Toxicological evaluation of, red rice yeast extract, Xuezhikang: Acute, 26-week chronic and genotoxicity studies

Xuezhikang (XZK), an extract derived from red yeast rice, is commonly employed as a traditional Chinese medicine for treating coronary heart disease, improving endothelial function, decreasing blood lipids and preventing other cardiovascular events both within China and globally. However, there have not been studies of the toxicity associated with XZK. In this publication we hope to summarize and evaluate an acute study, a 26-week chronic toxicity study, and the genetic toxicity potential of XZK. Firstly, Sprague Dawley (SD) rats were treated with XZK at dose of 10 g/kg to observe the acute toxicity. Then, we sought to assess the toxicity of XZK (0, 500, 1000, and 2000 mg/kg) in SD rats for 26 weeks with a 4-week recovery period. Lastly, we assessed the genotoxicity of XZK utilizing an Ames test, chromosomal aberration assay, and mammalian micronucleus test. The results of the acute study, XZK did not induce toxicity up to the maximum doses of 10 g/kg in rats, so an LD50 could not be determined. In the chronic study, XZK administrated via gavage did not alter weight, food intake, urinalysis parameters, hematological analysis parameters, organ weight, organ to weight ratio, microscopic and macroscopic examination of organs. Also, we found no genotoxicity markers at any dose of XZK tested. The results revealed that the no observed adverse effect level (NOAEL) for XZK, based on the 26-week toxicity study, was 2000 mg/kg.