[news]槲寄生——癌症的死亡之吻

ranchgirl

槲寄生是圣诞节重要元素之一，同时作为一种药物在结肠癌患者治疗中也发挥重要作用。
在澳大利亚阿德莱德大学，科学家们对槲寄生提取物是否能够作为化疗药的辅助用药，又或者是直接替代化疗药作为结肠癌治疗药物充满兴趣。
在西方国家，结肠癌是癌症造成死亡的第2大原因。在欧洲，槲寄生提取物已经被允许作为结肠癌患者的治疗使用，但在澳大利亚和美国等其它国家，由于科学实验的缺乏仍未被允许使用。
Zahra Lotfollahi是一名来自阿德莱德大学的健康科学学生。在获得荣誉学士学位的课题中，她比较了3种槲寄生提取物和化疗药物对结肠癌细胞的作用。此外，她还比较了槲寄生提取物和化疗药物对正常肠道细胞的作用。
在她的研究中，她发现其中一种槲寄生提取物（生长在白蜡树上一种被叫做Fraxini的槲寄生）对体外培养的结肠癌细胞具有很强杀伤作用，同时相对于化疗药，它对正常肠道细胞的作用则显得温和许多。
值得关注的是，与化疗药物相比Fraxini提取物对结肠癌细胞甚至具有更强的杀伤作用。Lotfollahi 说：“这是一个十分重要的结果，因为我们知道化疗药物不仅杀伤肿瘤细胞同时对正常细胞也具有杀伤作用。这将对患者造成诸多严重的副作用，例如口腔粘膜炎症（口腔溃疡）、脱发”。
“我们的研究表明单独应用Fraxini提取物能够有效降低结肠癌细胞活性。而在一定浓度下，Fraxini同样能够增强化疗药物对肿瘤细胞的杀伤作用”。
Lotfollahi 说：“在实验中所检测的3种提取物以及化疗药物中，只有Fraxini对正常的肠道细胞表现出较低的杀伤作用。这表明Fraxini是一个既能够增加对肿瘤细胞杀伤作用同时又能减少副作用的潜在药物。但是，我们仍然需要更多的实验来验证这个结果”。
Gordon Howarth是阿德莱德大学的教授，一位癌症协会的高级研究人员，同时也是Lotfollahi的主管之一。他说：“槲寄生提取物已经作为重要的替代治疗药物很多年，但是了解其背后的作用机制显得十分重要”。
“尽管生长在白蜡树上的槲寄生是检测的3种提取物中最有效的，但是，在还没检测的生长在其他植物上的槲寄生可能具有更强的作用”。
Howarth教授说：“这只是重要的第1步，我们希望能够引领跟多的研究，最后能够在澳大利亚进行槲寄生提取物的临床试验。

ranchgirl

http://www.medicalnewstoday.com/releases/253468.php
Mistletoe - The Kiss Of Death To Cancer?
Mistletoe has become an important symbol of Christmas but it also has the potential to play a vital role as an alternative therapy for sufferers of colon cancer.

At the University of Adelaide in Australia, scientists are interested in how the extract of mistletoe could either assist chemotherapy or act as an alternative to chemotherapy as a treatment for colon cancer.

Colon cancer is the second greatest cause of cancer death in the Western world. Mistletoe extract is already authorized for use by sufferers of colon cancer in Europe, but not in some countries such as Australia and the United States due to a lack of scientific testing.

For her Honours research project recently completed at the University of Adelaide, Health Sciences student Zahra Lotfollahi compared the effectiveness of three different types of mistletoe extract and chemotherapy on colon cancer cells. She also compared the impact of mistletoe extract and chemotherapy on healthy intestinal cells.

In her laboratory studies, she found that one of the mistletoe extracts - from a species known as Fraxini (which grows on ash trees) - was highly effective against colon cancer cells in cell culture and was gentler on healthy intestinal cells compared with chemotherapy.

Significantly, Fraxini extract was found to be more potent against cancer cells than the chemotherapy drug.

"This is an important result because we know that chemotherapy is effective at killing healthy cells as well as cancer cells. This can result in severe side effects for the patient, such as oral mucositis (ulcers in the mouth) and hair loss," Ms Lotfollahi says.

"Our laboratory studies have shown Fraxini mistletoe extract by itself to be highly effective at reducing the viability of colon cancer cells. At certain concentrations, Fraxini also increased the potency of chemotherapy against the cancer cells.

"Of the three extracts tested, and compared with chemotherapy, Fraxini was the only one that showed a reduced impact on healthy intestinal cells. This might mean that Fraxini is a potential candidate for increased toxicity against cancer, while also reducing potential side effects. However, more laboratory testing is needed to further validate this work," Ms Lotfollahi says.

"Mistletoe extract has been considered a viable alternative therapy overseas for many years, but it's important for us to understand the science behind it," says one of Ms Lotfollahi's supervisors, the University of Adelaide's Professor Gordon Howarth, a Cancer Council Senior Research Fellow.

"Although mistletoe grown on the ash tree was the most effective of the three extracts tested, there is a possibility that mistletoe grown on other, as yet untested, trees or plants could be even more effective.

"This is just the first important step in what we hope will lead to further research, and eventually clinical trials, of mistletoe extract in Australia," Professor Howarth says.