Emodin

Emodin is one of the main active ingredient of Rheum palmatum, and has anti-inflammatory, anti-bacterial, anti-viral and other effects. In recent years, it arouse concern since it has a significant anti-tumor effect with low toxicity. In this paper we mainly report the anti-cancer effects of emodin according to the studies of the past five years, including four parts such as inhibit tumor growth, inhibit migration and invasion, enhance the efficacy of combination therapy, increase chemosensitivity and attenuated side effects. We hope that our work may provide a reference for further study.

The authors request to change the corresponding author's name as Ali A Alshatwi* from P. Subash-Babu in author list.

Although reactive oxygen species (ROS) work as second messengers at sublethal concentrations, higher levels of ROS can kill cancer cells. Since cellular ROS levels are determined by a balance between ROS generation and removal, the combination of ROS generators and the depletion of reducing substances greatly enhance ROS levels. Emodin (1,3,8-trihydroxy-6-methyl anthraquinone), a natural anthraquinone derivative from the root and rhizome of numerous plants, is a ROS generator that induces apoptosis in cancer cells. The major enzyme to generate mitochondrial NADPH is the mitochondrial isoenzyme of NADP+-dependent isocitrate dehydrogenase (IDH2). In this report, we demonstrate that IDH2 knockdown effectively enhances emodin-induced apoptosis of mouse melanoma B16F10 cells through the regulation of ROS generation. Our findings suggest that suppression of IDH2 activity results in perturbation of the cellular redox balance and, ultimately, exacerbates emodin-induced apoptotic cell death in B16F10 cells.