木蠟樹葉之生物活性成分研究

本研究乃針對木蠟樹 (Rhus succedanea L.) 的葉部 (leaves) 進行成分分離及生物活性的探討。由木蠟樹 (R. succedanea L.) 葉部的甲醇萃取液中分離到四個已知化合物，分別為 beta-amyrin acetate (1)、beta-amyrin (2)、beta-sitosterol (4) 及lantabetulic acid (5)。並且以 beta-amyrin (2) 為原料合成其衍生物為新化合物 beta-amyrin succinate (3)，之後探討 beta-amyrin acetate (1) 與 beta-amyrin succinate (3) 這類五環三萜類 (pentacyclic triterpenes) 化合物對於NTUB1人類膀胱癌細胞毒殺活性、誘導或抑制活性氧分子 (Reactive Oxygen Species, ROS) 作用及腫瘤細胞週期停滯 (cell cycle arrest) 研究。結果顯示 beta-amyrin acetate (1) 針對人類膀胱癌細胞 (NTUB1 cells) 及人類前列腺癌細胞 (PC3 cells) 的細胞毒殺活性相對於 beta-amyrin succinate (3) 顯得較弱，因此並未繼續做深入的探討；另一方面，beta-amyrin succinate (3) 則是顯示出較強的細胞毒殺活性，因此選用其做進一步探討。結果發現 beta-amyrin succinate (3) 有誘導ROS產生的作用，在cell cycle distribution 的檢測上，beta-amyrin succinate (3) 在較低濃度 (25 uM) 可能會因ROS之增加導致G1 phase arrest，最後使細胞經由apoptosis而死亡；在較高濃度 (50 uM及75 uM) 則可能由於細胞內增生之ROS使NTUB1細胞週期停滯在G2/M phase，因此產生細胞凋亡而死亡。綜合以上，beta-amyrin succinate (3) 可能係經由ROS之增加導致cell cycle arrest，並伴隨apoptosis而使癌細胞死亡。

關鍵字

木蠟樹；三萜類；細胞毒殺活性

並列摘要

Four known compounds, beta-amyrin acetate (1), beta-amyrin (2), beta-sitosterol (4), and lantabetulic acid (5) were isolated from the leaves of Rhus succedanea L. by chromatographed with silica gel column. Their structures were determined by spectroscopic methods. beta-Amyrin succinate (3) was a new derivative compound synthesized from beta-amyrin (2). In pharmacological studies, beta-amyrin acetate (1) showed weak cytotoxic activity than that of beta-amyrin succinate (3), thus we didn’t do more research on it. beta-Amyrin succinate (3) showed significant increase of ROS production. In cell cycle distribution assay, beta-amyrin succinate (3) at 25 uM, 50 uM and 75 uM induced G1 and G2/M phase cell cycle arrest, accompanied increased amount of sub-G1 phase, respectively. It clearly indicated that the increased amount of ROS in NTUB1 cells treated with 25 uM, 50 uM and 75 uM of beta-amyrin succinate (3) may induce cell cyle arrest at G1 phase and G2/M phase, respectively, accompanied increased amount of sub-G1 peak. The result indicated that the cell cycle arrest at G1 or G2/M phase may mediate through the increased amount of ROS and induced cell death due to apoptosis in NTUB1 cells treated with beta-amyrin succinate (3).