Allergy Research Group, University Medical Center Freiburg, Freiburg, Germany.
PLoS One. 2013 Apr 17;8(4):e62168. doi: 10.1371/journal.pone.0062168. Print 2013.
Mistletoe extracts are often used in complementary cancer therapy although the efficacy of that therapy is controversially discussed. Approved mistletoe extracts contain mainly water soluble compounds of the mistletoe plant, i.e. mistletoe lectins. However, mistletoe also contains water-insoluble triterpenoids (mainly oleanolic acid) that have anti-tumorigenic effects. To overcome their loss in watery extracts we have solubilized mistletoe triterpenoids with cyclodextrins, thus making them available for in vivo cancer experiments.
B16.F10 subcutaneous melanoma bearing C57BL/6 mice were treated with new mistletoe extracts containing both water soluble compounds and solubilized triterpenoids. Tumor growth and survival was monitored. In addition, histological examinations of the tumor material and tumor surrounding tissue were performed.
Addition of solubilized triterpenoids increased the anti-tumor effects of the mistletoe extracts, resulting in reduced tumor growth and prolonged survival of the mice. Histological examination of the treated tumors showed mainly tumor necrosis and some apoptotic cells with active caspase-3 and TUNEL staining. A significant decrease of CD31-positive tumor blood vessels was observed after treatment with solubilized triterpenoids and different mistletoe extracts.
We conclude that the addition of solubilized mistletoe triterpenoids to conventional mistletoe extracts improves the efficacy of mistletoe treatment and may represent a novel treatment option for malignant melanoma.
槲寄生提取物常被用于癌症的补充治疗，尽管其疗效存在争议。已批准的槲寄生提取物主要含有水溶性化合物，即槲寄生凝集素。然而，槲寄生还含有水不溶性三萜类化合物（主要是齐墩果酸），具有抗肿瘤作用。为避免其在水性提取物中的损失，我们用环糊精对槲寄生三萜类化合物进行了增溶，从而使其可用于体内癌症实验。
用 B16.F10 皮下黑色素瘤荷瘤 C57BL/6 小鼠进行了含有水溶性化合物和增溶三萜类化合物的新型槲寄生提取物的治疗实验。监测肿瘤生长和存活情况。此外，还对肿瘤组织和肿瘤周围组织进行了组织学检查。
增溶三萜类化合物的加入增加了槲寄生提取物的抗肿瘤作用，导致肿瘤生长减少，小鼠存活时间延长。对治疗后的肿瘤进行组织学检查显示，主要为肿瘤坏死和一些凋亡细胞，有活性 caspase-3 和 TUNEL 染色。在用增溶三萜类化合物和不同槲寄生提取物治疗后，观察到 CD31 阳性肿瘤血管明显减少。
我们得出结论，将增溶的槲寄生三萜类化合物加入常规槲寄生提取物中可提高槲寄生治疗的疗效，可能为恶性黑色素瘤提供一种新的治疗选择。
