| Abstract: | 洛神花(Hibiscus sabdariffa Linnaeus)為錦葵科(Malvaceae)植物，原產熱帶地區，分部於印度，馬來西亞及東南亞，台灣東部及南部也盛產。由於本研究室致力於開發可食用之天然物中之Chemopreventive agents，希望可以由攝取食品來達到預防或延緩癌症。所以，本研究以台灣特有之洛神花，從中分離之花青素探討其功能。花青素(Anthocyanins)廣泛存於蔬菜、水果等植物中，已有許多報告證明花青素具抗氧化活性，降低血脂肪及防癌等作用，本研究室也發現分離自洛神花之花青素(Hibiscus anthocyanins, HAs)有抗氧化及保肝之功能。最近的數據也顯示此類HAs會促進癌細胞凋謝死亡，尤其以血癌細胞(HL-60)最為明顯，因此，本研究擬深入探討HAs之抗癌作用及其作用之分子機制。首先，利用Flow cytometer及DNA fragmentation分析，結果發現HAs促進HL-60細胞凋謝死亡(Apoptosis)。而且，隨著處理HAs劑量愈高(0, 0.05, 0.1, 0.2, 0.5, 1, 3, 4 mg/ml)以及時間越長(0, 12, 24, 48 h)，HAs所引起HL-60細胞的死亡現象也益發明顯，其中包括細胞型態的改變。再者，以Western blotting方法，亦觀察到細胞內Cytochrome c, tBid, Fas, FasL表現量增加，JNK, p38, c-jun, p53磷酸化及Caspase activity亦上升，故我們更進一步使用p38MAPK訊息傳遞路徑的抑制劑(SB203580)，發現有效的抑制HAs所誘導之Cytochrome c, Fas, FasL, Caspase-3的表現及減少JNK, p38, c-jun, p53之磷酸化，而使細胞走向凋亡的路徑。由此我們推測HAs抑制HL-60細胞生長的作用機轉，可能是透過p38MAPK訊息傳遞路徑，且進一步導致細胞凋亡。由於，目前洛神花在國內容易栽培，產率高，而HAs也容易分離，因此本研究首先探討HAs促進癌細胞凋謝死亡，並探討其分子機制，本研究成果將可應用於發展新藥。
Hibiscus sabdariffa Linne (Malvaceae), an attractive plant believed to be native to Africa, is cultivated in Sudan and in eastern and Taiwan. Cause our laboratory was strive for developing the chemopreventive agents of natural plant, we hope to achieve prevent or delay the tumor progression. Anthocyanins were widespread exist in many vegetables and fruits. Some report demonstrated that anthocyanins extracted from Hibiscus sabdariffa Linne, Hibiscus anthocyanins (HAs), have antioxidant activity and liver protection. Therefore, in this study, we used HAs to explore the effect of HAs on the human cancer cells. The result showed that HAs can caused cancer cells apoptosis, especially HL-60 cells. Using the flow cytometery and DNA fragmentation assay, we found that treatment of HAs (0, 0.05, 0.1, 0.2, 0.5, 1, 3, 4 mg/ml and 0, 12, 24, 48 h) marked induced HL-60 cells apoptosis. The result also showed that increased cytochrome c, tBid, Fas and FasL expression and stimulation of phosphorylation of p53, JNK and p38 in HAs treated HL-60 cells. We further used SB203580 (p38 inhibitor) to block cellular apoptosis and evaluate its effect on the HAs-induced HL-60 death. Data showed SB203580 has strong potential to inhibit HL-60 cell apoptosis and related proteins expression and phosphorylation. Therefore, we suggested that HAs-mediated HL-60 apoptosis via p38-FasL and p53/Bax pathway, According to these results, we expect it could application for developing a new chemopreventive agent. |
