Department of Pharmaceutical Sciences, Howard University, Washington, DC 20059, USA.
Anticancer Agents Med Chem. 2011 Mar;11(3):280-4. doi: 10.2174/187152011795347504.
Previous cancer chemoprevention studies from our laboratories and by other investigators have demonstrated that the extract of red beetroot (Beta vulgaris L.), the FDA approved red food color E162, can be effective in suppressing the development of multi-organ tumors in experimental animals. To further explore this finding, we have compared the cytotoxic effect of the red beetroot extract with anticancer drug, doxorubicin (adriamycin) in the androgen-independent human prostate cancer cells (PC-3) and in the well-established estrogen receptor-positive human breast cancer cells (MCF-7). This red colored anticancer antibiotic was selected for comparative cytotoxic study because its chemical structure with a planar configuration of an aromatic chromophore attached to a sugar molecule is remarkably similar to that of betanin, the beetroot extract constituent primarily responsible for its red color. Both doxorubicin and the beetroot extract exhibited a dose-dependent cytotoxic effect in the two cancer cell lines tested. Although the cytotoxicity of the beetroot extract was significantly lower when compared to doxorubicin, it continued to decrease the growth rate of the PC-3 cells (3.7% in 3 days vs. 12.5% in 7 days) when tested at the concentration of 29 µg/ml. In contrast, doxorubicin, at the same concentration level, completely inhibited the growth of the PC-3 cells in three days. Similarly, comparative studies in the normal human skin FC and liver HC cell lines showed that the beetroot extract had significantly lower cytotoxic effect than doxorubicin (8.6% vs. 100%, respectively, at 29 µg/ml concentration of each, three-day test period). The results suggest that betanin, the major betacyanin constituent, may play an important role in the cytotoxicity exhibited by the red beetroot extract. Further studies are needed to evaluate the chemopreventive potentials of the beetroot extract when used alone or in combination with doxorubicin to mitigate the toxic side-effects of the latter.
先前的癌症化学预防研究表明，我们实验室和其他研究人员的研究表明，红甜菜根（Beta vulgaris L.）提取物，即美国食品药品监督管理局批准的红色食用色素 E162，可以有效抑制实验动物多器官肿瘤的发展。为了进一步探索这一发现，我们比较了红甜菜根提取物与抗癌药物阿霉素（多柔比星）在雄激素非依赖性人前列腺癌细胞（PC-3）和成熟的雌激素受体阳性人乳腺癌细胞（MCF-7）中的细胞毒性作用。这种红色抗癌抗生素被选为比较细胞毒性研究的对象，因为它的化学结构与附着在糖分子上的芳香发色团的平面构型与甜菜根提取物的主要成分甜菜红素非常相似，甜菜红素主要负责其红色。阿霉素和甜菜根提取物在两种测试的癌细胞系中均表现出剂量依赖性的细胞毒性作用。尽管与阿霉素相比，甜菜根提取物的细胞毒性明显较低，但当在 29µg/ml 的浓度下测试时，它仍继续降低 PC-3 细胞的生长速度（3 天内为 3.7%，7 天内为 12.5%）。相比之下，相同浓度水平的阿霉素在三天内完全抑制了 PC-3 细胞的生长。同样，在正常人类皮肤 FC 和肝脏 HC 细胞系中的比较研究表明，甜菜根提取物的细胞毒性明显低于阿霉素（分别为 29µg/ml 浓度下的 8.6%和 100%，为期三天的测试期）。结果表明，甜菜红素，即主要的甜菜红素成分，可能在红甜菜根提取物的细胞毒性中发挥重要作用。需要进一步研究单独使用或与阿霉素联合使用时甜菜根提取物的化学预防潜力，以减轻后者的毒性副作用。
