Emodin is a naturally-occurring anthraquinone found in a variety of plants used in traditional Chinese medicine. Purified emodin has diverse effects, including the suppression of inflammation, dyslipidemia, and cancer. At a molecular level, emodin directly and selectively inhibits casein kinase II (IC50 = 0.89 μM). Through this action, it inhibits the COP9 signalosome, causing the stabilization of the tumor suppressor p53. Moreover, emodin acts as a phytoestrogen, binding human estrogen receptors and blocking 17β-estradiol binding with Ki values of 0.77 and 1.5 μM for ERα and ERβ, respectively.
