台灣潛力中草藥-苦瓜與香桂之活性成分及製程設計開發研究

Studies of two potential herbal medicines in Taiwan- Momordica charantia and Cinnamomum subavenium on their active constituents and large-scale development

劉瓊惠(Chiung-Hui Liu)

指導教授 ： 李志恒

高雄醫學大學/藥學院/藥學研究所/博士(2011年)

摘要

苦瓜(Momordica charantia L.)-葫蘆科(Cucurbitaceae)苦瓜屬(Momordica)植物，本研究由苦瓜莖部分離得到三個新化合物，分別為一個新multiflorane triterpenoid，3β-hydroxymultiflora-8-en-17-oic acid (1)以及兩個新cucurbitane triterpenoids，cucurbita-1(10),5,22,24-tetraen-3α-ol (2)與5β,19β-epoxycucurbita-6,22,24-trien-3α-ol (3)，化合物1-3之結構鑑定，依據圖譜數據及相關文獻資料比對而得；亦將此三個新化合物利用ABTS自由基清除效力試驗進行測定，其IC50 值分別為：268.5 ±7.9，352.1±11.5以及458.9±13.0 μM。此外，在xanthine oxidase (XO)抑制活性試驗中得到此三個新化合物之IC50 值分別為：142.3±30.2，36.8±20.5以及124.9±8.3 μM，顯示化合物1-3具有抗氧化之潛力。
而抗氧化劑(Antioxidants)近年來已被使用在心血管疾病、癌症及糖尿病等疾病的預防上。自由基(free radical)及活性氧(激活態氧，active oxygen)已被廣為認知與人類疾病癌症有關。因此，本研究持續找尋具有潛力之天然抗癌成分。主要探討由樟科(Lauraceae)植物-香桂(Cinnamomum subavenium)莖部所分離純化之化合物subamolide A對人類泌尿上皮癌細胞株NTUB1產生之毒殺作用及其導致細胞凋亡的可能致效機制與生物活性開發。研究結果發現相較於人類泌尿上皮細胞SV-HUC-1，subamolide A對於泌尿上皮癌細胞NTUB1及T24具有選擇性之毒殺作用。而subamolide A誘導泌尿上皮癌細胞凋亡之路徑經重複驗證是藉由破壞粒線體膜電位，並活化p53與ERK1/2來執行完成。
本研究同時為改善過去使用有機溶媒萃取方式所帶來之諸多缺點，改以有綠色溶媒之稱的超臨界二氧化碳(SCCO2) 萃取方法來萃取香桂莖部，並將研究所得十組萃取參數組合之香桂莖部超臨界二氧化碳萃取物進行細胞毒殺能力試驗，結果發現在第二組之香桂莖部萃取物其毒殺人類泌尿上皮癌細胞株NTUB1之活性為最佳，IC50=0.67 mg/mL。進ㄧ步以氣相層析串聯質譜儀(GC-MS)分析第二組香桂莖部萃取物之組成，分析結果顯示第二組香桂莖部萃取物中最主要之組成為subamolide A 35.1%，也是主要毒殺人類泌尿上皮癌細胞株NTUB1之活性來源。此外，第二組香桂莖部超臨界萃取物於濃度(1及2 mg/mL)之下，亦可協同性地增加cisplatin (1 mM)與gemcitabine (2 nM)於NTUB1中之細胞毒殺活性，也為泌尿上皮癌提供一個具有潛力及應用性的臨床治療方式。

關鍵字

苦瓜 ； 香桂

並列摘要

Momordica charantia L. (Cucurbitaceae), a new multiflorane triterpenoid and two new cucurbitane triterpenoids were isolated from the stems of Momordica charantia. The structures of the new compounds were elucidated by spectroscopic methods. These three new compounds, 1, 2 and 3 displayed ABTS radical cation scavenging activity with IC50 values of 268.5±7.9, 352.1±11.5 and 458.9±13.0 μM, respectively and an inhibitory effect on xanthine oxidase (XO) activity with IC50 values of 142.3±30.2, 36.8±20.5 and 124.9±8.3 μM, respectively. This finding indicated that 1-3 can be used as antioxidants.
Antioxidants have been used for prevention of cardiovascular disease, cancer and diabetes in recent years. The role of free radicals and active oxygen in the pathogenesis of human disease-Cancer. In the course of our continuing search for potential anticancer constituents from natural sources. This work was to study the cytotoxic effect of subamolide A, a constituent isolated from the stems of Cinnamomum subavenium and to extend its traditional use for clinical applications in treating human urothelial carcinoma. Subamolide A selectively induced apoptosis in two cancerous human urothelial carcinoma cell lines (NTUB1 and T24) in comparison with normal immortalized uroepithelial cells (SV-HUC-1). The current study demonstrated that subamolide A triggered the mitochondria-dependent apoptotic pathways and p53 and ERK1/2 activation in the human urothelial carcinoma cell line NTUB1.
Furthermore, in order to improve the drawback in organic solvent extraction, supercritical carbon dioxide (SCCO2, regarded as a “green” solvent) was applied to extract stems of C. subavenium. In addition, the IC50 value of ten different conditions of SFE extracts was determined by the MTT assay. Notably, SFE2 showed a significant cytotoxicity of growth in urothelial carcinoma cells NTUB1 (IC50=0.67 ?慊/mL). The chemical components of the fraction 2 extract were then identified by GC-MS. The results revealed that subamolide A is a major component (35.1%) in fraction 2. More impressively, SFE2 synergistically enhanced the cytotoxicity of cisplatin and gemcitabine in NTUB1 cells. Combinational cytotoxicity of SFE2 with CDDP or Gem provides
potential applications for the optimization of urothelial carcinoma (UC) treatment in clinic use.

並列關鍵字

Momordica charantia ； Cinnamomum subavenium

參考文獻

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