Aloe-Emodin and Emodin

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Emodin and aloe-emodin are aglycone derivatives found in cascara, as well as other plants, which have been shown to have anticancer properties in numerous in vitro and animal studies.7


A systematic review identified 38 in vitro studies, which demonstrated that aloe-emodin inhibits cancer cell proliferation, migration, and invasion and induces cell cycle arrest and apoptosis.8 Mechanisms for these properties include inhibition of mTORC2 and Akt in prostate cancer cells, inhibition of HER2 expression in HER2-positive breast cancer cells, and immunomodulatory effects in melanoma cancer cells.9-11 Aloe-emodin also enhanced the effect of dabrafenib in BRAF-mutant melanoma cancer cells.11

In animal models, dietary aloe-emodin prevented CRC tumor development in an Apc-deficient mouse model and also reduced the number of CRC tumors in a colitis-related colon carcinogenesis model.12 Nude mice bearing orthotopic HER2-positive breast cancer cells demonstrated a decrease in tumor size and weight with aloe-emodin in a dose-dependent manner.10 Tumor tissue from these mice showed downregulation of HER2 overexpression with aloe-emodin treatment.


Emodin has similarly been demonstrated to inhibit cancer cell proliferation, migration, and invasion, reduce cell viability, and induce cell cycle arrest and apoptosis.13-21 Some mechanisms that have been identified include promoting reactive oxygen species production and downregulating CXCR4 and VEGFR2 expression and STAT3 activation.16,22,13

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Many of the in vitro findings have been confirmed in animal models. Emodin inhibited the growth of orthotopic breast cancer tumors and attenuated metastasis and angiogenesis.14,15,23 Emodin also inhibited tumor growth in several studies of hepatocellular carcinoma, and oral and lung cancer.13,16,23,25 Some studies showed that emodin decreased angiogenesis or suppressed metastasis.16,22

Results have, however, been mixed in models of CRC. Though one study showed that emodin suppressed tumor growth in a xenograft model, another study found no significant difference in tumor growth.17,26 A study that treated rats with cascara for 13 weeks found no aberrant colonic crypt foci.27


Cascara use is not recommended because there are insufficient data for establishing its safety, and there have been reports of liver injury with high doses.28 It is, however, unlikely to cause colorectal adenomas or carcinomas. The cascara constituents, aloe-emodin and emodin, have anticancer properties in vitro and in animal models, and may therefore warrant additional studies in humans.


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  17. Ma YS, Weng SW, Lin MW, et al. Antitumor effects of emodin on LS1034 human colon cancer cells in vitro and in vivo: roles of apoptotic cell death and LS1034 tumor xenografts model. Food Chem Toxicol. 2012;50:1271-8. doi: 10.1016/j.fct.2012.01.033
  18. Lee KH, Lee MS, Cha EY, et al. Inhibitory effect of emodin on fatty acid synthase, colon cancer proliferation and apoptosis. Oncol Rep. 2017;15:2163-73. doi: 10.3892/mmr.2017.6254
  19. Guo HC, Bu HQ, Luo J, et al. Emodin potentiates the antitumor effects of gemcitabine in PANC-1 pancreatic cancer xenograft model in vivo via inhibition of inhibitors of apoptosis. Int J Oncol. 2012;40:1849-57. doi: 10.3892/ijo.2012.1389
  20. Li X, Wang H, Wang J, et al. Emodin enhances cisplatin-induced cytotoxicity in human bladder cancer cells through ROS elevation and MRP1 downregulation. BMC Cancer. 2016;16:578-88. doi: 10.1186/s12885-016-2640-3
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