Red Yeast Rice, “Hongqu”, used in Chinese foods, has its food and medicinal value dated back more than a thousand years ago. It consists mainly of nonglutinous rice, red yeast, and byproducts of the fermentation. Production of red yeast rice is via fermentation of the food fungus, Monascus purpureus, on steamed rice. Its medicinal value is recorded by Li Shizhen in his book, Compendium of Materia Medica, which red yeast rice promotes digestion and stimulates blood circulation.
Randomnized, double blind clinical trials are conducted to demonstrate its cholesterol-lowering effects1-3. One placebo-controlled clinical trial using red yeast rice reduces blood cholesterol levels by about 18% in 8 weeks. Its low-density lipoprotein (LDL) reducing effects is likely due to monacolin K and 13 other monacolins produced via the fermentation process. These biological compounds also help to lower production of cholesterol in the liver1. Monacolin K reduces cholesterol via blocking HMG CoA reductaste through competitive inhibition.
It is common nowadays that people consume both western drug prescriptions and nutraceuticals to control chronic medical conditions. However, chemicals from herbs and food interact with medicinal drugs, which results in a change of bioavailability, affecting efficacy of both forms of treatment4. Sometimes, toxicity may also be triggered.
In Eu Yan Sang CholesFREE, there is an additional washing process, in which the polar fraction of red yeast rice (including citrinin) is removed. Citrinin is a mycotoxin, which is found to be nephtotoxic in vitro and animal model experiments.
Coadministration of red yeast rice extracts and drug verapamil in in-vitro and in-vivo assays conducted by Nanyang Polytechnic researchers, the “untreated” red yeast rice resulted in higher verapamil levels in rats. This increased drug bioavailability could be due to inhibition of P-gp and CYPs4. (P-gp and CYPs are drug transporters and conjugation enzymes respectively, that limits cellular uptake from intestinal lumen into epithelial cells, enhancing excretion of drugs out of hepatocytes and breakdown of clinically used drugs.)
Plasma concentrations of verapamil in the SD rats of ‘‘untreated’’ and ‘‘treated’’ RYR treated group and the control treated group (saline).
1. DJ Becker, RY Gordon et al. Red Yeast Rice for Dyslipidemia in statin-intolerant patients. Annals of Internal Medicine 2009, 150: 830-839
2. D Heber, I Yip et al. Cholesterol-lowering effects of a proprietary Chinese red-yeast rice dietary supplement. Am J Clin Nutr 1999, 69: 231-236
3. JY Ma, YG Guo et al. Constituents of Red Yeast Rice, a Traditional Chinese Food and Medicine. J Agri Food Chem 2000, 48: 5220-5225
4. WT Fung, J Lee et al. Assessment of Extracts from Red Yeast Rice for herb-drug interaction by in-vitro and in-vivo assays. Scientific reports 2012, 2:298