Euphorbia neriifolia為灌木狀多肉植物。在臺灣民間相傳，可用來治療各種疾病包括癌症。為了瞭解E. neriifolia是否真的具有治療癌症的功效，我們利用各種離體外( in vitro)和活體內( in vivo)實驗去探討E. neriifolia的可能潛在抑癌活性。我們將E. neriifolia的乙醇粗萃取物，以水和乙酸乙酯去分層萃取，得到乙酸乙酯萃取物，簡稱為EN-EAE。細胞毒殺實驗結果顯示，EN-EAE有抑制人類結腸癌(SW480)、小鼠路易士肺癌(LLC)以及小鼠黑色素瘤癌細胞增生的能力，且呈現劑量效應正相關性。在小鼠原位癌的路易士肺癌動物模式中，發現由腹腔注射10 mg/kg以及20 mg/kg的EN-EAE，能夠有效的降低腫瘤的體積和重量。分析EN-EAE對於人類結腸癌(SW480)的細胞週期的影響，發現在24小時，細胞週期停頓在G2/M期，而隨著時間的延長，癌細胞的SubG1期的比例增加。進一步地， DNA片段化洋菜膠電泳分析和Hoechst 33258染色，均證實EN-EAE能誘使癌細胞發生細胞凋亡的現象。大鼠主動脈環實驗結果顯示， 125 µg/ml的EN-EAE能明顯抑制微血管網的形成。另外，離體癒合試驗和人類攝護腺癌細胞(PC3)移行試驗，均顯示80 µg/ml 的EN-EAE，可以抑制癌細胞因受到化學驅向性物質的吸引而移動的能力。而以80 µg/ml的EN-EAE處理PC3細胞，並進行酶譜電泳分析，發現PC3細胞的MMP-9分泌量降低。
顯示著E. neriifolia具有抗癌功效，值得進一步純化分離，並探討其有效化學活性成分的可能作用機制。

Euphorbia neriifolia is a succulent and cactus-like shrub which has been used as a folk medicine in Taiwan for the treatment of various diseases including cancer. This study aims at investigating the antitumor activities of E. neriifolia. We performed various antitumor experiments in vitro and in vivo to evaluate its potential antitumor activities. The dry powder of whole plant was extracted with 50% ethanol and then partitioned with ethyl acetate and water to yield an ethyl acetate extract (11%) and aqueous extract (1%). The ethyl acetate extract ,abbreviated as EN-EAE, showed significant cytotoxicities against some cell lines, including Lewis lung carcinoma (LLC), B16F10 melanoma and SW480 human colon adeno-carcinoma in a dose-dependent manner. In vivo tumor model using implanted LLC revealed that the EN-EAE extract significantly reduced the tumor size when C57/BL6 mice were treated with EN-EAE i.p.q.d. at a dose of 10 and 20 mg/kg. Flow cytometry analysis revealed that EN-EAE induced SW480 tumor cells to undergo cell cycle arrest in the G2/M phase within 24 hrs and increased cell population at sub-G1 phase in a dose and time-dependent manner. DNA fragmentation assay and Hoechst 33258 nuclear staining confirmed that cytotoxicity of EN-EAE was due to apoptosis. Rat aortic ring assay indicated 125 µg/ml EN-EAE also inhibited the outgrowth of endothelial cell from rat arotic ring and further micro-vessel web formation. In addition, EN-EAE at 80 µg/ml had no effect on the proliferation of PC3 cells in culture but suppressed the cell movement as assayed by the wound healing experiment. The suppression is echoed by its inhibition of PC3 cell migration initiated by chemoattractant in the Boyden chamber assay. Gelatin zymography assay showed 80 µg/ml EN-EAE reduced the secretion of matrix metalloproteinase-9 (MMP-9) from PC3 cells. The results combined indicate that EN-EAE possesses antitumor activities. E. neriifolia is worthy of further investigation to obtain its active constituent and to study its possible molecular mechanism of action.

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