100μg/mL時，對白腐菌L. betulina的抗菌指數為67%，對褐腐菌L. sulphureus亦可達到83%的抑制效果，其次是正丁醇可溶部、乙酸乙酯可溶部及水可溶部，綜合上述結果顯示具抑制腐朽菌活性的心材抽出成分主要存在於正己烷可溶部。
並列摘要
Michelia formosana (Kanehira) Masamune & Suzuki is one of the five precious hardwood trees in Taiwan. The objectives of this study were to evaluate the influence of extractives on the decay resistance of M. formosana wood and analyze the antifungal activities of extracts from heartwood, sapwood, leaf and bark. After decay tests with white rot fungus Lenzites betulina and brown rot fungus Laetiporus sulphureus, weight losses of sapwood specimens are 32.4% and 45.1%, respectively. It revealed that the sapwood was not durable. Weight losses of heartwood specimens were less than 2% against 2 kinds of rot fungi. Heartwood demonstrated high decay resistance against wood rots. However, weight losses of extracted heartwood specimens were significantly increased to 16.4% and 30.1% after exposure to fungi L. betulina and L. sulphureus, respectively. It indicated that the ethanolic extract had a strong influence on the decay resistance of heartwood. Antifungal activities of ethanolic extracts obtained from M. formosana were in the following order: heartwood＞leaf＞sapwood＞bark. Result inferred that the heartwood ethanolic extract exhibited the highest antifungal activity. Further, antifungal activities of n-Hexane, EtOAc, n-BuOH and H2O-soluble fractions obtained from heartwood ethanolic extract were assessed, the activities observed were in the order of n-Hexane＞n-BuOH＞EtOAc＞H2O-soluble fractions. At the concentration of 100µg/mL, the n-Hexane-soluble fraction showed the antifungal indexes of 67% and 83% against rot fungi L. betulina and L. sulphureus, respectively. These results indicated that the antifungal compounds mainly existed in the n-Hexane-soluble fraction.