Rhein: A Review of Pharmacological Activities

Rhein (4, 5-dihydroxyanthraquinone-2-carboxylic acid) is a lipophilic anthraquinone extensively found in medicinal herbs, such as Rheum palmatum L., Cassia tora L., Polygonum multiflorum Thunb., and Aloe barbadensis Miller, which have been used medicinally in China for more than 1,000 years. Its biological activities related to human health are being explored actively. Emerging evidence suggests that rhein has many pharmacological effects, including hepatoprotective, nephroprotective, anti-inflammatory, antioxidant, anticancer, and antimicrobial activities. 
Rhein (4,5-dihydroxyanthraquinone-2-carboxylic acid,  is a lipophilic anthraquinone extensively found in medicinal herbs Rheum palmatum L., Cassia tora L., Polygonum multiflorum Thunb. and Aloe barbadensis Miller, and so on, which have been used medicinally in China for more than 1,000 years. Diarrhea, the most common side effect, is well tolerated in humans. Rhein exhibits linear pharmacokinetics between 50 and 200 mg  and has many pharmacological effects, including hepatoprotective, nephroprotective, anti-inflammatory, antioxidant, anticancer, and antimicrobial activities These pharmacological effects lay the foundation for the treatment of hepatic disease , osteoarthritis , diabetes , atherosclerosis , and various cancers, such as nasopharyngeal carcinoma , tongue cancer,hepatocellular carcinoma , and lung cancer.