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Evidence-Based Complementary and Alternative Medicine
Volume 2018 (2018), Article ID 7835128, 7 pages
Research Article

Alleviating the Intestinal Absorption of Rhein in Rhubarb through Herb Compatibility in Tiaowei Chengqi Tang in Caco-2 Cells

School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China

Correspondence should be addressed to Xiaobo Li

Received 17 November 2017; Accepted 28 December 2017; Published 30 January 2018

Academic Editor: Raffaele Capasso

Copyright © 2018 Ying Peng et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Tiaowei Chengqi Tang (TWCQT) is composed of rhubarb, processed liquorice, and Natrii Sulfas, which is used as a purgative in traditional Chinese medicine (TCM). This study focused on the intestinal absorption of rhein in disassembly of the TWCQT extracts through the Caco-2 cell monolayer model to explicate the possible detoxification mechanism of herb-herb compatibility in TWCQT. The results showed that the intestinal absorption of rhein occurred through active diffusion, and rhein might be composed of breast cancer resistance protein (BCRP) substrates. The extract of processed liquorice increased the exclusion rate and reduced intracellular uptake of rhein. The consistent results observed in TWCQT further implied that processed liquorice in TWCQT could suppress the absorption of rhein across the Caco-2 cell monolayer. It has therefore been concluded that the active ingredients of processed liquorice may play a critical role in reducing the intestinal absorption of rhein to alleviate the toxicity of rhubarb in TWCQT. Because of BCRP’s involvement in rhein transport, we conjectured that some components in processed liquorice could inhibit the transport of rhein, possibly by mediating BCRP. These results would provide new insight into this ancient drug combination in toxicity reduction and clinical use.