許多植物中皆含有具抗癌作用的成分，如太平洋紫杉中的taxol、喜樹中的camptothecin。本實驗室自坊間收集一種宣稱具有抗癌活性特殊品種的Ipomoea batatas Lam.，進一步萃取其成分來進行抗癌活性分析。我們取Ipomoea batatas Lam.葉片甲醇萃取物，再利用水與乙酸乙酯分離，取得乙酸乙酯萃取物，簡稱IB-EAE（Ipomoea batatas ethyl acetate extract）。由離體癌細胞增生試驗，發現IB-EAE對於許多癌細胞皆具有抑制生長的作用。並且由活體實驗，發現IB-EAE能夠抑制小鼠黑色素癌細胞B16F10、小鼠肺癌細胞LLC與小鼠肝癌細胞ML-1 4a原位腫瘤的生長。接著我們進一步探討IB-EAE抑制腫瘤生長的機制。
　　
　　利用流式細胞儀（FACScan）與BrdU嵌入試驗，發現IB-EAE抑制癌細胞增生之原因，主要是藉由抑制細胞由G1期進入S期，使細胞週期停止。另外觀察IB-EAE對於腫瘤血管新生（angiogenesis）的影響。由離體外，發現IB-EAE能夠抑制牛大動脈內皮細胞BAEC移行的能力。於ex vivo與semi in vivo，發現IB-EAE能夠抑制主動脈微脈管的形成與雞胚胎絨毛膜的血管新生。最後由活體試驗，發現IB-EAE能夠抑制腫瘤組織中血色素（hemoglobin）的含量。由以上結果，顯示IB-EAE具有抑制血管新生的活性。最後觀察IB-EAE對於腫瘤轉移（metastasis）之影響。由離體外癒合試驗與癌細胞移行試驗，發現IB-EAE能夠抑制高轉移性的B16F10細胞與PC-3細胞移行的能力。由酶譜電泳分析（gelatin zymography），發現IB-EAE能夠抑制PC-3細胞分泌MMP-9，並且能夠降低活體腫瘤組織間質液內MMP-9的活性，由此顯示IB-EAE可能具有抑制腫瘤轉移的活性。

　　Many anticancer drugs are derived from nature, such as taxol and camptothecin. A specific variety of Ipomoea batatas Lam obtained from local market is tested for its anticancer activity. The leaves were extracted with methanol and then partitioned with water and ethyl acetate. The ethyl acetate extract （IB-EAE）is found to exert significant cytotoxicity against several cancer cell lines tested in vitro in a dose-dependent manner. The anticancer activity of IB-EAE was investigated further in vivo using mouse bearing transplanted tumor cells. IB-EAE significantly inhibits the growths of tumors originating from B16F10 melanoma, LLC carcinoma and ML1-4a hepatoma.
　　
　　Flow cytometry assay and BrdU incorporation assay show that the inhibitory activity of cell proliferation is due to cell cycle arrest because IB-EAE inhibits the progression of cells from G1 phase into S phase. Besides, we found IB-EAE inhibits the migration activity of BAEC in vitro, and the microvessels formation of aortic ring ex vivo as well as the blood vessel formation in a semi in vivo chicken chorioallantonic membrane assay. Finally, by measuring total hemoglobin content in the tumor tissues, we demonstrate that IB-EAE does possess anti-angiogenic activity. We also found IB-EAE inhibits the migrations of PC-3 human prostate cancer cells and B16F10 mouse melanoma cells by either the Boyden chamber assay or the wound healing assay. In a gelatin zymography assay for matrix metalloproteinase-9 (MMP-9), IB-EAE inhibits the secretion of MMP-9 form PC-3 cells and the total MMP-9 activity in the B16F10 tumors, suggesting the extract possesses an interesting anti-metastatic principle.

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